Eleven RCTs (1,571 participants) were included in the review. Sample sizes ranged from 27 to 377. Final follow-up ranged from one to six months after delivery. Diagnostic interviews to confirm postnatal depression were conducted in seven studies. Only two studies reported that the interviewer was blind to the treatment group. Six studies reported use of intention-to-treat analysis but the methods and reporting were often inadequate and only three studies reported a sample size calculation.
Six trials reported on interventions that were significantly more effective in reducing the incidence and/or symptoms of postnatal depression than a control group.
Greater effectiveness was reported for interventions delivered to women with moderate to severe depression (two studies) than interventions delivered to participants with no or low levels of depression (three trials).
Five out of seven trials reported that psychological treatments were effective. One out of four educational interventions were reported to be effective. Most of the effective interventions included a major component addressing interpersonal relationships.