Does exercise during pregnancy prevent postnatal depression?

OBJECTIVE: To study whether exercise during pregnancy reduces the risk of postnatal depression. DESIGN: Randomized controlled trial. SETTING: Trondheim and Stavanger University Hospitals, Norway. POPULATION AND SAMPLE: Eight hundred and fifty-five pregnant women were randomized to intervention or control groups. METHODS: The intervention was a 12 week exercise program, including aerobic and strengthening exercises, conducted between week 20 and 36 of pregnancy. One weekly group session was led by physiotherapists, and home exercises were encouraged twice a week. Control women received regular antenatal care. MAIN OUTCOME MEASURES: Edinburgh Postnatal Depression Scale (EPDS) completed three months after birth. Scores of 10 or more and 13 or more suggested probable minor and major depression, respectively. RESULTS: Fourteen of 379 (3.7%) women in the intervention group and 17 of 340 (5.0%) in the control group had an EPDS score of ≥10 (p=0.46), and four of 379 (1.2%) women in the intervention group and eight of 340 (2.4%) in the control group had an EPDS score of ≥13 (p=0.25). Among women who did not exercise prior to pregnancy, two of 100 (2.0%) women in the intervention group and nine of 95 (9.5%) in the control group had an EPDS score of ≥10 (p=0.03). CONCLUSIONS: We did not find a lower prevalence of high EPDS scores among women randomized to regular exercise during pregnancy compared with the control group. However, a subgroup of women in the intervention group who did not exercise regularly prior to pregnancy had a reduced risk of postnatal depression.