Anemia affects 36% of pregnant women worldwide. Of those affected, around 40% is due to iron deficiency (ID).

Iron is an essential micronutrient involved in vital processes such as erythropoiesis, immune responses, and importantly—during pregnancy—placental and fetal development.

Although menstrual bleeding can impact the incidence of ID even before the onset of pregnancy, this narrative review is pregnancy focused and will explore the impact of ID on placental development and iron uptake, fetal development and immunity, and maternal and infant susceptibility to infection.

Although there have been advances in this area of research, much is needed to understand the regulation of iron and the effects of ID during pregnancy.

Notably, more human studies are essential to generate the best evidence to advance strategies to reduce the incidence of ID during pregnancy to improve maternal, neonatal, and infant health.