Effects of human menopausal gonadotropin on zona pellucida and pregnancy outcomes of ovarian stimulation protocols

BACKGROUND Human menopausal gonadotropin (hMG) has contributed many improvements to human assisted reproduction. However, effects of hMG on oocyte development and clinical results remain controversial. OBJECTIVE This study was conducted to investigate the effects of hMG on the zona pellucida of oocytes, as well as clinical results in superovulation treatment. MATERIALS AND METHODS This retrospective study was performed with 150 cycles of long-protocol treatment using recombinant follicle-stimulating hormone (r-FSH) with or without hMG. The number of retrieved oocytes, fertilization rate, implantation rate, pregnancy rate, and birefringence and thickness of the zona pellucida of oocytes were investigated. RESULTS No significant differences were existed in r-FSH +hMG, and r-FSH groups in the number of retrieved oocytes (11.99±0.75 vs. 13.9±0.73, p=0.06), maturation rate (84.76% vs. 83.32%, p=0.42), pregnancy rate (37.31% vs. 37.66%, p=0.96), and embryo implantation rate (28.97% vs. 23.26%, p=0.30). However, fertilization rate (82.95% vs. 78.75%; p=0.02) was different. Zona pellucida birefringence was lower in the r-FSH +hMG group than in the r-FSH group (6.70±0.50 vs. 7.04±0.31; p=0.53). Thickness values of the metaphase-II zona pellucida of the r-FSH +hMG group on the first (19.20±0.14 vs. 18.75±0.10; p=0.01) and second (18.69±0.12 vs. 18.17±0.14; p=0.00) days of insemination were both higher than those of the r-FSH group. CONCLUSION hMG positively influenced the improvement of oocyte fertilization, as well as the birefringence and thickness of zona pellucida.