OBJECTIVE:To assess the effectiveness of a midwife led debriefing session during the postpartum hospital stay in reducing the prevalence of maternal depression at six months postpartum among women giving birth by caesarean section, forceps, or vacuum extraction. DESIGN:Randomised controlled trial. SETTING:Large maternity teaching hospital in Melbourne, Australia. PARTICIPANTS:1041 women who had given birth by caesarean section (n= 624) or with the use of forceps (n= 353) or vacuum extraction (n= 64). MAIN OUTCOME MEASURES:Maternal depression (score >/=13 on the Edinburgh postnatal depression scale) and overall health status (comparison of mean scores on SF-36 subscales) measured by postal questionnaire at six months postpartum. RESULTS:917 (88%) of the women recruited responded to the outcome questionnaire. More women allocated to debriefing scored as depressed six months after birth than women allocated to usual postpartum care (81 (17%) v 65 (14%)), although this difference was not significant (odds ratio=1.24, 95% confidence interval 0.87 to 1.77). They were also more likely to report that depression had been a problem for them since the birth, but the difference was not significant (123 (28%) v 94 (22%); odds ratio=1. 37, 1.00 to 1.86). Women allocated to debriefing had poorer health status on seven of the eight SF-36 subscales, although the difference was significant only for role functioning (emotional): mean scores 73.32 v 78.98, t= -2.31, 95% confidence interval -10.48 to -0.84). CONCLUSIONS:Midwife led debriefing after operative birth is ineffective in reducing maternal morbidity at six months postpartum. The possibility that debriefing contributed to emotional health problems for some women cannot be excluded.