The Role of Cumulus Cells for The Immature Oocyte Undergoing In Vitro Maturation Rescue: A Retrospective Analysis

Lack of matured oocytes after ovarian stimulation for in vitro fertilization (IVF) is one problem affecting the number of good-quality embryos. In vitro maturation (IVM) rescue is one way that can be done to rescue the immature oocytes retrieved after ovarian stimulation. It has been proven that cumulus cells (CCs) play an essential role in the growth and development of oocytes. However, their role in immature oocytes undergoing IVM rescue still needs to be improved. To assess the role of CCs in immature oocytes after controlled ovarian stimulation (COS) that underwent IVM rescue followed by intra cytoplasmic sperm injection (ICSI).

A retrospective study consists of 200 immature oocytes with normal morphology obtained from IVF patients who had undergone ovarian stimulation. They were randomly divided into a control group (complete denudation, n=100) and a study group (non-denudation, n=100). Both groups then underwent IVM rescue for 24 hours. Oocytes that mature through IVM rescue were followed by ICSI. Our primary outcome is the number of good-quality embryos. Other intermediate outcomes such as oocyte maturation rate, fertilization rate, embryo cleave and rate, and embryo quality were also analyzed.

The two groups had no significant difference in oocyte maturation rate 71 vs. 73% (P=0.875). However, significant differences were found in the fertilization rate 38.1 vs. 61.6% and embryo cleave rates 37.1 vs. 62.2% (P=0.006 and 0.005, respectively). In addition, immature oocytes that underwent IVM rescue with attached CCs produced more good embryos compared to IVM rescue of denuded oocytes 20 vs. 35.7% (P=0.003).

Current research indicates that IVM rescue of immature oocytes with attached CCs may produce more good-quality embryos.