Seven pregnancies complicated by partial placenta membranacea occurring over a 2-year period are described. The condition is encountered more frequently than the total or near-total form, but is similarly associated with recurrent antepartum haemorrhage, miscarriage or preterm delivery. Diagnosis by ultrasound scan may prove difficult. Five pregnancies had histological evidence of chorioamnionitis, which may have helped to precipitate labour; three fetuses showed pulmonary inflammatory changes of at least 2 days' duration. No maternal predisposing factors could be elicited.