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.