Association between fetal growth restriction and stillbirth in twin compared with singleton pregnancies

ABSTRACT Objectives Twin pregnancies are at higher risk of stillbirth compared to singletons. Fetal growth restriction (FGR) is a major cause of perinatal mortality, but its impact on twins vs singletons remains unclear. The primary objective of this study was to investigate the association of FGR and small‐for‐gestational age (SGA) with stillbirth in twin compared with singleton pregnancies. A secondary objective was to assess these associations stratified by gestational age at delivery. Furthermore, we aimed to compare the associations of FGR and SGA with stillbirth in twin pregnancies using twin‐specific vs singleton birth‐weight charts, stratified by chorionicity. Methods This was a retrospective cross‐sectional study of pregnancies receiving obstetric care and giving birth between 1999 and 2022 at St George's Hospital, London, UK. The exclusion criteria included triplet and higher‐order pregnancies, those resulting in miscarriage or live birth at ≤ 23 + 6 weeks, termination of pregnancy and missing data regarding birth weight or gestational age at birth. Birth‐weight data were collected and FGR and SGA were defined as birth weight