Objective: The severity of postpartum psychosis calls for further research on the association between obstetric variables and this psychiatric disorder.
Method: A total of 1 133 368 Swedish first-time mothers were included during a 29-year period yielding 1413 hospitalized cases of postpartum psychosis. Several obstetric variables were analysed separately after adjustment for possible confounders.
Results: Respiratory disorder in the neonate, severe birth asphyxia, preterm birth, caesarean section, perinatal death and SGA infant were associated with an increased risk of postpartum psychosis. After adjustment for previous hospitalization for psychiatric disorder only preterm birth and acute caesarean section remained significant risk factors for postpartum psychosis (relative risks were 1.20 and 1.31 respectively). The relative risk of postpartum psychosis among first-time mothers with previous hospitalization for psychiatric disorder was increased more than 100-fold.
Conclusion: Careful clinical risk assessments of postpartum psychosis are crucial among women with a history of psychiatric disorder whereas obstetric variables have a minor importance.