Maternal & Newborn Atlas
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Antihypertensive drug treatment for non-severe hypertension in pregnancy

Using blood pressure medicines in pregnancy when blood pressure is raised but not yet severe, instead of waiting until it becomes severe. This is a treatment strategy, not one drug. Different sources use different cut-offs and targets, so each target is kept with the claim that reports it.

  • Intervention
  • In this atlas

Overview

Technical summary

Strategy of drug treatment for non-severe hypertension in pregnancy. CHAP treated mild chronic hypertension to a goal below 140/90 mm Hg, compared with treatment only if severe hypertension developed (systolic 160 or diastolic 105 mm Hg or higher); first-line drugs were labetalol or extended-release nifedipine. NICE NG133 1.3.9 gives a target of 135/85 mmHg whenever medicines are used to treat hypertension in pregnancy, and its management tables for gestational hypertension and pre-eclampsia say 135/85 mmHg or less. WHO 2020 recommends offering drug treatment for non-severe hypertension (140 to 159 systolic and/or 90 to 109 diastolic) with no numeric target. WHO also says calcium channel blockers should be avoided, and WHO’s evidence summary lists nifedipine among the calcium channel blockers, while CHAP used extended-release nifedipine as first line; the atlas records this difference and does not reconcile it. The WHO 2020 recommendation predates the CHAP report (2022). Targets belong to each claim’s context.

About this intervention

Type
Medicine
Mechanism
Not reported

Claims and evidence

Context Infants of women enrolled in CHAP, assessed at birth for small-for-gestational-age birth weight, United States

Recipient
Newborn
Population
Infants born to the women in the trial who had birth-weight data: 1146 in the treated group and 1124 in the control group in the complete-case analysis. The infants were exposed through their mothers’ treatment; they were not treated themselves. The women enrolled before 23 weeks, and the gestational age at birth was not restricted by the source.
Care setting
Births at CHAP sites in the United States; the manuscript does not describe the birth setting.
Geography
United States
Life stage
Newborn, birth weight measured at birth
Gestational age
Not reported
Postnatal age
0 days to 0 days
Follow-up
Birth weight at birth. Only the complete-case analysis has a count of infants; the adjusted analysis imputes missing values.
Eligibility: 1 inclusion criterion; 1 exclusion criterion
Included
  • Infants of women enrolled in CHAP before 23 weeks of gestation who have birth-weight data (the manuscript does not say whether stillbirths are included)
Excluded
  • Infants of women without birth-weight data are missing from the complete-case counts

  • Safety Interventional Certainty not assessed

    In CHAP the mothers were treated, and the safety question was the baby’s growth. Babies born small for their gestational age (birth weight below the 10th percentile) numbered 128 of 1146 with data in the treated group (11.2%) and 117 of 1124 in the control group (10.4%). The adjusted risk ratio was 1.04 (95% CI 0.82 to 1.31). The interval includes no difference, so the trial did not show a clear change in this safety outcome.

    Applies to Newborn
    • Infants born to the women in the trial who had birth-weight data: 1146 in the treated group and 1124 in the control group in the complete-case analysis. The infants were exposed through their mothers’ treatment; they were not treated themselves. The women enrolled before 23 weeks, and the gestational age at birth was not restricted by the source.
    • Births at CHAP sites in the United States; the manuscript does not describe the birth setting.
    • United States
    • Newborn, birth weight measured at birth
    • Gestational age Not reported
    • Postnatal age 0 days to 0 days
    Follow-up Birth weight at birth. Only the complete-case analysis has a count of infants; the adjusted analysis imputes missing values.
    Certainty method
    Not assessed
    Limitations
    The trial was powered to detect a relative difference of 35% or more in small-for-gestational-age birth weight, so a smaller increase cannot be ruled out. The percentages come from the 2270 patients with sufficient data (complete-case analysis of the safety outcome); the adjusted risk ratio comes from a multiple-imputation analysis of all 2408 patients (Table 2, N = 2408). Open-label design, one country. The recipient is the newborn, exposed through the mother’s treatment.
    Last checked
    Not recorded
    Next evidence check due
    Not scheduled
    Sources and citations (4)

    1. Supports Treatment for Mild Chronic Hypertension during Pregnancy

      Publication · Massachusetts Medical Society (N Engl J Med 386(19):1781-1792) · Edition Version of record not fetched (HTTP 403, fetch-log label mb-nejm-NEJMoa2201295.html). The abstract and bibliographic data come from PubMed. Full-text facts and tables come from the NIH author manuscript PMC9575330 (NIHMS1827155). Crossref gives the publisher and issue data. · Published 2022-05-12 · doi: 10.1056/NEJMoa2201295

      Locator
      Abstract, RESULTS, sentence 3
      How it applies
      PubMed abstract of the primary report.
      Retrieved
      Source effective date
      Not reported
      Source state
      Current
      Snapshot hash
      0d4e3df2a54e7410e41088da17ab93607e2184d8c086a69f5d47053347f746fe
      Reuse basis
      Bibliographic metadata and short factual extraction only. The PMC author manuscript states that it is available for text mining and may be used consistent with fair use, so it is not committed and quotations stay at 24 words or fewer. The PubMed abstract carries a publisher copyright notice, so only hashes are kept. The version of record is not redistributed.

    2. Supports Treatment for Mild Chronic Hypertension during Pregnancy

      Publication · Massachusetts Medical Society (N Engl J Med 386(19):1781-1792) · Edition Version of record not fetched (HTTP 403, fetch-log label mb-nejm-NEJMoa2201295.html). The abstract and bibliographic data come from PubMed. Full-text facts and tables come from the NIH author manuscript PMC9575330 (NIHMS1827155). Crossref gives the publisher and issue data. · Published 2022-05-12 · doi: 10.1056/NEJMoa2201295

      Locator
      Table 2, row Small for gestational age, <10th percentile
      How it applies
      NIH author manuscript (PMC9575330); available for text mining and fair use only; not checked against the version of record. Counts are complete-case; the first ratio is the multiple-imputation adjusted risk ratio.
      Retrieved
      Source effective date
      Not reported
      Source state
      Current
      Snapshot hash
      ad310682ed3d8aaac7c162897fc3938d64372fc558622433e3c400aecde53559
      Reuse basis
      Bibliographic metadata and short factual extraction only. The PMC author manuscript states that it is available for text mining and may be used consistent with fair use, so it is not committed and quotations stay at 24 words or fewer. The PubMed abstract carries a publisher copyright notice, so only hashes are kept. The version of record is not redistributed.

    3. Background Treatment for Mild Chronic Hypertension during Pregnancy

      Publication · Massachusetts Medical Society (N Engl J Med 386(19):1781-1792) · Edition Version of record not fetched (HTTP 403, fetch-log label mb-nejm-NEJMoa2201295.html). The abstract and bibliographic data come from PubMed. Full-text facts and tables come from the NIH author manuscript PMC9575330 (NIHMS1827155). Crossref gives the publisher and issue data. · Published 2022-05-12 · doi: 10.1056/NEJMoa2201295

      Locator
      Table 2, column headings and footnotes
      How it applies
      Shows which analysis each column comes from.
      Retrieved
      Source effective date
      Not reported
      Source state
      Current
      Snapshot hash
      ad310682ed3d8aaac7c162897fc3938d64372fc558622433e3c400aecde53559
      Reuse basis
      Bibliographic metadata and short factual extraction only. The PMC author manuscript states that it is available for text mining and may be used consistent with fair use, so it is not committed and quotations stay at 24 words or fewer. The PubMed abstract carries a publisher copyright notice, so only hashes are kept. The version of record is not redistributed.

