Cohort study of depressed mood during pregnancy and after childbirth.

OBJECTIVE To follow mothers' mood through pregnancy and after childbirth and compare reported symptoms of depression at each stage. DESIGN Longitudinal cohort study. SETTING Avon. PARTICIPANTS Pregnant women resident within Avon with an expected date of delivery between 1 April 1991 and 31 December 1992. MAIN OUTCOME MEASURES Symptom scores from the Edinburgh postnatal depression scale at 18 and 32 weeks of pregnancy and 8 weeks and 8 months postpartum. Proportion of women above a threshold indicating probable depressive disorder. RESULTS Depression scores were higher at 32 weeks of pregnancy than 8 weeks postpartum (difference in means 0.88, 95% confidence interval 0.79 to 0.97). There was no difference in the distribution of total scores or scores for individual items at the four time points. 1222 (13.5%) women scored above threshold for probable depression at 32 weeks of pregnancy, 821 (9.1%) at 8 weeks postpartum, and 147 (1.6%) throughout. More mothers moved above the threshold for depression between 18 weeks and 32 weeks of pregnancy than between 32 weeks of pregnancy and 8 weeks postpartum. CONCLUSIONS Symptoms of depression are not more common or severe after childbirth than during pregnancy. Research and clinical efforts need to be moved towards understanding, recognising, and treating antenatal depression.