Folates and the fetus.

Folate metabolism is sometimes deranged in the early weeks of pregnancy at the time of placentation and organogenesis. Maternal folate deficiency may result in general impairment of fetal growth, which is reflected in low birthweight. Such women also have a high incidence of abortion, abruptio placentae and fetal malformation. Megaloblastic anaemia is the commonest and most easily recognised manifestation of folate deficiency.