Table 4.
Screening at study entry and micronutrient supplementation interventions in included studies.
| Reference | Screening for pre-eclampsia | Intervention | Gestational age during intervention |
|---|---|---|---|
| Hofmeyr et al. | Women with previous pre-eclampsia and were intending to become pregnant again |
I = 500 mg of calcium carbonate daily from prepregnancy until 20 weeks’ gestation C = Placebo |
From prepregnancy to 20 weeks’ gestation |
| Baba Dizavandy et al. | Nulliparous women with singleton pregnancies, 24 weeks of gestation, blood pressure <140/90 mmHg, a positive roll-over test and hypocalcuria at 28–32 weeks of pregnancy |
I = 2000 mg of calcium gluconate daily C = Placebo |
From 28–32 weeks gestation to delivery |
| Herrera et al. | First pregnancy, gestation between 28–32 weeks, biopsychosocial risk score of 3 or more, positive roll-over test and high mean arterial pressure |
I = 50 mg of linoleic acid and 600 mg of calcium daily C = Placebo |
From 28–32 weeks’ gestation to delivery |
| Niromanesh et al. | High-risk for pre-eclampsia (identified as having positive results on rollover test and at least one risk factor for pre-eclampsia), gestational age between 28–32 weeks, blood pressure <140/90 mmHg |
I = 2000 mg of calcium daily C = Placebo |
Until delivery |
| Sanchez-Ramos et al. | Normotensive nulliparas at 20–24 weeks’ gestation at increased risk of developing pregnancy-induced hypertension (through positive angiotensin sensitivity test) |
I = 2000 mg of calcium daily C = Placebo |
Not reported |
| Behjat et al. | Pre-eclampsia in previous pregnancy, serum 25-hydroxy vitamin D levels >25 ng/ml |
I = 50000 IU of vitamin D3 every 2 weeks C = Placebo |
Until 36 weeks’ gestation |
| Karamali et al. | Pregnant women primigravida, age of 18–40 and risk of pre-eclampsia (identified through uterine artery Doppler) |
I = 50000 IU of vitamin D3 every 14 days C = Placebo |
From 20 weeks’ to 32 weeks’ gestation |
| Samimi et al. | Primigravida women, aged 18–40 years old, at risk for pre-eclampsia (indicated by laboratory tests including free ß-human chorionic gonadotrophin, inhibin α dimeric, unconjugated oestriol and maternal serum α-foetoprotein and haemodynamic assessment of uterine artery Doppler waveform at 16–20 weeks of gestation) |
I = 50000IU of vitamin D3 every 2 weeks and 1000 mg calcium daily C = Placebo |
From 20 weeks’ to 32 weeks’ gestation |
| Chappell et al. | Women with abnormal two-stage uterine-artery doppler analysis weeks and previous history of pre-eclampsia |
I = 1000 mg of vitamin C and 400 IU of vitamin E daily C = Placebo |
From 16–22 weeks’ gestation (depending on prior history of pre-eclampsia) to delivery |
| Poston et al. | Gestational age 14–21 weeks 6 days and one or more risk factors for pre-eclampsia including pre-eclampsia in the pregnancy preceding the index pregnancy, requiring delivery before 37 completed weeks’ gestation, diagnosis of HELLP syndrome in any previous pregnancy at any stage of gestation, essential hypertension requiring medication currently or previously, maternal diastolic blood pressure of ≥90 mmHg before 20 weeks’ gestation in the current pregnancy, type 1 or type 2 diabetes requiring insulin or oral hypoglycaemic therapy before the pregnancy, antiphospholipid syndrome, chronic renal disease, multiple pregnancy, abnormal uterine artery doppler waveform, primiparity with BMI at first antenatal appointment of ≥30 |
I = 1000 mg of vitamin C and 400IU vitamin E daily C = Placebo |
From 14–21 weeks’ gestation to delivery |
| Spinatto et al. | Pregnant women between 12 and 19 6/7 weeks gestation, non-proteinuric chronic hypertension or with a prior history of preeclampsia in their most recent pregnancy that progressed beyond 20 weeks gestation |
I = 1000 mg of vitamin C and 400IU of vitamin E daily C = Placebo |
From 12–19 weeks’ gestation to delivery |
| Kalpdev et al. | Essential hypertension, singleton pregnancy, gestational age 16 to 22 weeks |
