Any vitamin E supplementation showed no clear difference in preterm birth (less than 37 weeks' gestation) compared with placebo, no placebo or other supplements (high certainty).
Any vitamin E supplementation showed no clear difference in clinical pre‐eclampsia (random‐effects model) compared with placebo, no placebo or other supplements (moderate certainty).
Any vitamin E supplementation showed no clear difference in intrauterine growth restriction (various definitions) compared with placebo, no placebo or other supplements (high certainty).
Any vitamin E supplementation showed no clear difference in prelabour rupture of fetal membranes ‐ preterm compared with placebo, no placebo or other supplements (low certainty).
Any vitamin E supplementation leads to lower bleeding episodes (placental abruption) compared with placebo, no placebo or other supplements (high certainty).
Vitamin A alone showed no clear difference in maternal mortality compared with placebo or no treatment (high certainty).
Vitamin A alone showed no clear difference in perinatal mortality compared with placebo or no treatment (high certainty).
Vitamin A alone probably leads to lower maternal anaemia compared with placebo or no treatment (moderate certainty).
Vitamin A alone may leads to lower maternal clinical infection compared with placebo or no treatment (low certainty).
Vitamin A alone showed no clear difference in preterm birth compared with placebo or no treatment (high certainty).
Vitamin E (topical) led to higher improvement in mucositis compared with vitamin E (swallowed); GRADE not reported.
Vitamin E (topical) led to higher mucositis eradicated compared with vitamin E (swallowed); GRADE not reported.
The review reported a lower odds ratio at maternal prenatal vitamin D ≤50 nmol/L than at ≤35 nmol/L, without a numeric value in the available sources.
The review reported a slightly higher odds ratio at maternal prenatal vitamin D ≤35 nmol/L than at ≤50 nmol/L, without a numeric value in the available sources.
The review reported 44% dental caries prevalence among children of mothers with low prenatal vitamin D.
The review reported an OR of 1.32 when prenatal vitamin D was measured at 6 to 38 gestational weeks.
It is very uncertain whether vitamin D given to lactating mothers changes nutritional rickets ‐ radiological compared with placebo or no treatment (very low certainty).
Vitamin D given to lactating mothers showed no clear difference in adverse effects (hypercalcaemia) compared with placebo or no treatment (low certainty).
Vitamin D given to lactating mothers may leads to lower nutritional rickets ‐ biochemical Alkaline phosphatase, calcium and… compared with placebo or no treatment (low certainty).