The Embryological Characteristics and Clinical Outcomes of Oocytes with Indented Zona Pellucida

Abstract

Purpose The aim of this study is to investigate the embryological characteristics and clinical outcomes of oocytes with indented zona pellucida (ZP). Methods A total of 109 in vitro fertilization (IVF) cycles from 56 subjects had all oocytes with an indented ZP (IZP). Another 1095 cycles of 574 subjects with oocytes retrieved on the same time were included as controls (NZP). The comparisons were conducted between two groups in embryological characteristics and clinical outcomes. Results The patients with IZP suffered from significantly prolonged duration of infertility and were more likely to have primary infertility. In embryonic development, oocytes with IZP demonstrated significantly lower rates of oocyte retrieved, oocyte maturity, normal fertilization, embryo cleavage and embryo utilization. Thirty-two patients with IZP participated in the fresh embryo transfer, with a clinical pregnancy rate of 43.8% and a live birth rate of 34.4%, which were significantly lower than NZP group. In addition, the clinical outcomes of frozen embryo transfer (FET) cycles showed no significant differences. Compared to the rescue- intracytoplasmic sperm injection (ICSI) group, ICSI regimen facilitated a substantially higher rates of oocyte fertilization, cleavage, and enhanced efficiency in embryo utilization. Conclusions Patients with IZP had unsatisfactory embryological and fresh embryo transfer outcomes, and it was a favor choice to use ICSI insemination timely. FET might potentially mitigate the impact of ZP abnormalities.