The supply of iron, folic acid, and vitamin D is important for the health and well-being of pregnant women and their children. However, many open questions and controversial discussions exist among scientific bodies worldwide with respect to the adequate supply of these micronutrients during the critical pre- and postnatal periods of life and the possible need for supplementation over and above typical dietary intakes. In the publication at hand, the current knowledge and unresolved questions on the supply of vitamin D, folic acid, and iron for pregnant women, lactating women, and infants, and their health effects are discussed. In particular, the question is addressed of whether, and under which circumstances, supplementation with these micronutrients in addition to usual dietary intakes is advisable. The topics presented will be of great interest for the scientific community in general as well as for those involved in public health policy issues.