Effect of gonadotrophin priming on in-vitro maturation of oocytes collected from women at risk of OHSS

This study examined the effects of human menopausal gonadotrophin (HMG) or human chorionic gonadotrophin (HCG) priming on cumulus–oocyte complex (COC) morphology, oocyte maturation and embryo development in patients undergoing in-vitro maturation (IVM) cycles. The patients were primed with nothing (group 1), low-dose HMG (group 2) or 10,000 IU HCG (group 3) before oocyte retrieval. COC with dispersed cumulus cell appearance was only observed in group 3. In addition, 11% of metaphase II stage oocytes at the time of retrieval were collected from group 3. Oocyte maturation in vitro in group 3 was faster than that in groups 1 and 2. The blastocyst development rate of residual embryos after embryo transfer in group 3 was significantly higher than that of groups 1 and 2 (P < 0.05). These results suggest that HCG priming may stimulate the COC, promote oocyte maturation, and improve developmental competence in IVM cycles.