    4. Background Treatment for Mild Chronic Hypertension during Pregnancy

      Publication · Massachusetts Medical Society (N Engl J Med 386(19):1781-1792) · Edition Version of record not fetched (HTTP 403, fetch-log label mb-nejm-NEJMoa2201295.html). The abstract and bibliographic data come from PubMed. Full-text facts and tables come from the NIH author manuscript PMC9575330 (NIHMS1827155). Crossref gives the publisher and issue data. · Published 2022-05-12 · doi: 10.1056/NEJMoa2201295

      Locator
      Methods, Statistical analysis, para 1
      How it applies
      Power of the trial for this outcome.
      Retrieved
      Source effective date
      Not reported
      Source state
      Current
      Snapshot hash
      ad310682ed3d8aaac7c162897fc3938d64372fc558622433e3c400aecde53559
      Reuse basis
      Bibliographic metadata and short factual extraction only. The PMC author manuscript states that it is available for text mining and may be used consistent with fair use, so it is not committed and quotations stay at 24 words or fewer. The PubMed abstract carries a publisher copyright notice, so only hashes are kept. The version of record is not redistributed.

Context Pregnancies of women with mild chronic hypertension and their fetuses and newborns, United States (CHAP primary composite)

Recipient
Mixed recipients
Population
The same women as the maternal CHAP context, with the outcomes of their pregnancies. The primary composite combines a maternal event (pre-eclampsia with severe features up to 2 weeks after birth), pregnancy events (medically indicated preterm birth before 35 weeks and placental abruption) and a fetal or neonatal event (fetal or neonatal death). It is used only for the composite as the trial defined it and is never split by recipient.
Care setting
Recruiting sites of the CHAP Trial Consortium in the United States; see the maternal CHAP context.
Geography
United States
Life stage
Pregnancy and the newborn period
Gestational age
Not reported
Postnatal age
Not reported
Follow-up
Pre-eclampsia counted up to 2 weeks after birth. Fetal or neonatal death is listed at under 28 days in the manuscript table; the registry gives up to 90 days for neonatal death.
Eligibility: 1 inclusion criterion; 1 exclusion criterion
Included
  • The same enrolment criteria as the maternal CHAP context
Excluded
  • The same exclusions as the maternal CHAP context

  • Effect Interventional Certainty not assessed

    In the CHAP trial in the United States, women with mild chronic hypertension who enrolled before 23 weeks of pregnancy and were treated to a blood-pressure goal below 140/90 mm Hg had fewer of the combined serious pregnancy problems than women whose treatment was held back unless their blood pressure became severe. The combined outcome (pre-eclampsia with severe features, a medically indicated preterm birth before 35 weeks, placental abruption, or the death of the fetus or newborn) occurred in 353 of 1170 women with outcome data in the treated group (30.2%) and 427 of 1155 in the control group (37.0%). A separate analysis that fills in missing outcomes gave an adjusted risk ratio of 0.82 (95% CI 0.74 to 0.92).

    Applies to Mixed recipients
    • The same women as the maternal CHAP context, with the outcomes of their pregnancies. The primary composite combines a maternal event (pre-eclampsia with severe features up to 2 weeks after birth), pregnancy events (medically indicated preterm birth before 35 weeks and placental abruption) and a fetal or neonatal event (fetal or neonatal death). It is used only for the composite as the trial defined it and is never split by recipient.
    • Recruiting sites of the CHAP Trial Consortium in the United States; see the maternal CHAP context.
    • United States
    • Pregnancy and the newborn period
    • Gestational age Not reported
    • Postnatal age Not reported
    Follow-up Pre-eclampsia counted up to 2 weeks after birth. Fetal or neonatal death is listed at under 28 days in the manuscript table; the registry gives up to 90 days for neonatal death.
    Certainty method
    Not assessed
    Limitations
    Open-label trial in one country, so women and clinicians knew the assigned strategy. The composite mixes a maternal event with pregnancy events and fetal or neonatal events; the sources do not split it by recipient and the atlas does not either. The percentages and counts come from the complete-case analysis (2325 of 2408 women had enough data); the adjusted risk ratio comes from a multiple-imputation analysis of all 2408. They are different analyses. The authors’ secondary composites of serious maternal complications and of severe neonatal complications did not show clear differences in the abstract; they are about the mother and the newborn separately, so they are not recorded here as claims of their own. Secondary results were not adjusted for multiplicity. For women with newly diagnosed hypertension and for a body-mass index of 40 or more, the risk ratios were close to 1.00 with wide intervals. About 12 women were screened for each woman randomized. The sample size was reduced from a planned 4700 women to a final 2404 that the data and safety monitoring board approved, and the abstract and the Methods word the upper blood-pressure limit differently (below 160/100 vs below 160 and below 105 mm Hg). The registry calls the primary outcome perinatal although it includes a maternal event.
    Last checked
    Not recorded
    Next evidence check due
    Not scheduled
    Sources and citations (6)

    1. Supports Treatment for Mild Chronic Hypertension during Pregnancy

      Publication · Massachusetts Medical Society (N Engl J Med 386(19):1781-1792) · Edition Version of record not fetched (HTTP 403, fetch-log label mb-nejm-NEJMoa2201295.html). The abstract and bibliographic data come from PubMed. Full-text facts and tables come from the NIH author manuscript PMC9575330 (NIHMS1827155). Crossref gives the publisher and issue data. · Published 2022-05-12 · doi: 10.1056/NEJMoa2201295

      Locator
      Abstract, RESULTS, sentence 2
      How it applies
      PubMed abstract of the primary report.
      Retrieved
      Source effective date
      Not reported
      Source state
      Current
      Snapshot hash
      0d4e3df2a54e7410e41088da17ab93607e2184d8c086a69f5d47053347f746fe
      Reuse basis
      Bibliographic metadata and short factual extraction only. The PMC author manuscript states that it is available for text mining and may be used consistent with fair use, so it is not committed and quotations stay at 24 words or fewer. The PubMed abstract carries a publisher copyright notice, so only hashes are kept. The version of record is not redistributed.

    2. Supports Treatment for Mild Chronic Hypertension during Pregnancy

      Publication · Massachusetts Medical Society (N Engl J Med 386(19):1781-1792) · Edition Version of record not fetched (HTTP 403, fetch-log label mb-nejm-NEJMoa2201295.html). The abstract and bibliographic data come from PubMed. Full-text facts and tables come from the NIH author manuscript PMC9575330 (NIHMS1827155). Crossref gives the publisher and issue data. · Published 2022-05-12 · doi: 10.1056/NEJMoa2201295

      Locator
      Table 2, row Primary composite outcome
      How it applies
      NIH author manuscript (PMC9575330); available for text mining and fair use only; not checked against the version of record. Counts are complete-case; the first ratio is the multiple-imputation adjusted risk ratio.
      Retrieved
      Source effective date
      Not reported
      Source state
      Current
      Snapshot hash
      ad310682ed3d8aaac7c162897fc3938d64372fc558622433e3c400aecde53559
      Reuse basis
      Bibliographic metadata and short factual extraction only. The PMC author manuscript states that it is available for text mining and may be used consistent with fair use, so it is not committed and quotations stay at 24 words or fewer. The PubMed abstract carries a publisher copyright notice, so only hashes are kept. The version of record is not redistributed.

    3. Background Treatment for Mild Chronic Hypertension during Pregnancy

      Publication · Massachusetts Medical Society (N Engl J Med 386(19):1781-1792) · Edition Version of record not fetched (HTTP 403, fetch-log label mb-nejm-NEJMoa2201295.html). The abstract and bibliographic data come from PubMed. Full-text facts and tables come from the NIH author manuscript PMC9575330 (NIHMS1827155). Crossref gives the publisher and issue data. · Published 2022-05-12 · doi: 10.1056/NEJMoa2201295

      Locator
      Table 2, column headings and footnotes
      How it applies
      Shows which analysis each column comes from.
      Retrieved
      Source effective date
      Not reported
      Source state
      Current
      Snapshot hash
      ad310682ed3d8aaac7c162897fc3938d64372fc558622433e3c400aecde53559
      Reuse basis
      Bibliographic metadata and short factual extraction only. The PMC author manuscript states that it is available for text mining and may be used consistent with fair use, so it is not committed and quotations stay at 24 words or fewer. The PubMed abstract carries a publisher copyright notice, so only hashes are kept. The version of record is not redistributed.

