Risk factors for clinical pregnancy loss after IVF in women with PCOS.

RESEARCH QUESTION:Which factors are associated with the risk of clinical pregnancy loss in women with polycystic ovary syndrome (PCOS) undergoing IVF? DESIGN:Case-control study nested in a multicentre randomized trial comparing live birth rates between fresh and frozen embryo transfer in women with PCOS. Women with the outcome of clinical pregnancy loss were selected as the case group, those with live birth as the control group. Parameters before IVF treatment and variables during ovarian stimulation and embryo transfer were compared. RESULTS:Women with clinical pregnancy loss had higher maternal body mass index (BMI, P = 0.010), anti-Müllerian hormone (AMH, P = 0.032), 2-h glucose concentration after 75 g oral glucose tolerance test (OGTT, P = 0.025), and a higher proportion of fresh embryo transfers (P = 0.001). There were significant interactions between the types of transfer and antral follicle count (AFC, P = 0.013), 2-h glucose concentration after OGTT (P = 0.024) on clinical pregnancy loss in PCOS, indicating that these factors may have different effects on pregnancy loss after fresh versus frozen embryo transfer. When the multivariable logistic regression analysis was stratified by the fresh or frozen embryo transfer, AFC (adjusted odds ratio [aOR] 1.03, 95% confidence interval [CI] 1.01-1.05) was a risk factor for clinical pregnancy loss after fresh embryo transfer, while 2-hour glucose concentration after OGTT (aOR 1.13, 95% CI 1.01-1.25) was associated with clinical pregnancy loss in frozen embryo transfer (FET) cycles. CONCLUSIONS:In women with PCOS, fresh embryo transfer, higher BMI, AFC and 2-h glucose concentration after OGTT were risk factors for clinical pregnancy loss. FET may be a better choice to decrease the risk of clinical pregnancy loss, especially for those with higher AFC. During FET, 2-h glucose after OGTT appears to be associated with clinical pregnancy loss and warrants close monitoring.