Vitamin C and vitamin E showed no clear difference in early or late miscarriage compared with placebo (moderate certainty).
Vitamin C and vitamin E showed no clear difference in stillbirth compared with placebo (moderate certainty).
Vitamin D supplementation probably leads to lower pre‐eclampsia compared with placebo or no intervention (moderate certainty).
Vitamin D supplementation probably leads to lower gestational diabetes compared with placebo or no intervention (moderate certainty).
Vitamin D supplementation may leads to lower maternal adverse events: severe postpartum haemorrhage compared with placebo or no intervention (low certainty).
It is very uncertain whether vitamin D supplementation changes maternal adverse event: nephritic syndrome compared with placebo or no intervention (very low certainty).
Vitamin D supplementation showed no clear difference in preterm birth (less than 37 weeks' gestation) compared with placebo or no intervention (low certainty).
Vitamin D supplementation probably leads to lower low birthweight (less than 2500 g) compared with placebo or no intervention (moderate certainty).
Any intermittent iron regimen (with or without other vitamins and… showed no clear difference in low birthweight (less than 2500 g) compared with daily regimen (with same vitamins and minerals)‐infant outcomes (low certainty).
It is very uncertain whether any intermittent iron regimen (with or without other vitamins and… changes side effects (any reported throughout intervention period) compared with daily regimen (with same vitamins and minerals)‐maternal outcomes (very low certainty).
Any intermittent iron regimen (with or without other vitamins and… led to lower maternal clinical malaria or other infection in pregnancy compared with daily regimen (with same vitamins and minerals)‐maternal outcomes; GRADE not reported.
Any intermittent iron regimen (with or without other vitamins and… showed no clear difference in birthweight (g) compared with daily regimen (with same vitamins and minerals)‐infant outcomes (low certainty).
Any intermittent iron regimen (with or without other vitamins and… showed no clear difference in premature birth (less than 37 weeks of gestation) compared with daily regimen (with same vitamins and minerals)‐infant outcomes (low certainty).
It is very uncertain whether any intermittent iron regimen (with or without other vitamins and… changes neonatal death (within 28 days after delivery) compared with daily regimen (with same vitamins and minerals)‐infant outcomes (very low certainty).
It is very uncertain whether any intermittent iron regimen (with or without other vitamins and… changes maternal anaemia at term (Hb less than 110 g/L at 37 weeks'… compared with daily regimen (with same vitamins and minerals)‐maternal outcomes (very low certainty).