Insulin resistance does not affect early embryo development but lowers implantation rate inin vitromaturation-in vitrofertilization-embryo transfer cycle

Although extensive evidence indicates the hyperinsulinemia directly contributes to reproductive dysfunction in polycystic ovarian syndrome (PCOS), influence of insulin resistance (IR) on assisted reproductive technology outcomes is poorly understood. In this study we aimed to evaluate the effects of IR on in vitro maturation-in vitro fertilization-embryo transfer (IVM-IVF-ET) in patients with PCOS.Prospective observational study.Women with PCOS (n = 115) commencing IVM.IR (n = 51) and non-IR (n = 64) women with PCOS ready to commence an IVM cycle were recruited. IR was diagnosed using the glucose tolerance test (GTT) and homeostasis model assessment (HOMA) index. Patients with an abnormal GTT and/or HOMA index >2·4 were considered IR. Patients underwent 115 cycles of unstimulated hCG-primed IVM.Maturation, fertilization, cleavage rates, the number of good-quality embryo, and blastocyst formation rates were not significantly different between groups. However, implantation (11·6% vs 28·7%, P = 0·001, respectively), clinical pregnancy (23·5% vs 53·1%, P = 0·002, respectively), and ongoing pregnancy rates (21·6% vs 46·9%. P = 0·006, respectively) were significantly decreased in the IR group. The negative effect of IR on pregnancy outcomes remained after controlling for age, body mass index (BMI) and lipid profiles (OR 4·928, 95% CI 1·735-13·991, P = 0·003).Pregnancy rate after IVM is impaired in IR patients with PCOS. Oocyte development and embryo quality are not affected, suggesting that the effects of hyperinsulinemia on endometrial function and implantation process underlie the decreased pregnancy rate.