Objective: This paper reports the findings of a prospective longitudinal study of 272 nulliparous pregnant women, which investigated as one of its objectives the psychological sequelae of obstetric procedures. Method: Participants completed structured interviews and standardised, published psychometric questionnaires, including the Rosenberg Self-Esteem Scale and the Profile of Mood States late in pregnancy and again early in the postpartum period. Results: Little evidence was found to support the notion that the total number of obstetric interventions was linked to a deterioration in postpartum mood. Significant adverse psychological effects were associated with the mode of delivery. Those women who had spontaneous vaginal deliveries were most likely to experience a marked improvement in mood and an elevation in self-esteem across the late pregnancy to early postpartum interval. In contrast, women who had Caesarean deliveries were significantly more likely to experience a deterioration in mood and a diminution in self-esteem. The group who experienced instrumental intervention in vaginal deliveries fell midway between the other two groups, reporting neither an improvement nor a deterioration in mood and self-esteem. Conclusions: The findings of this study suggest that operative intervention in first childbirth carries significant psychological risks rendering those who experience these procedures vulnerable to a grief reaction or to posttraumatic distress and depression.