    4. Background Treatment for Mild Chronic Hypertension during Pregnancy

      Publication · Massachusetts Medical Society (N Engl J Med 386(19):1781-1792) · Edition Version of record not fetched (HTTP 403, fetch-log label mb-nejm-NEJMoa2201295.html). The abstract and bibliographic data come from PubMed. Full-text facts and tables come from the NIH author manuscript PMC9575330 (NIHMS1827155). Crossref gives the publisher and issue data. · Published 2022-05-12 · doi: 10.1056/NEJMoa2201295

      Locator
      Abstract, RESULTS, sentence 4
      How it applies
      Secondary composites without clear differences.
      Retrieved
      Source effective date
      Not reported
      Source state
      Current
      Snapshot hash
      0d4e3df2a54e7410e41088da17ab93607e2184d8c086a69f5d47053347f746fe
      Reuse basis
      Bibliographic metadata and short factual extraction only. The PMC author manuscript states that it is available for text mining and may be used consistent with fair use, so it is not committed and quotations stay at 24 words or fewer. The PubMed abstract carries a publisher copyright notice, so only hashes are kept. The version of record is not redistributed.

    5. Background Treatment for Mild Chronic Hypertension during Pregnancy

      Publication · Massachusetts Medical Society (N Engl J Med 386(19):1781-1792) · Edition Version of record not fetched (HTTP 403, fetch-log label mb-nejm-NEJMoa2201295.html). The abstract and bibliographic data come from PubMed. Full-text facts and tables come from the NIH author manuscript PMC9575330 (NIHMS1827155). Crossref gives the publisher and issue data. · Published 2022-05-12 · doi: 10.1056/NEJMoa2201295

      Locator
      Results, Subgroup analyses
      How it applies
      Subgroups close to no difference; the trial was not powered for subgroups.
      Retrieved
      Source effective date
      Not reported
      Source state
      Current
      Snapshot hash
      ad310682ed3d8aaac7c162897fc3938d64372fc558622433e3c400aecde53559
      Reuse basis
      Bibliographic metadata and short factual extraction only. The PMC author manuscript states that it is available for text mining and may be used consistent with fair use, so it is not committed and quotations stay at 24 words or fewer. The PubMed abstract carries a publisher copyright notice, so only hashes are kept. The version of record is not redistributed.

    6. Background Treatment for Mild Chronic Hypertension during Pregnancy

      Publication · Massachusetts Medical Society (N Engl J Med 386(19):1781-1792) · Edition Version of record not fetched (HTTP 403, fetch-log label mb-nejm-NEJMoa2201295.html). The abstract and bibliographic data come from PubMed. Full-text facts and tables come from the NIH author manuscript PMC9575330 (NIHMS1827155). Crossref gives the publisher and issue data. · Published 2022-05-12 · doi: 10.1056/NEJMoa2201295

      Locator
      Discussion, para 3
      How it applies
      Open-label design and the screening ratio.
      Retrieved
      Source effective date
      Not reported
      Source state
      Current
      Snapshot hash
      ad310682ed3d8aaac7c162897fc3938d64372fc558622433e3c400aecde53559
      Reuse basis
      Bibliographic metadata and short factual extraction only. The PMC author manuscript states that it is available for text mining and may be used consistent with fair use, so it is not committed and quotations stay at 24 words or fewer. The PubMed abstract carries a publisher copyright notice, so only hashes are kept. The version of record is not redistributed.

Context Pregnant women with hypertension who are treated with medicines (NICE NG133 recommendation 1.3.9)

Recipient
Maternal
Population
Pregnant women with hypertension who are being treated with medicines. The recommendation says hypertension in pregnancy and sits in the NICE section on chronic hypertension. NICE’s management tables for gestational hypertension (recommendation 1.4.3, Table 1) and pre-eclampsia (recommendation 1.5.5, Table 2) also give a target of 135/85 mmHg or less once on treatment. The NG133 Context chapter says the update did not review treatment for the three types of hypertension in pregnancy as one group. NICE defines hypertension as 140 mmHg systolic or higher, or 90 mmHg diastolic or higher, and severe hypertension as over 160 mmHg systolic or over 110 mmHg diastolic.
Care setting
Maternity care; the recommendation does not name a setting.
Geography
England. NICE's terms and conditions present the information on its websites as support for people in England who make decisions about funding care (clause 6) and say it is not written as a basis for decisions outside the United Kingdom (clause 8). The guideline page states no jurisdiction of its own.
Life stage
Pregnancy
Gestational age
Not reported
Postnatal age
Not reported
Follow-up
Not applicable (recommendation context)
Eligibility: 1 inclusion criterion; 1 exclusion criterion
Included
  • Pregnant women with hypertension who are using medicines to treat it
Excluded
  • Not stated in the recommendation

  • Recommendation Guidance Certainty not assessed

    NICE advises that when medicines are used to treat hypertension in pregnancy, the aim is a target blood pressure of 135/85 mmHg. NICE marks this recommendation as one it reviewed in 2019. NICE’s management tables for gestational hypertension and for pre-eclampsia give the same target, 135/85 mmHg or less.

    Applies to Maternal
    • Pregnant women with hypertension who are being treated with medicines. The recommendation says hypertension in pregnancy and sits in the NICE section on chronic hypertension. NICE’s management tables for gestational hypertension (recommendation 1.4.3, Table 1) and pre-eclampsia (recommendation 1.5.5, Table 2) also give a target of 135/85 mmHg or less once on treatment. The NG133 Context chapter says the update did not review treatment for the three types of hypertension in pregnancy as one group. NICE defines hypertension as 140 mmHg systolic or higher, or 90 mmHg diastolic or higher, and severe hypertension as over 160 mmHg systolic or over 110 mmHg diastolic.
    • Maternity care; the recommendation does not name a setting.
    • England. NICE's terms and conditions present the information on its websites as support for people in England who make decisions about funding care (clause 6) and say it is not written as a basis for decisions outside the United Kingdom (clause 8). The guideline page states no jurisdiction of its own.
    • Pregnancy
    • Gestational age Not reported
    • Postnatal age Not reported
    Follow-up Not applicable (recommendation context)
    Certainty method
    Not assessed
    Limitations
    NICE’s target of 135/85 mmHg differs from the goal used in the CHAP trial (below 140/90 mm Hg); the atlas records both and does not reconcile them. This record has not checked whether NICE considered CHAP. The update information lists the April 2023 changes to recommendations 1.3.12 and 1.4.4 only for PlGF-based testing, and does not list 1.3.9. The recommendation sits in the chronic hypertension section while its wording is general; the tables for gestational hypertension and pre-eclampsia carry the same target with the words 135/85 mmHg or less, which 1.3.9 does not use. NICE says its update did not review treatment for the three types of hypertension in pregnancy as one group. NICE gives this recommendation no strength label. The page does not state a jurisdiction; England is inferred from the issuer.
    Last checked
    Not recorded
    Next evidence check due
    Not scheduled
    Sources and citations (6)

    1. Supports Hypertension in pregnancy: diagnosis and management (NICE guideline NG133), Recommendations chapter

      Guideline · National Institute for Health and Care Excellence (NICE) · Edition The version shown on 2026-10-11, with a page header that gives 17 April 2023 as the last update. The same bytes came back on a second fetch minutes later. · Published 2019-06-25 · nice: NG133

      Locator
      Recommendation 1.3.9
      How it applies
      NICE guideline NG133; cited and linked only, with no NICE wording on public pages.
      Retrieved
      Source effective date
      2023-04-17
      Source state
      Current
      Snapshot hash
      0cd8548f5807f03a82b3101dc56ebadf674106da9d0aa7e57955d4a823556fca
      Reuse basis
      The page bytes are not committed. Public text is cite_only (Ben's decision of 2026-10-13 (medical-atlas-core issue 2)): public pages state the facts in the atlas's own words, with a citation and a link, and use no NICE wording. NICE reuse terms, read on 2026-10-11: the NICE UK Open Content Licence covers use in a UK setting only, international use outside personal research and study needs a licence and a fee, and the NICE terms and conditions make content available for artificial intelligence purposes only through an approval process, a licence and a fee for international use. This pipeline uses AI agents to read the page, so Ben decided on 2026-10-13 that public pages cite and link NICE and use none of its wording.

