It is very uncertain whether vitamin D + calcium supplementation changes gestational diabetes compared with placebo or no intervention (very low certainty).
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).
A dose of vitamin D 601 IU or higher probably leads to lower gestational diabetes compared with 600 IU or lower alone or with other nutrients (moderate certainty).
A dose of vitamin D 601 IU or higher showed no clear difference in preterm birth compared with 600 IU or lower alone or with other nutrients (low certainty).
It is very uncertain whether A dose of vitamin D 601 IU or higher changes low birthweight compared with 600 IU or lower alone or with other nutrients (very low certainty).
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).
A dose of vitamin D 4000 IU/d or more showed no clear difference in gestational diabetes compared with 3999 IU/d or less alone or with any other nutrient (low certainty).
A dose of vitamin D 4000 IU/d or more showed no clear difference in preterm birth compared with 3999 IU/d or less alone or with any other nutrient (low certainty).
A dose of vitamin D 4000 IU/d or more showed no clear difference in low birthweight compared with 3999 IU/d or less alone or with any other nutrient (low certainty).
Vitamin A supplementation (200,000 to 400,000 IU) showed no clear difference in maternal mortality compared with placebo or no treatment (moderate certainty).
Vitamin A supplementation (200,000 to 400,000 IU) showed no clear difference in maternal adverse effects after administration: abdominal pain compared with placebo or no treatment (low certainty).
Vitamin A supplementation (200,000 to 400,000 IU) showed no clear difference in infant mortality compared with placebo or no treatment (low certainty).
It is very uncertain whether vitamin A supplementation (200,000 to 400,000 IU) changes infant morbidity (gastroenteritis) compared with placebo or no treatment (very low certainty).
Vitamin A supplementation (200,000 to 400,000 IU) showed no clear difference in infant adverse effects: bulging fontanelle compared with placebo or no treatment (low certainty).
The intervention showed no clear difference in stillbirth (moderate certainty).
The intervention showed no clear difference in intrauterine growth restriction (high certainty).
The intervention showed no clear difference in preterm birth (< 37 weeks' gestation) (high certainty).
The intervention showed no clear difference in preterm prelabour rupture of membranes (low certainty).