# Low-dose aspirin to prevent pre-eclampsia Intervention · id `maternal:low-dose-aspirin-preeclampsia-prevention` · Maternal & Newborn Atlas · release `15708f235d73cd42` (public) > General information from published sources, not medical advice, and not reviewed by clinicians. Check the cited source before relying on anything here. The atlas's own text and curation may be reused under Creative Commons Attribution-NonCommercial 4.0 International (CC BY-NC 4.0, https://creativecommons.org/licenses/by-nc/4.0/): credit the atlas, and do not use it commercially. See the atlas About page. Text quoted from a source stays under that source's own terms, given as the source's reuse\_basis. The atlas's reuse terms do not cover it. The downloads list each quotation with its source in third\_party\_quotations. Browse, life stage: Pregnancy ## In plain language A small daily dose of aspirin taken during pregnancy by women at higher risk of pre-eclampsia, to help prevent it. In England, NICE tells clinicians to advise 75 mg to 150 mg a day, from 12 weeks of pregnancy until the birth, for women at high risk and for women with more than one moderate risk factor. NICE notes that for this use aspirin has to be prescribed, and that community pharmacies in England may not lawfully sell aspirin for pre-eclampsia prevention as a pharmacy medicine. WHO gives different advice: 75 mg a day for women at moderate or high risk, using its own lists of risk factors. ## Technical summary Aspirin (acetylsalicylic acid) at 75 mg to 150 mg daily from week 12 of pregnancy to the birth, as in NICE NG133 recommendations 1.1.2 and 1.1.3, both marked \[2010, amended 2019\]. The NICE page notes that at publication in June 2019 aspirin had no UK marketing authorisation, and says that community pharmacies in England may not lawfully sell aspirin for pre-eclampsia prevention as a pharmacy medicine, and that aspirin for this use must be prescribed. A recommendation is not an authorization. WHO 2021 recommends 75 mg per day for women at moderate or high risk and says treatment should start by 20 weeks or as soon as antenatal care starts (WHO labels this a "Context-specific recommendation"). The risk lists, doses and start times differ between issuers, so each is kept in its own claim and context. NICE NG133 gives no effect size; this record does not state one. ## Claims, with the population each applies to ## Context: Pregnant women at high risk of pre-eclampsia (NICE NG133 recommendation 1.1.2) Recipient: Maternal; Population: Pregnant women at high risk of pre-eclampsia, which NICE defines as having any one of five listed factors.; Care setting: Not stated in the source beyond two notes: community pharmacies in England may not lawfully sell aspirin for pre-eclampsia prevention as a pharmacy medicine, and aspirin for this use must be prescribed.; Geography: England. NICE's terms and conditions present the information on its websites as support for people in England (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, from 12 weeks until the baby is born; Gestational age: at least 12 weeks 0 days (84 days); Postnatal age: Not reported; Follow-up: Not applicable (recommendation context) ### NICE tells clinicians to advise women who are pregnant and at high risk of pre-eclampsia to take aspirin every day at a dose of 75 mg to 150 mg, from 12 weeks of pregnancy until the baby is born. High risk means having any one of five listed factors: hypertensive disease in a previous pregnancy, chronic kidney disease, autoimmune disease such as systemic lupus erythematosus or antiphospholipid syndrome, type 1 or type 2 diabetes, or chronic hypertension. - Category: Recommendation - Evidence stage: Guidance - Certainty: Certainty not assessed - Applies to: Recipient: Maternal; Population: Pregnant women at high risk of pre-eclampsia, which NICE defines as having any one of five listed factors.; Care setting: Not stated in the source beyond two notes: community pharmacies in England may not lawfully sell aspirin for pre-eclampsia prevention as a pharmacy medicine, and aspirin for this use must be prescribed.; Geography: England. NICE's terms and conditions present the information on its websites as support for people in England (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, from 12 weeks until the baby is born; Gestational age: at least 12 weeks 0 days (84 days); Postnatal age: Not reported; Follow-up: Not applicable (recommendation context) - Limitations: This is a guideline recommendation, not a marketing authorisation. The NICE page says that at publication in June 2019 aspirin had no UK marketing authorisation for this use, and that community pharmacies in England may not lawfully sell aspirin for pre-eclampsia prevention as a pharmacy medicine, and also that aspirin for this use must be prescribed. The page gives no strength grade, no certainty rating and no effect size for this advice, so none is recorded. The dose range, the start time and the risk list are NICE's. WHO 2021 recommends 75 mg per day for women at moderate or high risk, with different risk lists, and says to start by 20 weeks or as soon as antenatal care starts (WHO labels this a "Context-specific recommendation"), so the advice differs between issuers. Do not apply this claim outside the NICE context. - Last checked: 2026-10-12 - Sources: 1. Supports: Hypertension in pregnancy: diagnosis and management (NICE guideline NG133), Recommendations chapter (Guideline, 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.) Locator: 1.1.2, first sentence and lead-in to the list. Retrieved 2026-10-11T18:19:40Z. Source state: Current. Snapshot hash: 0cd8548f5807f03a82b3101dc56ebadf674106da9d0aa7e57955d4a823556fca. How it applies: NICE NG133, cited and linked only. The dose, the start time and the end point. 