    2. Background Hypertension in pregnancy: diagnosis and management (NICE guideline NG133), Recommendations chapter

      Guideline · National Institute for Health and Care Excellence (NICE) · Edition The version shown on 2026-10-11, with a page header that gives 17 April 2023 as the last update. The same bytes came back on a second fetch minutes later. · Published 2019-06-25 · nice: NG133

      Locator
      Section 1.3, subheading above recommendations 1.3.6 to 1.3.12
      How it applies
      Where the recommendation sits.
      Retrieved
      Source effective date
      2023-04-17
      Source state
      Current
      Snapshot hash
      0cd8548f5807f03a82b3101dc56ebadf674106da9d0aa7e57955d4a823556fca
      Reuse basis
      The page bytes are not committed. Public text is cite_only (Ben's decision of 2026-10-13 (medical-atlas-core issue 2)): public pages state the facts in the atlas's own words, with a citation and a link, and use no NICE wording. NICE reuse terms, read on 2026-10-11: the NICE UK Open Content Licence covers use in a UK setting only, international use outside personal research and study needs a licence and a fee, and the NICE terms and conditions make content available for artificial intelligence purposes only through an approval process, a licence and a fee for international use. This pipeline uses AI agents to read the page, so Ben decided on 2026-10-13 that public pages cite and link NICE and use none of its wording.

    3. Supports Hypertension in pregnancy: diagnosis and management (NICE guideline NG133), Recommendations chapter

      Guideline · National Institute for Health and Care Excellence (NICE) · Edition The version shown on 2026-10-11, with a page header that gives 17 April 2023 as the last update. The same bytes came back on a second fetch minutes later. · Published 2019-06-25 · nice: NG133

      Locator
      Table 1 (gestational hypertension, recommendation 1.4.3) and Table 2 (pre-eclampsia, recommendation 1.5.5), row Target blood pressure
      How it applies
      NICE guideline NG133; cited and linked only, with no NICE wording on public pages. The same target appears in both tables.
      Retrieved
      Source effective date
      2023-04-17
      Source state
      Current
      Snapshot hash
      0cd8548f5807f03a82b3101dc56ebadf674106da9d0aa7e57955d4a823556fca
      Reuse basis
      The page bytes are not committed. Public text is cite_only (Ben's decision of 2026-10-13 (medical-atlas-core issue 2)): public pages state the facts in the atlas's own words, with a citation and a link, and use no NICE wording. NICE reuse terms, read on 2026-10-11: the NICE UK Open Content Licence covers use in a UK setting only, international use outside personal research and study needs a licence and a fee, and the NICE terms and conditions make content available for artificial intelligence purposes only through an approval process, a licence and a fee for international use. This pipeline uses AI agents to read the page, so Ben decided on 2026-10-13 that public pages cite and link NICE and use none of its wording.

    4. Background Hypertension in pregnancy: diagnosis and management (NICE guideline NG133), Context chapter

      Guideline · National Institute for Health and Care Excellence (NICE) · Edition Another chapter of NICE guideline NG133, which has no identifier of its own because the Recommendations chapter source already holds the identifier NG133. The version shown on 2026-10-11. NICE lists the guideline as last updated 17 April 2023 and also lists minor changes in October 2023 (see the Update information chapter). · Published 2019-06-25

      Locator
      Context, para 3, scope exclusion
      How it applies
      Scope of the NG133 update.
      Retrieved
      Source effective date
      Not reported
      Source state
      Current
      Snapshot hash
      b664aadc0a8aab948b2a376dee01b23b8c068f5c7c7e3a849c3140fce4a3dd72
      Reuse basis
      The page bytes are not committed. Public text is cite_only (Ben's decision of 2026-10-13 (medical-atlas-core issue 2)): public pages state the facts in the atlas's own words, with a citation and a link, and use no NICE wording. NICE reuse terms, read on 2026-10-11 and recorded in research/setup/notes.md: the NICE UK Open Content Licence covers use in a UK setting only, international use outside personal research and study needs a licence and a fee, and the NICE terms and conditions make content available for artificial intelligence purposes only through an approval process, a licence and a fee for international use. This pipeline uses AI agents to read the page, so Ben decided on 2026-10-13 that public pages cite and link NICE and use none of its wording.

    5. Background Hypertension in pregnancy: diagnosis and management (NICE guideline NG133), Update information chapter

      Guideline · National Institute for Health and Care Excellence (NICE) · Edition The Update information chapter of NICE guideline NG133, as shown on 2026-10-11 with the page header Last updated: 17 April 2023. It lists what changed in June 2019, the minor changes after publication (August 2022, April 2023 and October 2023) and the guideline ISBN. The chapter has no identifier of its own because the Recommendations chapter source already holds the identifier NG133. Cluster B and cluster C fetched this page separately on 2026-10-11 and both returned the same bytes (sha256 248348547ec88c3384b6fb76489a433766acf40e47b5f77d8060516561836a58). The integration step kept this one source and snapshot and redirected the cluster C citations to them. · Published 2019-06-25

      Locator
      Update information, April 2023
      How it applies
      The last listed change to recommendations; 1.3.9 is not named.
      Retrieved
      Source effective date
      2023-04-17
      Source state
      Current
      Snapshot hash
      248348547ec88c3384b6fb76489a433766acf40e47b5f77d8060516561836a58
      Reuse basis
      The page bytes are not committed. Public text is cite_only (Ben's decision of 2026-10-13 (medical-atlas-core issue 2)): public pages state the facts in the atlas's own words, with a citation and a link, and use no NICE wording. NICE reuse terms, read on 2026-10-11 and recorded in research/setup/notes.md: the NICE UK Open Content Licence covers use in a UK setting only, international use outside personal research and study needs a licence and a fee, and the NICE terms and conditions make content available for artificial intelligence purposes only through an approval process, a licence and a fee for international use. This pipeline uses AI agents to read the page, so Ben decided on 2026-10-13 that public pages cite and link NICE and use none of its wording.

    6. Background Hypertension in pregnancy: diagnosis and management (NICE guideline NG133), Update information chapter

      Guideline · National Institute for Health and Care Excellence (NICE) · Edition The Update information chapter of NICE guideline NG133, as shown on 2026-10-11 with the page header Last updated: 17 April 2023. It lists what changed in June 2019, the minor changes after publication (August 2022, April 2023 and October 2023) and the guideline ISBN. The chapter has no identifier of its own because the Recommendations chapter source already holds the identifier NG133. Cluster B and cluster C fetched this page separately on 2026-10-11 and both returned the same bytes (sha256 248348547ec88c3384b6fb76489a433766acf40e47b5f77d8060516561836a58). The integration step kept this one source and snapshot and redirected the cluster C citations to them. · Published 2019-06-25

      Locator
      Update information, June 2019
      How it applies
      The 2019 review that the [2019] marking refers to.
      Retrieved
      Source effective date
      2023-04-17
      Source state
      Current
      Snapshot hash
      248348547ec88c3384b6fb76489a433766acf40e47b5f77d8060516561836a58
      Reuse basis
      The page bytes are not committed. Public text is cite_only (Ben's decision of 2026-10-13 (medical-atlas-core issue 2)): public pages state the facts in the atlas's own words, with a citation and a link, and use no NICE wording. NICE reuse terms, read on 2026-10-11 and recorded in research/setup/notes.md: the NICE UK Open Content Licence covers use in a UK setting only, international use outside personal research and study needs a licence and a fee, and the NICE terms and conditions make content available for artificial intelligence purposes only through an approval process, a licence and a fee for international use. This pipeline uses AI agents to read the page, so Ben decided on 2026-10-13 that public pages cite and link NICE and use none of its wording.

