During development, the fetus is entirely dependent on the mother for its nutrient requirements. Subsequently, 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 applies mainly to micronutrients. Even now, iron deficiency is a common disorder, especially in pregnancy. Similarly, copper intake in the U.K. population is rarely above adequate levels. It is now becoming clear that nutrient deficiencies during pregnancy can result in problems for the offspring, in both the short- and long-term. Early studies showed that lambs born to mothers on copper-deficient pastures developed 'swayback', with neurological and muscular symptoms that could not be reversed by postnatal supplementation. Our own findings have shown that prenatal iron deficiency results in increased postnatal blood pressure, even though the offspring have normal dietary iron levels from birth. These observations emphasize the importance of iron and copper in growth and development. Complicating the situation further is the fact that copper and iron are known to interact with each other in many ways, including absorption and intracellular transport. However, their interactions during the pregnancy appear to be more complex than during the non-pregnant state. In the present review, we examine the importance of these metals and their interactions, the consequences, both short- and long-term, of deficiency and consider some possible mechanisms whereby these effects may be generated.