2. Supports: Hypertension in pregnancy: diagnosis and management (NICE guideline NG133), Recommendations chapter (Guideline, 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.) Locator: 1.1.2, high-risk list and recommendation tag. Retrieved 2026-10-11T18:19:40Z. Source state: Current. Snapshot hash: 0cd8548f5807f03a82b3101dc56ebadf674106da9d0aa7e57955d4a823556fca. How it applies: The five factors that define high risk, and the tag \[2010, amended 2019\]. 3. Background: Hypertension in pregnancy: diagnosis and management (NICE guideline NG133), Recommendations chapter (Guideline, 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.) Locator: Antiplatelet agents, note before 1.1.2. Retrieved 2026-10-11T18:19:40Z. Source state: Current. Snapshot hash: 0cd8548f5807f03a82b3101dc56ebadf674106da9d0aa7e57955d4a823556fca. How it applies: Marketing authorisation status in the UK at June 2019, and the need for a prescription. 4. Background: Hypertension in pregnancy: diagnosis and management (NICE guideline NG133), Update information chapter (Guideline, 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.) Locator: June 2019 update, changes made without an evidence review. Retrieved 2026-10-11T19:16:21Z. Source state: Current. Snapshot hash: 248348547ec88c3384b6fb76489a433766acf40e47b5f77d8060516561836a58. How it applies: NICE says it amended the aspirin dose information in June 2019 without an evidence review. 5. Background: WHO recommendations on antiplatelet agents for the prevention of pre-eclampsia (Guideline, edition 2021, electronic edition. The PDF (81 pages) came from WHO IRIS handle 10665/350190 through the IRIS REST API content endpoint (bitstream 76d9febc-540a-4a2e-8664-237f523a3e47), because the older apps.who.int links no longer return the PDF. The who.int publication page supplied the date.) Locator: Table 1, recommendation. Retrieved 2026-10-11T19:15:07Z. Source state: Current. Snapshot hash: 98c96df70c4a3ad168f56ffcea73cd3cba2626474ff0e541412f7c81704eadd3. How it applies: WHO 2021, a different issuer with a different dose and risk lists. Shown to mark that issuers differ, not to support the NICE advice. 6. Background: WHO recommendations on antiplatelet agents for the prevention of pre-eclampsia (Guideline, edition 2021, electronic edition. The PDF (81 pages) came from WHO IRIS handle 10665/350190 through the IRIS REST API content endpoint (bitstream 76d9febc-540a-4a2e-8664-237f523a3e47), because the older apps.who.int links no longer return the PDF. The who.int publication page supplied the date.) Locator: Table 2, recommendation. Retrieved 2026-10-11T19:15:07Z. Source state: Current. Snapshot hash: 98c96df70c4a3ad168f56ffcea73cd3cba2626474ff0e541412f7c81704eadd3. How it applies: WHO 2021 start time, which differs from the NICE start time. ## Context: Pregnant women with more than one moderate risk factor for pre-eclampsia (NICE NG133 recommendation 1.1.3) Recipient: Maternal; Population: Pregnant women who have more than one of six moderate risk factors for pre-eclampsia that NICE lists.; Care setting: Not stated in the source beyond two notes: community pharmacies in England may not lawfully sell aspirin for pre-eclampsia prevention as a pharmacy medicine, and aspirin for this use must be prescribed.; Geography: England. NICE's terms and conditions present the information on its websites as support for people in England (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, from 12 weeks until the baby is born; Gestational age: at least 12 weeks 0 days (84 days); Postnatal age: Not reported; Follow-up: Not applicable (recommendation context) ### NICE tells clinicians to advise women who are pregnant and have more than one moderate risk factor for pre-eclampsia to take aspirin every day at a dose of 75 mg to 150 mg, from 12 weeks of pregnancy until the baby is born. The six moderate risk factors are nulliparity, age 40 years or older, a pregnancy interval of more than 10 years, a body mass index of 35 kg/m2 or more at the first visit, a family history of pre-eclampsia and a multi-fetal pregnancy. - Category: Recommendation - Evidence stage: Guidance - Certainty: Certainty not assessed - Applies to: Recipient: Maternal; Population: Pregnant women who have more than one of six moderate risk factors for pre-eclampsia that NICE