Context Pregnant women with mild chronic hypertension and a singleton pregnancy before 23 weeks, United States (CHAP trial)

Recipient
Maternal
Population
Pregnant women with known or new chronic hypertension and a viable singleton fetus before 23 weeks of gestation. Mild means below the severe thresholds, but the sources word the limit differently. The abstract says blood pressure below 160/100 mm Hg. The Methods required, at randomization, a systolic pressure of 140 to 159 or a diastolic pressure of 90 to 104 mm Hg for patients who “had not received an antihypertensive drug within 24 hours before measurement”, and below 160 and below 105 mm Hg for patients who “had been receiving antihypertensive therapy”. Women with lower pressures were also eligible. The registry gives a minimum age of 12 years and adds that the minimum age varies by center; the manuscript states no age limit.
Care setting
Recruiting sites of the CHAP Trial Consortium in the United States. The Methods say more than 70 recruiting sites; the Results say 2419 women were randomized at 61 sites. The manuscript does not say whether the sites were clinics or hospitals.
Geography
United States
Life stage
Pregnancy, enrolled before 23 weeks of gestation and followed until 6 weeks after birth
Gestational age
up to 22 weeks 6 days (160 days)
Postnatal age
Not reported
Follow-up
Followed until 6 weeks after birth. Pre-eclampsia in the primary composite counted up to 2 weeks after birth.
Eligibility: 3 inclusion criteria; 6 exclusion criteria
Included
  • Known chronic hypertension confirmed by a documented blood-pressure elevation and previous or current antihypertensive therapy, including lifestyle measures; or new chronic hypertension (systolic 140 mm Hg or higher or diastolic 90 mm Hg or higher on at least two occasions at least 4 hours apart before 20 weeks)
  • A viable singleton fetus before 23 weeks of gestation
  • Blood pressure below the severe-hypertension thresholds at randomization, as described in the population text
Excluded
  • Severe hypertension, or a blood pressure that needed more than one medication
  • Known secondary hypertension
  • Multiple fetuses
  • Other serious illnesses or complications, named in advance, that might call for treatment at a lower blood pressure
  • Obstetric conditions that increase fetal risk
  • Contraindications to the first-line drugs recommended for use in pregnant women

  • Effect Interventional Certainty not assessed

    In the CHAP trial, any pre-eclampsia (with or without severe features) occurred in 295 of 1208 women in the treated group (24.4%) and 373 of 1200 women in the control group (31.1%), a risk ratio of 0.79 (95% CI 0.69 to 0.89).

    Applies to Maternal
    • Pregnant women with known or new chronic hypertension and a viable singleton fetus before 23 weeks of gestation. Mild means below the severe thresholds, but the sources word the limit differently. The abstract says blood pressure below 160/100 mm Hg. The Methods required, at randomization, a systolic pressure of 140 to 159 or a diastolic pressure of 90 to 104 mm Hg for patients who “had not received an antihypertensive drug within 24 hours before measurement”, and below 160 and below 105 mm Hg for patients who “had been receiving antihypertensive therapy”. Women with lower pressures were also eligible. The registry gives a minimum age of 12 years and adds that the minimum age varies by center; the manuscript states no age limit.
    • Recruiting sites of the CHAP Trial Consortium in the United States. The Methods say more than 70 recruiting sites; the Results say 2419 women were randomized at 61 sites. The manuscript does not say whether the sites were clinics or hospitals.
    • United States
    • Pregnancy, enrolled before 23 weeks of gestation and followed until 6 weeks after birth
    • Gestational age up to 22 weeks 6 days
    • Postnatal age Not reported
    Follow-up Followed until 6 weeks after birth. Pre-eclampsia in the primary composite counted up to 2 weeks after birth.
    Certainty method
    Not assessed
    Limitations
    This is a secondary outcome, reported without adjustment for multiplicity, so the authors say it should not be used to infer definitive effects. The risk ratio is not described as adjusted in the abstract or the table. The time window for this outcome is not stated in the manuscript text (follow-up ran to 6 weeks after birth; the primary composite counted pre-eclampsia up to 2 weeks after birth). It overlaps with the severe-features part of the primary composite, so the two must not be added. Open-label design, one country.
    Last checked
    Not recorded
    Next evidence check due
    Not scheduled
    Sources and citations (4)

    1. Supports Treatment for Mild Chronic Hypertension during Pregnancy

      Publication · Massachusetts Medical Society (N Engl J Med 386(19):1781-1792) · Edition Version of record not fetched (HTTP 403, fetch-log label mb-nejm-NEJMoa2201295.html). The abstract and bibliographic data come from PubMed. Full-text facts and tables come from the NIH author manuscript PMC9575330 (NIHMS1827155). Crossref gives the publisher and issue data. · Published 2022-05-12 · doi: 10.1056/NEJMoa2201295

      Locator
      Abstract, RESULTS, sentence 5
      How it applies
      PubMed abstract of the primary report.
      Retrieved
      Source effective date
      Not reported
      Source state
      Current
      Snapshot hash
      0d4e3df2a54e7410e41088da17ab93607e2184d8c086a69f5d47053347f746fe
      Reuse basis
      Bibliographic metadata and short factual extraction only. The PMC author manuscript states that it is available for text mining and may be used consistent with fair use, so it is not committed and quotations stay at 24 words or fewer. The PubMed abstract carries a publisher copyright notice, so only hashes are kept. The version of record is not redistributed.

    2. Supports Treatment for Mild Chronic Hypertension during Pregnancy

      Publication · Massachusetts Medical Society (N Engl J Med 386(19):1781-1792) · Edition Version of record not fetched (HTTP 403, fetch-log label mb-nejm-NEJMoa2201295.html). The abstract and bibliographic data come from PubMed. Full-text facts and tables come from the NIH author manuscript PMC9575330 (NIHMS1827155). Crossref gives the publisher and issue data. · Published 2022-05-12 · doi: 10.1056/NEJMoa2201295

      Locator
      Table 3, row Any preeclampsia
      How it applies
      NIH author manuscript (PMC9575330); available for text mining and fair use only; not checked against the version of record.
      Retrieved
      Source effective date
      Not reported
      Source state
      Current
      Snapshot hash
      ad310682ed3d8aaac7c162897fc3938d64372fc558622433e3c400aecde53559
      Reuse basis
      Bibliographic metadata and short factual extraction only. The PMC author manuscript states that it is available for text mining and may be used consistent with fair use, so it is not committed and quotations stay at 24 words or fewer. The PubMed abstract carries a publisher copyright notice, so only hashes are kept. The version of record is not redistributed.

    3. Background Treatment for Mild Chronic Hypertension during Pregnancy

      Publication · Massachusetts Medical Society (N Engl J Med 386(19):1781-1792) · Edition Version of record not fetched (HTTP 403, fetch-log label mb-nejm-NEJMoa2201295.html). The abstract and bibliographic data come from PubMed. Full-text facts and tables come from the NIH author manuscript PMC9575330 (NIHMS1827155). Crossref gives the publisher and issue data. · Published 2022-05-12 · doi: 10.1056/NEJMoa2201295

      Locator
      Table 3, column headings and footnote
      How it applies
      Group sizes and the type of treatment effect.
      Retrieved
      Source effective date
      Not reported
      Source state
      Current
      Snapshot hash
      ad310682ed3d8aaac7c162897fc3938d64372fc558622433e3c400aecde53559
      Reuse basis
      Bibliographic metadata and short factual extraction only. The PMC author manuscript states that it is available for text mining and may be used consistent with fair use, so it is not committed and quotations stay at 24 words or fewer. The PubMed abstract carries a publisher copyright notice, so only hashes are kept. The version of record is not redistributed.

