Pregnancy is a period of rapid growth and cell differentiation for both the mother and fetus. Consequently, it is a period when both are vulnerable to changes in dietary supply, especially of those nutrients that are marginal under normal circumstances. In developed countries this vulnerability applies mainly to micronutrients. Even now, Fe deficiency is a common disorder, especially in pregnancy. Similarly, Cu intake in the UK population is rarely above adequate levels, which is a matter of some concern, both in terms of public health and possible clinical consequences. In early studies it was shown that lambs born to mothers on Cu-deficient pastures develop ‘swayback,’ with neurological and muscular symptoms that cannot be reversed by postnatal supplementation. More recently, rat studies have shown that responses such as the ‘startle’ response are lost in offspring of Cu-deficient mothers. Data have shown that prenatal Fe deficiency results in increased postnatal blood pressure, even though the offspring have normal dietary Fe levels from birth. These observations emphasise the importance of Fe and Cu in growth and development. In the present review the importance of these metals and the consequences, both short term and long term, of deficiency will be discussed and some possible mechanisms whereby these effects may be generated will be considered.