Pre-eclampsia

A condition of pregnancy in which blood pressure rises after 20 weeks and, at the same time, there are signs that other parts of the body are affected. These can include protein in the urine, or problems with the kidneys, liver, blood or brain, or with the placenta and the baby’s growth.

Also called Preeclampsia

Condition
In this atlas

Overview

Technical summary

NICE NG133 (terms used) defines it as high blood pressure first seen after 20 weeks of pregnancy, above 140 mmHg systolic or above 90 diastolic, together with at least one new problem: protein in the urine, or dysfunction of the kidneys, liver, nervous system or blood, or of the uteroplacental unit (for example poor fetal growth, abnormal umbilical artery doppler results or stillbirth). Other guidelines and trials define it differently; the CHAP trial used ACOG criteria, and this atlas has not compared the two. Pre-eclampsia can develop in women who have chronic hypertension (NG133 1.3.12; CHAP registry description). The recipient is the pregnant woman; fetal and newborn consequences sit in claims with their own contexts.

Burden

No burden claims are published.

Claims and evidence

No claims are published for this condition yet.

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 for this: Antihypertensive drug treatment for non-severe hypertension in pregnancy (Evaluated for, seen from the other side)
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 Recommended for this: Low-dose aspirin to prevent pre-eclampsia (Recommended for, seen from the other side)
Applies to Maternal
- Pregnant women at high risk of pre-eclampsia, which NICE defines as having any one of five listed factors.
- 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.
- 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.
- Pregnancy, from 12 weeks until the baby is born
- Gestational age at least 12 weeks 0 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.
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.
Claim, not a settled fact Recommended for this: Low-dose aspirin to prevent pre-eclampsia (Recommended for, seen from the other side)
Applies to Maternal
- Pregnant women who have more than one of six moderate risk factors for pre-eclampsia that NICE lists.
- 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.
- 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.
- Pregnancy, from 12 weeks until the baby is born
- Gestational age at least 12 weeks 0 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.
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.
Claim, not a settled fact Recommended for this: PlGF-based testing for suspected preterm pre-eclampsia (Recommended for, seen from the other side)
Applies to Maternal
- People with suspected preterm pre-eclampsia between 20 weeks and 36 weeks and 6 days of pregnancy. NICE treats a woman who meets only part of the pre-eclampsia criteria as having suspected pre-eclampsia.
- Not stated as a setting. The guidance is for the NHS and describes testing used with standard clinical assessment.
- England (NHS). 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 guidance page states no jurisdiction of its own. The guidance refers to routine use in the NHS.
- Pregnancy, 20 weeks to 36 weeks and 6 days
- Gestational age 20 weeks 0 days to 36 weeks 6 days
- Postnatal age Not reported
Follow-up Not applicable (recommendation context)
NICE recommends four named tests that are based on placental growth factor (PLGF). They are to be used alongside the usual clinical assessment, as an aid to ruling pre-eclampsia in or out in people who are suspected of having preterm pre-eclampsia at 20 weeks to 36 weeks and 6 days of pregnancy, so that decisions about care can be made. The four tests are DELFIA Xpress PLGF 1-2-3, DELFIA Xpress sFlt-1/PLGF 1-2-3 ratio, Elecsys immunoassay sFlt-1/PLGF ratio and Triage PLGF Test. NICE adds that each test is to be used within its manufacturer's stated indications for use, and adds that some manufacturers do not indicate their tests for the whole gestational range.
Limitations. NICE recommends against using the tests to guide the decision on whether a planned early birth should be offered to people with preterm pre-eclampsia (recommendation 1.4), and recommends using a test once for each episode of suspected preterm pre-eclampsia (recommendation 1.5). NICE also does not recommend a fifth test, the BRAHMS sFlt-1 Kryptor/BRAHMS PLGF plus Kryptor PE ratio, for routine NHS use (recommendation 1.6). That statement is kept here and not as a separate recommendation, because no product record exists for that test. The recommendation is NICE's for the NHS and is not the US FDA-cleared use of the Elecsys test. The page gives no strength grade or certainty rating, and no performance figures are recorded here. The guidance was migrated from diagnostics guidance 49 with its content unchanged. Only the NICE pages read on 2026-10-11 were checked for a later edition.
Claim, not a settled fact Evaluated for this: Elecsys sFlt-1 and Elecsys PlGF (Roche) (Evaluated for, seen from the other side)
Applies to Maternal
- Pregnant women with a singleton pregnancy, hospitalized for a hypertensive disorder of pregnancy (pre-eclampsia, chronic hypertension with or without superimposed pre-eclampsia, or gestational hypertension), at 23 weeks 0 days to 34 weeks 6 days.
- Hospital. The indication is for women hospitalized for the disorder.
- United States (FDA labelling)
- Pregnancy, 23 weeks 0 days to 34 weeks 6 days
- Gestational age 23 weeks 0 days to 34 weeks 6 days
- Postnatal age Not reported
Follow-up Two weeks from testing, the window in the indication for developing pre-eclampsia with severe features
Roche's 510(k) summary for K241453 reports the PRAECIS study, which validated a cut-off of 38 for the Elecsys sFlt-1/PlGF ratio as an aid in judging which hospitalized pregnant women with a hypertensive disorder would develop pre-eclampsia with severe features within two weeks of testing. Of 556 women, 186 developed it and 370 did not. Sensitivity was 91.40% (95% confidence interval 86.41 to 95.00) and specificity 77.30% (72.68 to 81.47). The negative predictive value was 94.70% (91.54 to 96.94) and the positive predictive value 66.93% (60.77 to 72.68). The prevalence in the study was 33.45%.
Limitations. These figures are the submitter's, from one study reported in a regulatory summary. No peer-reviewed paper on PRAECIS was read. The predictive values depend on the 33.45% prevalence of pre-eclampsia with severe features in this hospitalized population and would differ in other populations. In the table, 84 women above the cut-off did not develop pre-eclampsia with severe features within two weeks, and 16 women at or below it did. The summary says the performance criteria for negative and positive predictive value were met. The summary does not state the criteria, the study design, the sites or the dates, or how the outcome was judged. The cut-off of 38 here belongs to the US prognostic use only. The table values were checked against the page image of the PDF.
Claim, not a settled fact Risk raised by: Nulliparity (Associated with a higher risk of, seen from the other side)
Applies to Maternal
- Pregnant women with nulliparity, one of six factors that NICE lists as indicating moderate risk of pre-eclampsia. The NICE page does not define nulliparity.
- Not stated in the source.
- 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. The source gives no gestational age for the risk factor itself.
- Gestational age Not reported
- Postnatal age Not reported
Follow-up Not applicable (risk factor context)
NICE lists nulliparity as one of six factors that indicate moderate risk of pre-eclampsia, alongside 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. NICE advises aspirin for women who have more than one of these factors.
Limitations. NICE does not say how much nulliparity raises the risk by itself, and the NICE page does not define the term, so no risk figure is recorded. In August 2022 NICE corrected the wording of recommendation 1.1.3 from first pregnancy to nulliparity, so the two terms must not be used as if they meant the same. WHO 2021 uses a different term, primiparity, in its own moderate-risk list. A list of risk factors is not an estimate of risk for any one woman.

Record details

Record id: maternal:preeclampsia
Content hash: 07e0683e785a13af76a84b592d42b5f5b7161136b122e1cd7ec4e2da6566dfb5