LAUSR

Anonymized data were obtained from the Human Fertilization and Embryology Authority to determine whether gestational surrogacy influences perinatal outcomes compared with pregnancies after autologous IVF. A total of 103,160 singleton live births, including 244 after gestational surrogacy, 87,571 after autologous fresh IVF and intractyoplasmic sperm injection (ICSI) and 15,345 after autologous frozen embryo transfers were analysed. Perinatal outcomes of pretern birth (PTB), low birth weight (LBW) and high birth weight (HBW) were compared. No difference was found in the risk of PTB and LBW after gestational surrogacy compared with autologous fresh IVF-ICSI: PTB (adjusted OR 0.90, 95% CI 0.56 to 1.42), LBW (adjusted OR 0.90, 95% CI 0.57 to 1.43) and gestational surrogacy compared with autologous frozen embryo transfers: PTB (adjusted OR 0.96, 95% CI 0.58 to 1.60), LBW (adjusted OR 1.16, 95% CI 0.69 to 1.96). The incidence of HBW was significantly higher after gestational surrogacy compared with fresh IVF-ICSI (adjusted OR 1.94, 95% CI 1.38 to 2.75); no difference was found in HBW between gestational surrogacy and autologous frozen embryo transfers. The dataset is limited by lack of information on confounders, i.e. ethnicity, body mass index, underlying medical history, which could result in residual confounding.