Postpartum depression is a combination of physical, emotional, and behavioral changes that occur after childbirth. The rapid drop in estrogen and progesterone levels, as well as the social and psychological changes resulting from the birth of a child, can often trigger depression in women. Common symptoms include crying, irritability, fatigue, loss of appetite, and feelings of guilt and anxiety. Women who develop postpartum depression often feel unable to care for their baby or themselves. Postpartum depression is common; it is estimated that about 10 percent of new mothers experience some symptoms of depression following delivery. Risk factors include a personal or family history of depression and a history of suffering from premenstrual dysphoric disorder (PMDD), a severe form of premenstrual syndrome (PMS). The purpose of this study is to evaluate the effectiveness of calcium supplements taken during pregnancy in reducing the likelihood of postpartum depression in women at risk for developing this condition.