The biological pathways leading to depression at any time in life, including around pregnancy, are still poorly characterized. Oxytocin, a hormone involved in delivery and lactation, has received recent attention regarding its additional role in maternal emotions and care taking behaviors after birth. Specifically, lower plasma oxytocin concentration in the third trimester of pregnancy has been linked to an increased risk of depression at two weeks postpartum (Skrundz et al., 2001).