Taking a multivitamin with many different nutrients during pregnancy in developing countries may help prevent babies from being born too small or underweight, compared to just taking iron supplements.

Giving pregnant women lipid-based nutrient supplements instead of standard vitamin pills is linked to a lower chance of having a baby born too small.

Giving pregnant women in developing countries a balanced supplement with extra energy and protein helps their babies be born heavier and lowers the chance of the baby being born too small.

Giving pregnant women in lower-income countries extra protein and calorie supplements might cut the chance of babies being born dead by about 60%. While the results look promising, researchers note that more high-quality studies are needed to be completely sure.

Giving pregnant women in low-income areas a daily balanced energy and protein supplement, instead of just iron and folic acid, helps their babies be born about 50 grams heavier. This small but important weight gain can help prevent babies from being too small at birth.

Giving pregnant women in developing countries extra protein and energy supplements doesn't seem to change how often babies are born too early or die shortly after birth. While it might help the baby grow better and prevent stillbirths, it doesn't change when the baby is born or save newborns from dying.