I = 1000 mg of vitamin C and 400IU of vitamin E daily C = No supplementation |
From 16–22 weeks’ gestation to delivery |
| Beazley et al. | Pregnancy at 14–20 weeks and 6 days with a history of previous pre-eclampsia, chronic hypertension, insulin-requiring diabetes or multiple gestation |
I = 1000 mg of vitamin C and 400IU of vitamin E daily C = Placebo |
From 14–20 weeks’ gestation |
| Vadillo-Ortega et al. | Increased risk of pre-eclampsia (history of pre-eclampsia or pre-eclampsia in a first degree relative) |
I = 6.6 g of L-arginine + 500 mg of vitamin C + 400IU of vitamin E daily I2 = 500 mg of vitamin C + 400IU of vitamin E daily C = Placebo |
From 14–32 weeks’ gestation to delivery |
| Villar et al. | Pregnant women 14–22 weeks of gestation and with high risk for pre-eclampsia (chronic hypertension, renal disease, pre-eclampsia-eclampsia in the pregnancy preceding the index pregnancy requiring delivery before 37 weeks’ gestation, HELLP syndrome in any previous pregnancy, pregestational diabetes, primiparous with a BMI ≥ 30, history of preterm delivery, abnormal uterine artery Doppler waveforms and women with antiphospholipid syndrome) |
I = 1000 mg of vitamin C and 400IU of vitamin E daily C = Placebo |
14–22 weeks’ gestation to delivery |
| Zheng et al. | Previous pre-eclampsia, planning pregnancy, aged over 18 years, daily folic acid intake before randomization <1.1 mg |
C = Low dose folic acid (0.4 mg) daily I = High dose folic acid (4 mg) daily |
Preconception to delivery |
| Wen et al. | Pregnant women between 8–16 completed weeks of gestation and at least one risk factor for pre-eclampsia including pre-existing hypertension, prepregnancy diabetes (type 1 or 2), twin pregnancy, pre-eclampsia in a previous pregnancy or BMI ≥ 35 |
I = 4 mg of folic acid daily C = Placebo |
From 8–16 weeks’ gestation to delivery |
| De Araujo et al. | Women aged 18 to 45 years, 12 to 20 weeks of gestation, singleton pregnancy and ≥1 risk factor for preterm birth or adverse perinatal outcomes in a prior pregnancy (i.e. preterm delivery <37 weeks, still birth at 201/7 weeks, placental abruption, pre-eclampsia or eclampsia, a live-born infant with SGA birthweight <3rd percentile or liveborn infant with birthweight <2500 g) or in current pregnancy (i.e. nulliparity, chronic hypertension, type 1 or 2 diabetes mellitus, maternal age >35 years, pre-pregnancy BMI > 30 or smoking) |
I = 300 mg of magnesium citrate daily C = Placebo |
From 12–20 weeks’ gestation to delivery |
| Azami et al. | Women with at least one risk factor for pre-eclampsia (including chronic vascular disease, hydatidiform mole, multiparity, diabetes mellitus, thyroid disease, chronic hypertension, nulliparity, history of pre-eclampsia, maternal age >35 years, kidney disease, collagen vascular disease, antiphospholipid antibody syndrome, family history of pre-eclampsia, history of thrombophilia and BMI > 25) |
I1 = Ferrous sulfate tablet + one multimineral vitamin D tablet containing 800 mg of calcium, 8 mg of zinc and 400IU of vitamin D3 daily I2 = Ferrous sulfate tablet + 250 mg of vitamin C and 55 mg of vitamin E daily C = Ferrous sulfate tablet daily |
From 20 weeks’ gestation to delivery |
| Parrish et al. |
For low risk group: nulliparous or multiparous women, singleton gestation and no evidence of systemic vascular disease For high risk group: multiparous patients with singleton gestation and a prior history of preeclampsia (prior eclampsia, prior mild or severe preeclampsia, prior HELLP) or nulliparous/multiparous patients with singleton gestation with a documented history of chronic hypertension, diabetes mellitus, connective tissue disease or inherited/acquired thrombophilia |
I = Phytonutrients (7.5 mg beta-carotene, 234 mg vitamin C, 30 mg vitamin E, 420 mg folate and 60 mg calcium - mix through a concentrate of blended fruit and vegetable juice powder) taken twice daily until delivery C = Placebo |
Any time up to 12 weeks’ gestation until delivery |