During pregnancy, iron is transported from mother to fetus across the placenta. Iron is essential for many biological processes, including the transfer of oxygen in blood, but it can also be toxic. Elaborate and elegant mechanisms have evolved to make sure that the potential for oxidative damage is minimized. In this article, we examine how iron is transferred from the maternal liver to the placenta, taken up, and transferred to the fetal liver. We consider the molecular mechanisms and how they are regulated. In addition, we use data from previously published articles to examine how the processes are regulated and what adaptations can occur to ameliorate the consequences of iron deficiency--an all too common problem in pregnancy, even in the developed world. Finally, we examine some of the many questions that remain about the transfer process and consider how nutrients interact and what the consequences of these interactions may be for the mother and her developing infant.