Taking iron supplements during pregnancy can lower a mother’s risk of giving birth to a low weight baby, suggests a new study published in the British Medical Journal (BMJ).

Low iron is one of the main causes of anemia during pregnancy, which has been shown to raise the risk of giving birth to a low weight baby. According to another study, from the University of Rochester Medical Center, iron deficiency may also have a profound and long-lasting effect on the brain development of the child.

The researchers of the BMJ study looked at over 90 different studies of prenatal iron use and prenatal anemia involving more than two million women, and found that iron supplements significantly lowered a woman’s risk of developing anemia, and increased her hemoglobin levels. For every 10 mg increase in daily iron intake the risk of anemia went down by 12% and the risk of giving birth to a low-weight baby was reduced by 3%.

Prenatal vitamins are a good way to increase your iron levels and are recommended before and during pregnancy and while breastfeeding.