In the past 20 years, there has been increasing recognition that for some women, pregnancy may be burdened with mood problems, in particular depression, that may impact both mother and child. With identification of risk factors for postpartum depression and a growing knowledge about a biologic vulnerability for mood change following delivery, research has accumulated on attempts to prevent postpartum depression using various psychosocial, psychopharmacologic, and hormonal strategies. The majority of psychosocial and hormonal strategies have shown little effect on postpartum depression. Notwithstanding, results from preliminary trials of interpersonal therapy, cognitive-behavioural therapy, and antidepressants indicate that these strategies may be of benefit. Information on prevention of postpartum depression using dietary supplements is sparse and the available evidence is inconclusive. Although a few studies show promising results, more rigorous trials are required. The abounding negative evidence in the literature indicates that postpartum depression cannot be easily prevented, yet.