High Serum FSH is Associated with Brown Oocyte Formation and a Lower Pregnacy Rate in Human IVF Parctice

Abstract

Background/Aims: To investigate whether brown zona pellucida (ZP) of oocytes affects the outcome of fertilization, embryo quality and pregnancy rate in in vitro fertilization-embryo transfer (IVF-ET). Methods: Based on the ZP color of their oocytes, a total number of 703 patients dated from 2012 to 2014 were divided into a normal egg group (group A) and a brown oocyte group (group B), with 629 and 74 cases, respectively. Clinical characteristics, gonadotropin (Gn) days, Gn dosage, serum hormone levels on the day of human chorionic gonadotropin (HCG) injection, ZP thickness (ZPT) of the eggs, fertilization rate, rescue intracytoplasmic sperm injection (rICSI) rate, good-quality embryo rate and pregnancy rate were compared between the two groups. Results: No significant differences were found in the duration and the causes of infertility, and their basal level of endocrine hormone before IVF-ET between normal egg group and brown egg group. The level of serum hormone including estradiol, progesterone and luteinizing hormone on the day of HCG injection were again similar. Moreover, there were no differences in number of mature oocytes, oocyte fertilization rates and rICSI rates after IVF between the two groups. However, we observed that the ZPT of brown oocytes (group B) was higher than that of normal oocytes (group A). Moreover, the Gn dosage and FSH levels on the day of HCG injection were significantly higher in group B than in group A and the good-quality embryo rate and pregnancy rate in group B were lower than those in group A. Conclusion: Compared with normal eggs, oocytes with a brown ZP were found to have a higher ZPT, lower embryo quality and lower pregnancy rate, which might be due to a high Gn dosage injection and high serum FSH levels during IVT-ET cycles.