Aim: This article is a systematic review of the literature to establish whether there is an advantage in the use of GnRH antagonists (Ant) compared to the long agonist protocol (Ago) in patients with polycystic ovarian syndrome (PCOS).
Material and methods: The meta-analysis was conducted using the MIX software with Mantel?Haenszel weighting method and the fixed effect model.
Results: Five studies were identified. We analyzed 269 Ant and 303 Ago cycles. Pregnancy rates and the incidence of ovarian hyperstimulation syndrome (OHSS) were analyzed in all five studies, abortion rates were analyzed on three. Pregnancy rates did not differ between the groups: 137/269 (Ant Group) versus 172/303 (Ago Group) (OR: 0.80 CI: [0.57-1.11]). The incidence of OHSS per Ant (13/269) was significantly lower compared to the Ago (35/303) (OR: 0.47 CI: [0.24-0.92]). No difference was found between the two groups in the abortion rate: 10/77 (Ant Group) versus 9/88 (Ago Group) (OR: 1.29 CI: [0.49-3.36]).
Conclusion: The limited evidence present in literature suggests that in patients with PCOS there is no difference between a long Ago and an Ant protocol in terms of pregnancy and abortion rates. It seems more likely that the use of the Ant may reduce the incidence of OHSS.