Fresh versus frozen embryo transfer in women with polycystic ovaries syndrome undergoing in vitro fertilisation

Background Polycystic ovarian syndrome (PCOS) cases undergoing in vitro fertilisation (IVF) are widely at risk of ovarian hyperstimulation; therefore, elective freezing of all embryos to be transferred in a later cycle is preferred. We aimed to compare the pregnancy outcome between the fresh and the frozen embryo transfer (ET) in PCOS cases undergoing IVF with antagonist ovarian induction using human chorionic gonadotropin (HCG) as a trigger. Methods In this prospective randomised study, 110 infertile PCOS women underwent fresh ET (group A) or frozen ET (group B) with GnRH-antagonist protocol. The primary outcome was the chemical and clinical pregnancy rates. The secondary outcomes were the ongoing pregnancy rate, ovarian hyperstimulation syndrome (OHSS) rate, pregnancy loss rate, ectopic pregnancy rate, and congenital anomalies rate. Results There was no significant difference between both groups regarding chemical pregnancy rate (44.23% vs 47.27%, P = 0.752), clinical pregnancy rate (42.31% vs 43.64%, P = 0.89), ongoing pregnancy rate (38.46% vs 41.82%, P = 0.723), pregnancy loss rate (17.39% vs 15.4%, P = 1), ectopic pregnancy rate (1.92% vs 0%, P = 0.486) and anomaly malformation rate (4.35% vs 3.85%, P = 1). On the other hand, the incidence of OHSS was significantly less in group B than in group A (3.64% vs 19.23%, P = 0.011), and the OHSS grade was less severe in group B than in group A ( P = 0.033). However, there was no statistically significant difference between both regarding the need for hospitalisation ( P = 0.111), ICU admission ( P = 0.486), and ascites tapping ( P = 0.486). Conclusions Under GnRH-antagonist protocol, frozen ET has the upper hand in PCOS undergoing IVF treatment for infertility, as it protects against OHSS and decreases its severity. Trial registration It was first registered at ClinicalTrials.gov on 22/12/2021 with registration number NCT05167838.