Study design and data collection
We retrospectively reviewed all cases of singleton antepartum stillbirths and live births which were delivered at our tertiary referral centre between January 2003 and December 2019. IUFD cases, which fulfilled the study’s inclusion and exclusion criteria, were matched with singleton live births for maternal age, gravidity, parity, gestational age at delivery and fetal sex (Appendix S1 ). Inclusion criteria for antepartum stillbirths were singleton IUFDs above 21+0 gestational weeks with documented fetal and maternal characteristics either at antenatal booking or at time of delivery. Exclusion criteria for IUFDs were multiple pregnancies, medical or surgical terminations of pregnancies, perinatal fetal deaths and cases with missing fetal and maternal demographics and medical history. Causes of death in IUFDs was defined as the “initial, demonstrable pathophysiological entity initiating the chain of events that has irreversibly led to death” in recognition of potentially multiple competing risks and events and was categorized according to theCauses of death and associated conditions (CODAC) classification.8