Primary prevention

Low-dose aspirin (starting between 12 and 28 weeks' gestation, and optimally before 16 weeks' gestation, and continuing until term) reduces the incidence and severity of pre-eclampsia.[1][15][16][41][42][43]​​​ [ Cochrane Clinical Answers logo ] ​​ The effect seems to be uniform across all risk groups, but its use should be targeted at high-risk groups such as those with hypertension, diabetes, renal disease, autoimmune disease, multiple pregnancy, a body mass index of >30, a maternal age of >40 years, or an interval of ≥10 years since previous pregnancy.[8]​​[10][15][16]​​ Meta-analyses of randomised controlled trials suggest that the benefits of aspirin may be limited to prevention of early onset rather than term disease, and only when given at doses of >100 mg/day.[44][45]

It is important to optimise treatment for hypertension and renal disease before pregnancy. Controlled weight loss reduces the incidence of pre-eclampsia.[16] Exercise in pregnancy should be encouraged in the absence of complications, including maternal comorbidities, and risk factors for bleeding or premature delivery. A regular supervised exercise programme may reduce the risk of pre-eclampsia, independently of body mass index.[46][47]

Epidemiological studies have found that low dietary calcium is associated with pre-eclampsia. One Cochrane review found that the addition of high-dose calcium (≥1 g/day) reduced the risk of pre-eclampsia and preterm birth compared with placebo, although the effect was mostly shown in smaller trials, with possible confounding by low dietary calcium intake.[48] In populations in which dietary calcium intake is low, the World Health Organization recommends that pregnant women should receive 1.5 g to 2 g/day of supplementary calcium in order to reduce the severity of pre-eclampsia.[49] However, large, high-quality studies of calcium supplementation from early pregnancy at a range of doses and in different populations are required.[48][49][50][51] [ Cochrane Clinical Answers logo ]

Vitamin D supplementation in pregnancy, with or without additional calcium, may reduce the risk of pre-eclampsia. However, high-quality clinical trials are required to evaluate a range of doses and potential adverse events.[52]

Women with hypertension, including those with an isolated elevated diastolic blood pressure at booking, should be followed up in an increased-frequency surveillance programme.

Secondary prevention

Low-dose aspirin (starting at 12-14 weeks' gestation) is recommended in subsequent pregnancies. If the risk of pre-eclampsia is thought to be high (e.g., previous early-onset disease, severe disease), the benefits are clear. However, they are less clear in mild to moderate or late disease, where the outcome is typically good anyway.[1][7][16]

There is some evidence that low molecular weight heparin, with or without aspirin, might reduce the placental insufficiency in pre-eclampsia, but long-term safety studies are not available.[115][116]

Use of this content is subject to our disclaimer