Risk of preeclampsia in artificial cycles of frozen embryo transfer in vitro fertilization pregnancies

Zhang et al1 investigated the importance of corpus luteum and relaxin in preventing hypertensive disorders of pregnancy (HDP), including preeclampsia, in women with polycystic ovarian syndrome who were undergoing artificial frozen embryo transfer (FET) cycles when compared to letrozole ovulation induction cycles. They also discussed perturbed vascular remodeling caused by prematurely elevated estrogen levels and impaired angiogenesis as potential culprits to the increased risk of HDP in women undergoing FET cycles.