Role of micronutrients in the periconceptional period

Micronutrient deficiencies have been associated with significantly high reproductive risks, ranging from infertility to fetal structural defects and long-term diseases. In this review we focus on the reproductive risks related to some micronutrients during the periconceptional period, a critical step in determining fetal development and health due to the potential onset of several disorders. Embase Medline and PubMed databases, Google-indexed scientific literature and periodics from on-line University of Milan Bibliotecary Service were searched to identify relevant publications. In vivo human studies were mainly searched for, but when needed animal studies as well as in vitro and cell culture experiments were also considered. Fertility, conception, implantation, fetal organogenesis and placentation are the critical stages potentially affected by nutrition during the periconceptional period. Reactive oxygen species (ROS) and total homocysteine (tHcy) plasma levels are factors involved in the respective mechanisms. The preconceptional period is particularly important since it affects both fertility and the early stages of gestation. Micronutrients' dietary intake and maternal status affect the different phases of the onset and development of pregnancy as well as of the conceptus. Although human studies are scarce, and conclusive evidence is provided solely for periconceptional folate and prevention of neural tube defects (NTDs), the overall data indicate that micronutrients may affects fertility, embryogenesis and placentation, and the prophylactic use of some micronutrients may be useful in preventing several adverse pregnancy outcomes. Efforts to increase awareness of a healthy diet should be strengthened not only throughout pregnancy but also before. However, further researches in humans are necessary to optimise periconceptional micronutrient requirements.