The placenta and its myriad functions are central to successful reproductive outcomes. These functions can be influenced by the environment encountered throughout pregnancy. Such influences can alter the appropriate genetic programming needed to allow for sustained pregnancy and appropriate fetal development. This altered programming may result from epigenetic alterations related to environmental exposures. Epigenetic alterations are now being linked to several important reproductive outcomes, including early pregnancy loss, intrauterine growth restriction, congenital syndromes (eg. Beckwith-Weidemann syndrome), preterm birth and preeclampsia. The diversity of environmental exposures linked to adverse reproductive effects continues to grow. Much attention has focused on the role of endocrine disruptors and other xenobiotics in infertility, but recent work is demonstrating that these chemicals may have adverse effects in pregnancy and development as well. Environmental oxygen is also critical in early pregnancy success. There are clear links between altered oxygen levels and placentation amongst other effects. As research continues to increase our understanding of the molecular processes including epigenetic regulation that influence pregnancy, it will be critical to specifically examine how the environment, broadly defined, may play a role at altering these critical functions.