    4. Background Treatment for Mild Chronic Hypertension during Pregnancy

      Publication · Massachusetts Medical Society (N Engl J Med 386(19):1781-1792) · Edition Version of record not fetched (HTTP 403, fetch-log label mb-nejm-NEJMoa2201295.html). The abstract and bibliographic data come from PubMed. Full-text facts and tables come from the NIH author manuscript PMC9575330 (NIHMS1827155). Crossref gives the publisher and issue data. · Published 2022-05-12 · doi: 10.1056/NEJMoa2201295

      Locator
      Methods, Statistical analysis, para 4
      How it applies
      Secondary outcomes are not adjusted for multiplicity.
      Retrieved
      Source effective date
      Not reported
      Source state
      Current
      Snapshot hash
      ad310682ed3d8aaac7c162897fc3938d64372fc558622433e3c400aecde53559
      Reuse basis
      Bibliographic metadata and short factual extraction only. The PMC author manuscript states that it is available for text mining and may be used consistent with fair use, so it is not committed and quotations stay at 24 words or fewer. The PubMed abstract carries a publisher copyright notice, so only hashes are kept. The version of record is not redistributed.

Context Pregnant women with non-severe hypertension (WHO 2020 recommendation 1)

Recipient
Maternal
Population
Pregnant women with non-severe hypertension. WHO uses non-severe and mild to moderate interchangeably and defines them as a diastolic pressure of 90 to 109 mmHg and/or a systolic pressure of 140 to 159 mmHg. The recommendation applies in the context of good quality antenatal care follow-up with regular outpatient monitoring and review.
Care setting
Antenatal care with regular outpatient monitoring and review by an antenatal care provider.
Geography
Global; WHO states the audience as covering all settings.
Life stage
Pregnancy
Gestational age
Not reported
Postnatal age
Not reported
Follow-up
Not applicable (recommendation context)
Eligibility: 1 inclusion criterion; 1 exclusion criterion
Included
  • Women with non-severe hypertension during pregnancy, receiving good quality antenatal care follow-up
Excluded
  • Severe hypertension is outside this recommendation; WHO issues separate guidance on drug treatment for severe hypertension

  • Recommendation Guidance Certainty not assessed

    WHO recommends offering antihypertensive drug treatment to women with non-severe hypertension during pregnancy, as part of good quality antenatal care follow-up. WHO labels it a context-specific recommendation. WHO’s recommendation table gives no numeric blood-pressure target.

    Applies to Maternal
    • Pregnant women with non-severe hypertension. WHO uses non-severe and mild to moderate interchangeably and defines them as a diastolic pressure of 90 to 109 mmHg and/or a systolic pressure of 140 to 159 mmHg. The recommendation applies in the context of good quality antenatal care follow-up with regular outpatient monitoring and review.
    • Antenatal care with regular outpatient monitoring and review by an antenatal care provider.
    • Global; WHO states the audience as covering all settings.
    • Pregnancy
    • Gestational age Not reported
    • Postnatal age Not reported
    Follow-up Not applicable (recommendation context)
    Certainty method
    Not assessed
    Limitations
    Published in 2020, before the CHAP report (2022), so it did not consider CHAP. WHO’s justification says drug treatment probably reduces severe hypertension but may make little or no difference to proteinuria or pre-eclampsia; this is not a GRADE rating of the recommendation, so certainty is not assessed here. WHO also says available evidence suggests calcium channel blockers should be avoided, and its evidence summary lists nifedipine among the calcium channel blockers used in the included trials, while CHAP used extended-release nifedipine as a first-line drug; the atlas records the difference and does not reconcile it. The treatment applies only with regular outpatient monitoring and review.
    Last checked
    Not recorded
    Next evidence check due
    Not scheduled
    Sources and citations (5)

    1. Supports WHO recommendations on drug treatment for non-severe hypertension in pregnancy

      Guideline · World Health Organization · Edition 2020. The WHO publication page shows 11 August 2020; the IRIS record (handle 10665/333816) gives an issue date of 2020-08-13. The text comes from the PDF on IRIS, fetched through the IRIS REST API because the older IRIS bitstream links no longer serve the PDF. Electronic ISBN 978-92-4-000879-3. The guideline predates the CHAP report (2022). Whether WHO has issued a newer recommendation was not checked here. · Published 2020-08-11 · isbn: 978-92-4-000879-3

      Locator
      Table 1, PDF p. 10 (repeated on p. 21), Recommendation 1 with its label
      How it applies
      WHO 2020 guideline, CC BY-NC-SA 3.0 IGO; short quotation with attribution.
      Retrieved
      Source effective date
      Not reported
      Source state
      Current
      Snapshot hash
      d21df49f3ed9eb5ad34f211d0f7921332c514c652923730bd92167610d9d7358
      Reuse basis
      Licensed CC BY-NC-SA 3.0 IGO, as stated in the PDF. Only short quotations with attribution are used, and the PDF is not committed. The non-commercial and share-alike terms need a licensing decision before any text is adapted.

    2. Background WHO recommendations on drug treatment for non-severe hypertension in pregnancy

      Guideline · World Health Organization · Edition 2020. The WHO publication page shows 11 August 2020; the IRIS record (handle 10665/333816) gives an issue date of 2020-08-13. The text comes from the PDF on IRIS, fetched through the IRIS REST API because the older IRIS bitstream links no longer serve the PDF. Electronic ISBN 978-92-4-000879-3. The guideline predates the CHAP report (2022). Whether WHO has issued a newer recommendation was not checked here. · Published 2020-08-11 · isbn: 978-92-4-000879-3

      Locator
      Table 1, PDF p. 10, Justification, bullet 1
      How it applies
      WHO 2020 guideline, CC BY-NC-SA 3.0 IGO; short quotation with attribution.
      Retrieved
      Source effective date
      Not reported
      Source state
      Current
      Snapshot hash
      d21df49f3ed9eb5ad34f211d0f7921332c514c652923730bd92167610d9d7358
      Reuse basis
      Licensed CC BY-NC-SA 3.0 IGO, as stated in the PDF. Only short quotations with attribution are used, and the PDF is not committed. The non-commercial and share-alike terms need a licensing decision before any text is adapted.

    3. Background WHO recommendations on drug treatment for non-severe hypertension in pregnancy

      Guideline · World Health Organization · Edition 2020. The WHO publication page shows 11 August 2020; the IRIS record (handle 10665/333816) gives an issue date of 2020-08-13. The text comes from the PDF on IRIS, fetched through the IRIS REST API because the older IRIS bitstream links no longer serve the PDF. Electronic ISBN 978-92-4-000879-3. The guideline predates the CHAP report (2022). Whether WHO has issued a newer recommendation was not checked here. · Published 2020-08-11 · isbn: 978-92-4-000879-3

      Locator
      Table 1, PDF p. 10, Remarks, bullet 1
      How it applies
      WHO 2020 guideline, CC BY-NC-SA 3.0 IGO; short quotation with attribution.
      Retrieved
      Source effective date
      Not reported
      Source state
      Current
      Snapshot hash
      d21df49f3ed9eb5ad34f211d0f7921332c514c652923730bd92167610d9d7358
      Reuse basis
      Licensed CC BY-NC-SA 3.0 IGO, as stated in the PDF. Only short quotations with attribution are used, and the PDF is not committed. The non-commercial and share-alike terms need a licensing decision before any text is adapted.

    4. Background WHO recommendations on drug treatment for non-severe hypertension in pregnancy

      Guideline · World Health Organization · Edition 2020. The WHO publication page shows 11 August 2020; the IRIS record (handle 10665/333816) gives an issue date of 2020-08-13. The text comes from the PDF on IRIS, fetched through the IRIS REST API because the older IRIS bitstream links no longer serve the PDF. Electronic ISBN 978-92-4-000879-3. The guideline predates the CHAP report (2022). Whether WHO has issued a newer recommendation was not checked here. · Published 2020-08-11 · isbn: 978-92-4-000879-3

      Locator
      Table 1, PDF p. 11, Remarks, bullet 2
      How it applies
      WHO 2020 guideline, CC BY-NC-SA 3.0 IGO; short quotation with attribution.
      Retrieved
      Source effective date
      Not reported
      Source state
      Current
      Snapshot hash
      d21df49f3ed9eb5ad34f211d0f7921332c514c652923730bd92167610d9d7358
      Reuse basis
      Licensed CC BY-NC-SA 3.0 IGO, as stated in the PDF. Only short quotations with attribution are used, and the PDF is not committed. The non-commercial and share-alike terms need a licensing decision before any text is adapted.

