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 C and vitamin E showed no clear difference in any adverse effects of vitamin supplementation sufficient to stop… compared with placebo (moderate certainty).
Vitamin A plus iron plus folate showed no clear difference in total fetal loss (including miscarriages or combined miscarriages… compared with iron plus folate (low certainty).
Vitamin A plus iron plus folate showed no clear difference in early or late miscarriage ‐ Vitamin A + iron + folate versus iron +… compared with iron plus folate (low certainty).
Vitamin A plus iron plus folate showed no clear difference in stillbirth ‐ Vitamin A + iron + folate versus iron + folate compared with iron plus folate (low certainty).
Multivitamin plus iron plus folate showed no clear difference in early or late miscarriage ‐ Multivitamin + iron + folic acid versus… compared with iron plus folate (moderate certainty).
Multivitamin plus iron plus folate leads to lower stillbirth ‐ Multivitamin + iron + folic acid versus iron + folic acid compared with iron plus folate (high certainty).
Multivitamin plus iron plus folate showed no clear difference in total fetal loss (including miscarriages or combined miscarriages… compared with iron plus folate (high certainty).
Any vitamin E supplementation showed no clear difference in stillbirth compared with placebo, no placebo or other supplements (moderate certainty).
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).