Current interest in preventive nutritional supplementation strategies during the reproductive cycle in developed countries focuses mainly on iron and folic acid. Iron deficiency is the most common cause of anaemia. Inadequate iron nutrition is mainly a problem in developing countries but it also seems to affect a large proportion of pregnant women in the industrialised world. There is no chance for diet modification alone to meet iron requirements during pregnancy. However, dietary advice must be provided to increase iron intake and iron bioavailability. The best choice is prescribed supplementation adapted to the individual's needs. Folic acid supplementation during the periconceptional period reduces the occurrence and recurrence of neural tube defects (NTDs). According to the updated edition of American Dietary Reference Intakes, recommended dietary allowance for folate for women of childbearing age varies throughout the reproductive cycle from 400 microg day(-1) of dietary folate equivalents (DFEs) for non-pregnant women, to 600 microg day(-1) DFEs for pregnant women and 500 microg day(-1) DFEs in lactating women. Increasing dietary folate, fortifying staple foods with folic acid or use of folic acid supplements can increase folate intake.