lists.; Care setting: Not stated in the source beyond two notes: community pharmacies in England may not lawfully sell aspirin for pre-eclampsia prevention as a pharmacy medicine, and aspirin for this use must be prescribed.; Geography: England. NICE's terms and conditions present the information on its websites as support for people in England (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, from 12 weeks until the baby is born; Gestational age: at least 12 weeks 0 days (84 days); Postnatal age: Not reported; Follow-up: Not applicable (recommendation context) - Limitations: This is a guideline recommendation, not a marketing authorisation. The NICE page says that at publication in June 2019 aspirin had no UK marketing authorisation for this use, and that community pharmacies in England may not lawfully sell aspirin for pre-eclampsia prevention as a pharmacy medicine, and also that aspirin for this use must be prescribed. The page gives no strength grade, no certainty rating and no effect size, so none is recorded. A single moderate factor does not meet the NICE advice; the advice needs more than one. WHO 2021 recommends 75 mg per day for women at moderate or high risk and defines moderate risk as any two of its own list, which includes primiparity rather than nulliparity, so the issuers differ in dose, risk list and start time. Do not apply this claim outside the NICE context. - Last checked: 2026-10-12 - Sources: 1. Supports: Hypertension in pregnancy: diagnosis and management (NICE guideline NG133), Recommendations chapter (Guideline, 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.) Locator: 1.1.3, first sentence and lead-in to the list. Retrieved 2026-10-11T18:19:40Z. Source state: Current. Snapshot hash: 0cd8548f5807f03a82b3101dc56ebadf674106da9d0aa7e57955d4a823556fca. How it applies: NICE NG133, cited and linked only. The dose, the start time and the number of factors needed. 2. Supports: Hypertension in pregnancy: diagnosis and management (NICE guideline NG133), Recommendations chapter (Guideline, 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.) Locator: 1.1.3, moderate-risk list, items 1 to 3. Retrieved 2026-10-11T18:19:40Z. Source state: Current. Snapshot hash: 0cd8548f5807f03a82b3101dc56ebadf674106da9d0aa7e57955d4a823556fca. How it applies: The first three of the six moderate risk factors, beginning with nulliparity. 3. Supports: Hypertension in pregnancy: diagnosis and management (NICE guideline NG133), Recommendations chapter (Guideline, 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.) Locator: 1.1.3, moderate-risk list, items 4 to 6 and recommendation tag. Retrieved 2026-10-11T18:19:40Z. Source state: Current. Snapshot hash: 0cd8548f5807f03a82b3101dc56ebadf674106da9d0aa7e57955d4a823556fca. How it applies: The last three moderate risk factors, and the tag \[2010, amended 2019\]. 4. Background: Hypertension in pregnancy: diagnosis and management (NICE guideline NG133), Recommendations chapter (Guideline, 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.) Locator: Antiplatelet agents, note before 1.1.2. Retrieved 2026-10-11T18:19:40Z. Source state: Current. Snapshot hash: 0cd8548f5807f03a82b3101dc56ebadf674106da9d0aa7e57955d4a823556fca. How it applies: Marketing authorisation status in the UK at June 2019, and the need for a prescription. 5. Background: Hypertension in pregnancy: diagnosis and management (NICE guideline NG133), Update information chapter (Guideline, 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.) Locator: June 2019 update, changes made without an evidence review. Retrieved 2026-10-11T19:16:21Z. Source state: Current. Snapshot hash: 248348547ec88c3384b6fb76489a433766acf40e47b5f77d8060516561836a58. How it applies: NICE says it amended the aspirin dose information in June 2019 without an evidence review. 6. Background: WHO recommendations on antiplatelet agents for the prevention of pre-eclampsia (Guideline, edition 2021, electronic edition. The PDF (81 pages) came from WHO IRIS handle 10665/350190 through the IRIS REST API content endpoint (bitstream 76d9febc-540a-4a2e-8664-237f523a3e47), because the older apps.who.int links no longer return the PDF. The who.int publication page supplied the date.) Locator: Table 1, recommendation. Retrieved 2026-10-11T19:15:07Z. Source state: Current. Snapshot hash: 98c96df70c4a3ad168f56ffcea73cd3cba2626474ff0e541412f7c81704eadd3. How it applies: WHO 2021, a different issuer with a different dose. Shown to mark that issuers differ. 7. Background: WHO recommendations on antiplatelet agents for the prevention of pre-eclampsia (Guideline, edition 2021, electronic edition. The PDF (81 pages) came from WHO IRIS handle 10665/350190 through the IRIS REST API content endpoint (bitstream 76d9febc-540a-4a2e-8664-237f523a3e47), because the older apps.who.int links no longer return the PDF. The who.int publication page supplied the date.) Locator: Table 1, remarks, bullet 2. Retrieved 2026-10-11T19:15:07Z. Source state: Current. Snapshot hash: 98c96df70c4a3ad168f56ffcea73cd3cba2626474ff0e541412f7c81704eadd3. How it applies: WHO's moderate-risk rule: any two of a list that names primiparity. 