Objective To explore the relation between pre-operative psychiatric morbidity, menstrual blood loss and psychiatric outcome in women receiving endometrial ablation for heavy periods.

Design A prospective cohort study.

Setting The menorrhagia clinic at Leeds General Infirmary.

Population One hundred and twenty consecutive women referred to the Clinic for endometrial ablation.

Methods Psychiatric interview and actual menstrual blood loss measurements at presentation pre-operatively and one year post endometrial ablation.

Main outcome measure Psychiatric status using the semi-structured interview, Present State Examination, with measurement of menstrual blood loss.

Results Endometrial ablation was performed on 92 women. Of the 87 women evaluated 51 (59%) had clinically significant psychiatric symptoms, mainly depression and anxiety. Psychiatric morbidity fell to 21.8% at one year after endometrial ablation. Women with the best psychiatric outcome (6% post-operative psychiatric morbidity) were those with genuine menorrhagia (≥80 mL) and low psychiatric morbidity pre-operatively. Those who fared worst (39% post-operative psychiatric morbidity) were women with high pre-operative psychiatric morbidity and low menstrual blood loss. Of seven women with very low losses [mean 19 mL (SD 17)] who did not proceed to surgery after counselling, six (86%) had significant psychiatric morbidity.

Conclusions Pre-operative psychiatric status and menstrual blood loss are predictors of outcome of surgery for women with reported heavy periods.