Outcome measures
Data on pregnancy outcome were obtained from the maternity hospital records or the general practitioners of women. Stillbirths were divided into those that occurred prenatally and those that occurred during labour (intrapartum stillbirths). Antepartum stillbirths were divided into those that were associated with placental dysfunction (preeclampsia or birthweight <10th percentile) and those due to other causes. Antepartum stillbirths were further divided based on gestational age at stillbirth into those that occurred at any gestational age, at <37 weeks and at <32 weeks.