Objective To identify the impact of pregnancy and childbirth, and severe obstetric morbidity on outcome 6 to 12 months postpartum. Design Questionnaire assessment of postnatal outcome in a cohort study. Setting South East Thames, UK. Population All women resident in South East Thames and delivering between 1st March 1997 and 28th February 1998. Methods Questionnaire study of a cohort of women who experienced a severe obstetric morbidity during pregnancy or labour (cases), compared with a cohort of women who did not (controls). Main outcome measures Assessment of postnatal depression risk [Edinburgh Postnatal Depression Scale (EPDS)], general health [Short Form 36 (SF-36)], sexual activity and use of health services between 6 and 12 months postpartum. Results There were 331 cases and 1339 controls out of 48,262 deliveries. Six to 12 months after delivery, 77 (23.3%) of cases and 272 (20.5%) of the controls were at risk of postnatal depression ( P = 0.25; 95% CI for difference −2.2% to 7.9%), 43.1% of cases were having problems with sexual relations compared with 18.7% of controls ( P < 0.001; 95% CI for difference 8.9% to 21.9%). There was evidence of poorer general health in cases. Some 31.5% of cases attended outpatients in the first six months and 9.4% required emergency admission to hospital compared with 17.0% ( P < 0.001; 95% CI for difference 9.1% to 19.9%) and 3.7% ( P < 0.001; 95% CI for difference 2.4% to 9.0%), respectively, in controls. Conclusion Both control pregnancy and childbirth and severe obstetric morbidity are associated with significant postnatal morbidity. A severe obstetric morbid event significantly influences women's sexual health and wellbeing and increases health services utilisation. Prevention and appropriate management of severe obstetric morbid events may reduce these outcomes.