    5. Background WHO recommendations on drug treatment for non-severe hypertension in pregnancy

      Guideline · World Health Organization · Edition 2020. The WHO publication page shows 11 August 2020; the IRIS record (handle 10665/333816) gives an issue date of 2020-08-13. The text comes from the PDF on IRIS, fetched through the IRIS REST API because the older IRIS bitstream links no longer serve the PDF. Electronic ISBN 978-92-4-000879-3. The guideline predates the CHAP report (2022). Whether WHO has issued a newer recommendation was not checked here. · Published 2020-08-11 · isbn: 978-92-4-000879-3

      Locator
      Evidence summary, drug list, PDF p. 34 (printed p. 26), under Calcium channel blockers
      How it applies
      WHO 2020 guideline, CC BY-NC-SA 3.0 IGO; short quotation with attribution.
      Retrieved
      Source effective date
      Not reported
      Source state
      Current
      Snapshot hash
      d21df49f3ed9eb5ad34f211d0f7921332c514c652923730bd92167610d9d7358
      Reuse basis
      Licensed CC BY-NC-SA 3.0 IGO, as stated in the PDF. Only short quotations with attribution are used, and the PDF is not committed. The non-commercial and share-alike terms need a licensing decision before any text is adapted.

Guidance

Recommended: Antihypertensive drug treatment for non-severe hypertension in pregnancy

Applies to Maternal
  • Pregnant women with hypertension who are being treated with medicines. The recommendation says hypertension in pregnancy and sits in the NICE section on chronic hypertension. NICE’s management tables for gestational hypertension (recommendation 1.4.3, Table 1) and pre-eclampsia (recommendation 1.5.5, Table 2) also give a target of 135/85 mmHg or less once on treatment. The NG133 Context chapter says the update did not review treatment for the three types of hypertension in pregnancy as one group. NICE defines hypertension as 140 mmHg systolic or higher, or 90 mmHg diastolic or higher, and severe hypertension as over 160 mmHg systolic or over 110 mmHg diastolic.
  • Maternity care; the recommendation does not name a setting.
  • England. NICE's terms and conditions present the information on its websites as support for people in England who make decisions about funding care (clause 6) and say it is not written as a basis for decisions outside the United Kingdom (clause 8). The guideline page states no jurisdiction of its own.
  • Pregnancy
  • Gestational age Not reported
  • Postnatal age Not reported
Follow-up Not applicable (recommendation context)
Issued by
National Institute for Health and Care Excellence (NICE)
Guideline
Hypertension in pregnancy: diagnosis and management (NICE guideline NG133), Recommendations chapter, edition The version shown on 2026-10-11, with a page header that gives 17 April 2023 as the last update. The same bytes came back on a second fetch minutes later.
Strength
No labelled strength (imperative wording: aim for a target) (NICE shows strength through its choice of words, as its guidance on making decisions explains; this recommendation carries no separate strength label and no certainty rating.)
Effective
2019-06-25 (The recommendation is marked [2019]; 25 June 2019 is the guideline publication date. The page was last updated on 17 April 2023, and the update information does not list 1.3.9 as changed.)
Jurisdiction
England. NICE's terms and conditions present the information on its websites as support for people in England who make decisions about funding care (clause 6) and say it is not written as a basis for decisions outside the United Kingdom (clause 8). The guideline page states no jurisdiction of its own.
Supersession
Not checked
Basis
NICE advises that when medicines are used to treat hypertension in pregnancy, the aim is a target blood pressure of 135/85 mmHg. NICE marks this recommendation as one it reviewed in 2019. NICE’s management tables for gestational hypertension and for pre-eclampsia give the same target, 135/85 mmHg or less.

Limitations. NICE’s target of 135/85 mmHg differs from the goal used in the CHAP trial (below 140/90 mm Hg); the atlas records both and does not reconcile them. This record has not checked whether NICE considered CHAP. The update information lists the April 2023 changes to recommendations 1.3.12 and 1.4.4 only for PlGF-based testing, and does not list 1.3.9. The recommendation sits in the chronic hypertension section while its wording is general; the tables for gestational hypertension and pre-eclampsia carry the same target with the words 135/85 mmHg or less, which 1.3.9 does not use. NICE says its update did not review treatment for the three types of hypertension in pregnancy as one group. NICE gives this recommendation no strength label. The page does not state a jurisdiction; England is inferred from the issuer.

Recommended: Antihypertensive drug treatment for non-severe hypertension in pregnancy

Applies to Maternal
  • Pregnant women with non-severe hypertension. WHO uses non-severe and mild to moderate interchangeably and defines them as a diastolic pressure of 90 to 109 mmHg and/or a systolic pressure of 140 to 159 mmHg. The recommendation applies in the context of good quality antenatal care follow-up with regular outpatient monitoring and review.
  • Antenatal care with regular outpatient monitoring and review by an antenatal care provider.
  • Global; WHO states the audience as covering all settings.
  • Pregnancy
  • Gestational age Not reported
  • Postnatal age Not reported
Follow-up Not applicable (recommendation context)
Issued by
World Health Organization
Guideline
WHO recommendations on drug treatment for non-severe hypertension in pregnancy, edition 2020. The WHO publication page shows 11 August 2020; the IRIS record (handle 10665/333816) gives an issue date of 2020-08-13. The text comes from the PDF on IRIS, fetched through the IRIS REST API because the older IRIS bitstream links no longer serve the PDF. Electronic ISBN 978-92-4-000879-3. The guideline predates the CHAP report (2022). Whether WHO has issued a newer recommendation was not checked here.
Strength
Context specific recommendation (WHO guideline method with GRADE. The PDF defines the categories recommended, not recommended, recommended only in specific contexts and recommended only in the context of rigorous research.)
Effective
2020-08-11 (The who.int page date, 11 August 2020 (2020-08-11), is the effective date under the atlas rule for WHO decisions. The WHO IRIS record lists an issue date of 2020-08-13. Both dates are kept.)
Jurisdiction
Global (WHO guideline stated for all settings)
Supersession
Not checked
Basis
WHO recommends offering antihypertensive drug treatment to women with non-severe hypertension during pregnancy, as part of good quality antenatal care follow-up. WHO labels it a context-specific recommendation. WHO’s recommendation table gives no numeric blood-pressure target.

Limitations. Published in 2020, before the CHAP report (2022), so it did not consider CHAP. WHO’s justification says drug treatment probably reduces severe hypertension but may make little or no difference to proteinuria or pre-eclampsia; this is not a GRADE rating of the recommendation, so certainty is not assessed here. WHO also says available evidence suggests calcium channel blockers should be avoided, and its evidence summary lists nifedipine among the calcium channel blockers used in the included trials, while CHAP used extended-release nifedipine as a first-line drug; the atlas records the difference and does not reconcile it. The treatment applies only with regular outpatient monitoring and review.

Clinical links

Each link reports what one cited claim says about one population. "Evaluated for" means studied, not shown to work. These links do not show that anything is effective or right for you.

