Fetal long-chain polyunsaturated fatty acid (LC-PUFA) supply during pregnancy is of major importance, particularly with respect to docosahexaenoic acid (DHA) that is an important component of the nervous system cell membranes. Growing evidence points to direct effects of DHA status on visual and cognitive outcomes in the offspring. Furthermore, DHA supply in pregnancy reduces the risk of preterm delivery.

Because of limited fetal capacity to synthesize LC-PUFA, the fetus depends on LC-PUFA transfer across the placenta. Molecular mechanisms of placental LC-PUFA uptake and transport are not fully understood, but it has been clearly demonstrated that there is a preferential DHA transfer. Thus, the placenta is of pivotal importance for the selective channeling of DHA from maternal diet and body stores to the fetus. Several studies have associated various fatty acid transport and binding proteins (FATP) with the preferential DHA transfer, but also the importance of the different lipolytic enzymes has been shown.

Although the exact mechanisms and the interaction of these factors remains elusive, recent studies have shed more light on the processes involved, and this review summarizes the current understanding of molecular mechanisms of LC-PUFA transport across the placenta and the impact on pregnancy outcome and fetal development.