Research studies of biological interventions for the prevention of postpartum depression were eligible for the review. Postpartum depression was defined as inception of depression within the first year after childbirth. To be included, studies had to evaluate an outcome measure of postpartum depression beyond the first postpartum week.
Biological interventions were not defined explicitly, but included studies that evaluated antidepressants, hormones and supplements (calcium and docosahexaenoic acid). Interventions were administered during pregnancy or after birth. Depression was evaluated using a variety of scales.
The author stated neither how the papers were selected for the review nor how many reviewers performed the selection.