  • Claim, not a settled fact Evaluated in CHAP against a combined measure of serious pregnancy problems, in women with mild chronic hypertension: Chronic hypertension in pregnancy (Evaluated for)

    Applies to Mixed recipients
    • The same women as the maternal CHAP context, with the outcomes of their pregnancies. The primary composite combines a maternal event (pre-eclampsia with severe features up to 2 weeks after birth), pregnancy events (medically indicated preterm birth before 35 weeks and placental abruption) and a fetal or neonatal event (fetal or neonatal death). It is used only for the composite as the trial defined it and is never split by recipient.
    • Recruiting sites of the CHAP Trial Consortium in the United States; see the maternal CHAP context.
    • United States
    • Pregnancy and the newborn period
    • Gestational age Not reported
    • Postnatal age Not reported
    Follow-up Pre-eclampsia counted up to 2 weeks after birth. Fetal or neonatal death is listed at under 28 days in the manuscript table; the registry gives up to 90 days for neonatal death.
    In the CHAP trial in the United States, women with mild chronic hypertension who enrolled before 23 weeks of pregnancy and were treated to a blood-pressure goal below 140/90 mm Hg had fewer of the combined serious pregnancy problems than women whose treatment was held back unless their blood pressure became severe. The combined outcome (pre-eclampsia with severe features, a medically indicated preterm birth before 35 weeks, placental abruption, or the death of the fetus or newborn) occurred in 353 of 1170 women with outcome data in the treated group (30.2%) and 427 of 1155 in the control group (37.0%). A separate analysis that fills in missing outcomes gave an adjusted risk ratio of 0.82 (95% CI 0.74 to 0.92).

    Limitations. Open-label trial in one country, so women and clinicians knew the assigned strategy. The composite mixes a maternal event with pregnancy events and fetal or neonatal events; the sources do not split it by recipient and the atlas does not either. The percentages and counts come from the complete-case analysis (2325 of 2408 women had enough data); the adjusted risk ratio comes from a multiple-imputation analysis of all 2408. They are different analyses. The authors’ secondary composites of serious maternal complications and of severe neonatal complications did not show clear differences in the abstract; they are about the mother and the newborn separately, so they are not recorded here as claims of their own. Secondary results were not adjusted for multiplicity. For women with newly diagnosed hypertension and for a body-mass index of 40 or more, the risk ratios were close to 1.00 with wide intervals. About 12 women were screened for each woman randomized. The sample size was reduced from a planned 4700 women to a final 2404 that the data and safety monitoring board approved, and the abstract and the Methods word the upper blood-pressure limit differently (below 160/100 vs below 160 and below 105 mm Hg). The registry calls the primary outcome perinatal although it includes a maternal event.

  • Claim, not a settled fact Evaluated in CHAP for pre-eclampsia in women with mild chronic hypertension: Pre-eclampsia (Evaluated for)

    Applies to Maternal
    • Pregnant women with known or new chronic hypertension and a viable singleton fetus before 23 weeks of gestation. Mild means below the severe thresholds, but the sources word the limit differently. The abstract says blood pressure below 160/100 mm Hg. The Methods required, at randomization, a systolic pressure of 140 to 159 or a diastolic pressure of 90 to 104 mm Hg for patients who “had not received an antihypertensive drug within 24 hours before measurement”, and below 160 and below 105 mm Hg for patients who “had been receiving antihypertensive therapy”. Women with lower pressures were also eligible. The registry gives a minimum age of 12 years and adds that the minimum age varies by center; the manuscript states no age limit.
    • Recruiting sites of the CHAP Trial Consortium in the United States. The Methods say more than 70 recruiting sites; the Results say 2419 women were randomized at 61 sites. The manuscript does not say whether the sites were clinics or hospitals.
    • United States
    • Pregnancy, enrolled before 23 weeks of gestation and followed until 6 weeks after birth
    • Gestational age up to 22 weeks 6 days
    • Postnatal age Not reported
    Follow-up Followed until 6 weeks after birth. Pre-eclampsia in the primary composite counted up to 2 weeks after birth.
    In the CHAP trial, any pre-eclampsia (with or without severe features) occurred in 295 of 1208 women in the treated group (24.4%) and 373 of 1200 women in the control group (31.1%), a risk ratio of 0.79 (95% CI 0.69 to 0.89).

    Limitations. This is a secondary outcome, reported without adjustment for multiplicity, so the authors say it should not be used to infer definitive effects. The risk ratio is not described as adjusted in the abstract or the table. The time window for this outcome is not stated in the manuscript text (follow-up ran to 6 weeks after birth; the primary composite counted pre-eclampsia up to 2 weeks after birth). It overlaps with the severe-features part of the primary composite, so the two must not be added. Open-label design, one country.

  • Claim, not a settled fact NICE NG133 1.3.9: target of 135/85 mmHg when medicines are used to treat hypertension in pregnancy: Hypertensive disorders of pregnancy (Recommended for)

    Applies to Maternal
    • Pregnant women with hypertension who are being treated with medicines. The recommendation says hypertension in pregnancy and sits in the NICE section on chronic hypertension. NICE’s management tables for gestational hypertension (recommendation 1.4.3, Table 1) and pre-eclampsia (recommendation 1.5.5, Table 2) also give a target of 135/85 mmHg or less once on treatment. The NG133 Context chapter says the update did not review treatment for the three types of hypertension in pregnancy as one group. NICE defines hypertension as 140 mmHg systolic or higher, or 90 mmHg diastolic or higher, and severe hypertension as over 160 mmHg systolic or over 110 mmHg diastolic.
    • Maternity care; the recommendation does not name a setting.
    • England. NICE's terms and conditions present the information on its websites as support for people in England who make decisions about funding care (clause 6) and say it is not written as a basis for decisions outside the United Kingdom (clause 8). The guideline page states no jurisdiction of its own.
    • Pregnancy
    • Gestational age Not reported
    • Postnatal age Not reported
    Follow-up Not applicable (recommendation context)
    NICE advises that when medicines are used to treat hypertension in pregnancy, the aim is a target blood pressure of 135/85 mmHg. NICE marks this recommendation as one it reviewed in 2019. NICE’s management tables for gestational hypertension and for pre-eclampsia give the same target, 135/85 mmHg or less.

    Limitations. NICE’s target of 135/85 mmHg differs from the goal used in the CHAP trial (below 140/90 mm Hg); the atlas records both and does not reconcile them. This record has not checked whether NICE considered CHAP. The update information lists the April 2023 changes to recommendations 1.3.12 and 1.4.4 only for PlGF-based testing, and does not list 1.3.9. The recommendation sits in the chronic hypertension section while its wording is general; the tables for gestational hypertension and pre-eclampsia carry the same target with the words 135/85 mmHg or less, which 1.3.9 does not use. NICE says its update did not review treatment for the three types of hypertension in pregnancy as one group. NICE gives this recommendation no strength label. The page does not state a jurisdiction; England is inferred from the issuer.

  • Claim, not a settled fact WHO 2020: offer drug treatment when hypertension in pregnancy is non-severe (context-specific recommendation): Hypertensive disorders of pregnancy (Recommended for)

    Applies to Maternal
    • Pregnant women with non-severe hypertension. WHO uses non-severe and mild to moderate interchangeably and defines them as a diastolic pressure of 90 to 109 mmHg and/or a systolic pressure of 140 to 159 mmHg. The recommendation applies in the context of good quality antenatal care follow-up with regular outpatient monitoring and review.
    • Antenatal care with regular outpatient monitoring and review by an antenatal care provider.
    • Global; WHO states the audience as covering all settings.
    • Pregnancy
    • Gestational age Not reported
    • Postnatal age Not reported
    Follow-up Not applicable (recommendation context)
    WHO recommends offering antihypertensive drug treatment to women with non-severe hypertension during pregnancy, as part of good quality antenatal care follow-up. WHO labels it a context-specific recommendation. WHO’s recommendation table gives no numeric blood-pressure target.

    Limitations. Published in 2020, before the CHAP report (2022), so it did not consider CHAP. WHO’s justification says drug treatment probably reduces severe hypertension but may make little or no difference to proteinuria or pre-eclampsia; this is not a GRADE rating of the recommendation, so certainty is not assessed here. WHO also says available evidence suggests calcium channel blockers should be avoided, and its evidence summary lists nifedipine among the calcium channel blockers used in the included trials, while CHAP used extended-release nifedipine as a first-line drug; the atlas records the difference and does not reconcile it. The treatment applies only with regular outpatient monitoring and review.

Record details

Record id
maternal:antihypertensive-treatment-non-severe-hypertension-pregnancy
Content hash
77c860c8e654f1ca23a523ed1334dffe045c9c700bc1983575eb152f04d56183