8. Background: WHO recommendations on antiplatelet agents for the prevention of pre-eclampsia (Guideline, edition 2021, electronic edition. The PDF (81 pages) came from WHO IRIS handle 10665/350190 through the IRIS REST API content endpoint (bitstream 76d9febc-540a-4a2e-8664-237f523a3e47), because the older apps.who.int links no longer return the PDF. The who.int publication page supplied the date.) Locator: Table 2, recommendation. Retrieved 2026-10-11T19:15:07Z. Source state: Current. Snapshot hash: 98c96df70c4a3ad168f56ffcea73cd3cba2626474ff0e541412f7c81704eadd3. How it applies: WHO 2021 start time, which differs from the NICE start time. ## Guidance, authorization and access ### Recommendation `maternal:rec-nice-ng133-1-1-2` - Intervention: Low-dose aspirin to prevent pre-eclampsia (`maternal:low-dose-aspirin-preeclampsia-prevention`) - Direction: Recommended - Issued by: National Institute for Health and Care Excellence (NICE) (`maternal: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.; snapshot `maternal:nice-ng133-recs-2026-10-11` - 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. - Strength: Advise (no graded strength label on the page) (NICE guideline wording, in which the verb shows the strength of a recommendation. The page points to a separate NICE document that explains how, and gives no GRADE rating for this recommendation.) - Effective: 2019-06-25 (The recommendation is tagged \[2010, amended 2019\]. 25 June 2019 is the guideline's publication date, which is when the 2019 amendments were made. The page was last updated on 17 April 2023 for other recommendations.) - Supersession: Not checked - Applies to: Recipient: Maternal; Population: Pregnant women at high risk of pre-eclampsia, which NICE defines as having any one of five listed factors.; Care setting: Not stated in the source beyond two notes: community pharmacies in England may not lawfully sell aspirin for pre-eclampsia prevention as a pharmacy medicine, and aspirin for this use must be prescribed.; Geography: England. NICE's terms and conditions present the information on its websites as support for people in England (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, from 12 weeks until the baby is born; Gestational age: at least 12 weeks 0 days (84 days); Postnatal age: Not reported; Follow-up: Not applicable (recommendation context) - Basis: claim `maternal:claim-nice-ng133-1-1-2-aspirin-high-risk` ### Recommendation `maternal:rec-nice-ng133-1-1-3` - Intervention: Low-dose aspirin to prevent pre-eclampsia (`maternal:low-dose-aspirin-preeclampsia-prevention`) - Direction: Recommended - Issued by: National Institute for Health and Care Excellence (NICE) (`maternal: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.; snapshot `maternal:nice-ng133-recs-2026-10-11` - 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. - Strength: Advise (no graded strength label on the page) (NICE guideline wording, in which the verb shows the strength of a recommendation. The page points to a separate NICE document that explains how, and gives no GRADE rating for this recommendation.) - Effective: 2019-06-25 (The recommendation is tagged \[2010, amended 2019\]. 25 June 2019 is the guideline's publication date, which is when the 2019 amendments were made. The page was last updated on 17 April 2023 for other recommendations. Wording corrected in August 2022 (first pregnancy to nulliparity); the effective date stays 2019-06-25.) - Supersession: Not checked - Applies to: Recipient: Maternal; Population: Pregnant women who have more than one of six moderate risk factors for pre-eclampsia that NICE lists.; Care setting: Not stated in the source beyond two notes: community pharmacies in England may not lawfully sell aspirin for pre-eclampsia prevention as a pharmacy medicine, and aspirin for this use must be prescribed.; Geography: England. NICE's terms and conditions present the information on its websites as support for people in England (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, from 12 weeks until the baby is born; Gestational age: at least 12 weeks 0 days (84 days); Postnatal age: Not reported; Follow-up: Not applicable (recommendation context) - Basis: claim `maternal:claim-nice-ng133-1-1-3-aspirin-moderate-risk` ## Connected pages - NICE NG133 1.1.2: 75 to 150 mg daily from 12 weeks for women at high risk (any one of five listed factors): Pre-eclampsia (`maternal:preeclampsia`) [a claim, not a settled fact; see claim `maternal:claim-nice-ng133-1-1-2-aspirin-high-risk` and its context] - NICE NG133 1.1.3: 75 to 150 mg daily from 12 weeks for women with more than one of six moderate risk factors: Pre-eclampsia (`maternal:preeclampsia`) [a claim, not a settled fact; see claim `maternal:claim-nice-ng133-1-1-3-aspirin-moderate-risk` and its context] ## Provenance Content hash: 6c5027ade91c223ec29d8f9165c094ae3be1c354fe5c39c2c6157041546f0751 Last substantive edit: 2026-10-13 Evidence last checked: 2026-10-12