Moderate-to-severe ovarian hyperstimulation syndrome: A retrospective multivariate logistic regression analysis in Chinese patients.

Background. Ovarian hyperstimulation syndrome (OHSS), a life-threatening complication occurring in stimulated ovarian cycles, arises from treatment with gonadotropin for inducing follicular maturation. Objectives. The aim of this study was to compare the risk factors between patients with severe OHSS and those without OHSS after in vitro fertilization by intracytoplasmatic sperm injection/embryo transfer (IVF-ICSI/ET). Identifying the associated risk factors may provide guidance for clinicians on how to prevent OHSS. Material and methods. The retrospective study involved patients who had completed IVF-ICSI/ET cycles. The difference in markers for predicting the occurrence of OHSS between groups was compared. The potential protective and risk factors, as well as the predictive markers, were identified. Results. Patients with OHSS were younger (p = 0.015), had higher basal antral follicle counts (AFC) (p < 0.001) and lower total dosages of gonadotropin (Gn) (p = 0.011). On the day of human chorionic gonadotropin (hCG) administration, significantly higher total numbers of follicles (p < 0.001), serum estradiol (E2) (p < 0.001) and progestrone (Pg) (p = 0.001) levels, numbers of oocytes (p < 0.001) and metaphase II (MII) oocytes (p < 0.001) were also observed in the OHSS group when compared to the non-OHSS group. A univariate regression analysis revealed that age (OR = 0.898, 95% CI =0.822-0.981) and total dosage of Gn (OR = 0.999, 95% CI = 0.999-1.000) were protective factors, whereas AFC (OR = 1.090, 95% CI = 1.051-1.131) and, on the day of hCG injection, the number of follicles (OR = 1.185, 95% CI = 1.027-1.230), serum E2 (OR = 1.000, 95% CI = 1.000-1.000) and Pg (OR = 2.773, 95% CI = 0.510-3.370) levels, the number of oocytes (OR = 1.254, 95% CI = 0.894-1.472) and MII oocytes (OR = 1.238, 95% CI = 0.747-1.217) were risk factors for OHSS. However, a multivariate regression analysis showed that the total number of follicles (OR = 1.124, 95% CI = 1.027-1.230) was the only predictive factor for the occurrence of OHSS. Conclusions. The study demonstrated that the follicle count measured on the day of hCG administration was the only predictive factor forthe occurrence of OHSS. This provides basic guidance to clinicians on the prevention of the complication when using assisted reproductive technologies (ART).