What do systematic reviews say?

Technique of BP measurement: Korotkoff phase IV vs Korotkoff phase V to represent diastolic BP

Technique of BP measurement: Korotkoff phase IV showed no clear difference in pre‐eclampsia compared with korotkoff phase V to represent diastolic BP (low certainty).

• Setting and techniques for monitoring blood pressure during pregnancy 2020 · Cochrane Headline outcomes only
  RR 1.16 [0.89, 1.49]
  1 study · 220 participants
  Low

Technique of BP measurement: CRADLE intervention vs usual care

The review found no eligible studies for this question.

• Setting and techniques for monitoring blood pressure during pregnancy 2020 · Cochrane Headline outcomes only
  no estimate extracted
  Studies not reported
  No studies found

Setting of BP measurement: self‐measurement vs conventional clinic measurement

Setting of BP measurement: self‐measurement showed no clear difference in pre‐eclampsia compared with conventional clinic measurement (low certainty).

• Setting and techniques for monitoring blood pressure during pregnancy 2020 · Cochrane Headline outcomes only
  RR 1.49 [0.87, 2.54]
  1 study · 154 participants
  Low

Heparin plus aspirin vs aspirin

Heparin plus aspirin showed no clear difference in pre‐eclampsia compared with aspirin (low certainty).

• Aspirin or heparin or both for improving pregnancy outcomes in women with persistent antiphospholipid antibodies and… 2020 · Cochrane Headline outcomes only
  RR 0.57 [0.1, 3.14]
  2 studies · 82 participants
  Low

Aspirin vs placebo

It is very uncertain whether aspirin changes pre‐eclampsia compared with placebo (very low certainty).

• Aspirin or heparin or both for improving pregnancy outcomes in women with persistent antiphospholipid antibodies and… 2020 · Cochrane Headline outcomes only
  RR 1.06 [0.25, 4.52]
  1 study · 33 participants
  Very low

Vitamin D vs placebo or no intervention

Vitamin D supplementation probably leads to lower pre‐eclampsia compared with placebo or no intervention (moderate certainty).

• Vitamin D supplementation for women during pregnancy 2019 · Cochrane Headline outcomes only
  RR 0.48 [0.3, 0.79]
  4 studies · 499 participants
  Moderate

Vitamin D + calcium + other vitamins and minerals vs calcium + other vitamins and minerals (but no vitamin D)

• Vitamin D supplementation for women during pregnancy 2019 · Cochrane Headline outcomes only
  no estimate extracted
  0 studies · 0 participants
  GRADE not reported

Vitamin D plus calcium vs placebo or no intervention

Vitamin D + calcium supplementation probably leads to lower pre‐eclampsia compared with placebo or no intervention (moderate certainty).

• Vitamin D supplementation for women during pregnancy 2019 · Cochrane Headline outcomes only
  RR 0.5 [0.32, 0.78]
  4 studies · 1174 participants
  Moderate

Calcium supplementation/fortification vs placebo (outcomes

Calcium supplementation showed no clear difference in pre‐eclampsia compared with placebo (maternal outcomes) commencing before or early (low certainty).

• Calcium supplementation commencing before or early in pregnancy, for preventing hypertensive disorders of pregnancy 2019 · Cochrane Headline outcomes only
  RR 0.8 [0.61, 1.06]
  1 study · 579 participants
  Low

A dose of vitamin D 601 IU or higher vs 600 IU or lower alone or with other nutrients

A dose of vitamin D 601 IU or higher showed no clear difference in pre‐eclampsia compared with 600 IU or lower alone or with other nutrients (low certainty).

• Regimens of vitamin D supplementation for women during pregnancy 2019 · Cochrane Headline outcomes only
  RR 0.96 [0.65, 1.42]
  5 studies · 1553 participants
  Low

A dose of vitamin D 4000 IU/d or more vs 3999 IU/d or less alone or with any other nutrient

A dose of vitamin D 4000 IU/d or more showed no clear difference in pre‐eclampsia compared with 3999 IU/d or less alone or with any other nutrient (low certainty).

• Regimens of vitamin D supplementation for women during pregnancy 2019 · Cochrane Headline outcomes only
  RR 0.87 [0.62, 1.22]
  4 studies · 1903 participants
  Low

Intervention not reported

The intervention may leads to lower pre‐eclampsia (low certainty).

• Calcium supplementation during pregnancy for preventing hypertensive disorders and related problems 2018 · Cochrane Headline outcomes only
  RR 0.45 [0.31, 0.65]
  13 studies · 15730 participants
  Low

Intervention not reported

The intervention showed no clear difference in pre‐eclampsia (low certainty).

• Omega‐3 fatty acid addition during pregnancy 2018 · Cochrane Headline outcomes only
  RR 0.84 [0.69, 1.01]
  20 studies · 8306 participants
  Low

Metformin vs placebo

Metformin showed no clear difference in pre‐eclampsia compared with placebo (low certainty).

• Metformin for women who are overweight or obese during pregnancy for improving maternal and infant outcomes 2018 · Cochrane Headline outcomes only
  RR 0.74 [0.09, 6.28]
  2 studies · 840 participants
  Low

Human insulin vs animal insulin (Different insulin types within similar insulin regimens)

• Different insulin types and regimens for pregnant women with pre‐existing diabetes 2017 · Cochrane Headline outcomes only
  no estimate extracted
  0 studies · 0 participants
  GRADE not reported

Pre‐mixed insulin (70 NPH/30 REG) vs self‐mixed split dose insulin (Different insulin regimens with similar insulin types used within the regimen)

• Different insulin types and regimens for pregnant women with pre‐existing diabetes 2017 · Cochrane Headline outcomes only
  no estimate extracted
  0 studies · 0 participants
  GRADE not reported

Insulin injected with a Novolin pen vs insulin injected with a needle or syringe (Different insulin regimens with similar insulin types used within the regimen)

• Different insulin types and regimens for pregnant women with pre‐existing diabetes 2017 · Cochrane Headline outcomes only
  no estimate extracted
  0 studies · 0 participants
  GRADE not reported

Lispro vs regular insulin (Different insulin types within similar insulin regimens)

It is very uncertain whether lispro changes pre‐eclampsia compared with regular insulin (Different insulin types within similar insulin… (very low certainty).

• Different insulin types and regimens for pregnant women with pre‐existing diabetes 2017 · Cochrane Headline outcomes only
  RR 0.68 [0.35, 1.3]
  1 study · 33 participants
  Very low

Insulin Aspart (+ NPH) vs human insulin (+ NPH insulin)

The review found no eligible studies for this question.

• Different insulin types and regimens for pregnant women with pre‐existing diabetes 2017 · Cochrane Headline outcomes only
  no estimate extracted
  Studies not reported
  No studies found

Insulin Detemir + prandial insulin Aspart vs NPH insulin + prandial insulin Aspart (Different insulin types within similar insulin regimens)

• Different insulin types and regimens for pregnant women with pre‐existing diabetes 2017 · Cochrane Headline outcomes only
  no estimate extracted
  0 studies · 0 participants
  GRADE not reported