Increased risk of maternal and neonatal complications in hormone replacement therapy cycles in frozen embryo transfer

Background The endometrial preparation during frozen embryo transfer (FET) can be performed by natural cycle (NC), hormone replacement therapy (HRT) cycle and cycle with ovulation induction (OI). Whether different FET preparation protocols can affect maternal and neonatal outcomes is still inconclusive. Methods This was a retrospective cohort study that included 6886 women who delivered singleton live birth babies after 28 weeks of pregnancy...