Clinical predictors of embryo quality among women of advanced age receiving intracytoplasmic sperm injection cycles in Malaysia: A cohort study

Background: Declining fertility in a woman of advanced age is associated with a depletion in ovarian reserve as well as declining oocyte and embryo quality. Determining the predictors of embryo quality may assist in stimulation target and cycle prediction.

Objective: This study aims to identify factors affecting embryo quality among women of advanced age receiving intracytoplasmic sperm injection (ICSI) cycles.

Materials and methods: This prospective cohort study was conducted over a period of 12 months, from January until December 2018, on 734 mature oocytes retrieved from 124 women of advanced age (35-45 yr old) receiving ICSI. The Society of Assisted Reproductive Techniques system was used to determine the morphological grading of embryo quality. The fertilization rate, cleavage rate, and pregnancy rate per cycle were expressed as a percentage per cycle for a total of 76 embryo transfers. Possible predictors of high-quality embryos were evaluated using single and multiple regression tests, with p $<$ 0.05 considered as significant.

Results: Out of the 586 available embryos, 288 (49.15%) high-quality embryos were obtained. The fertilization and cleavage rates were 86.18% and 97.83%, respectively. The total number of retrieved oocytes (R² = 0.857) and the total available embryos (R² = 0.857) were closely related to high-quality embryos. 76 embryo transfers were conducted, with 17 successful conceptions (implantation rate = 22.37% per transfer). There were no miscarriages among the pregnancies.

Conclusion: Increasing the number of collected oocytes and the cleavage rate could increase the chance of obtaining more high-grade embryos. This could increase the success of ICSI among women of advanced age.