During the process of embryo development, endometrial receptivity is very important for the successful implantation of blastocysts. This research investigated the influence of endometrial thickness on the day of oocyte retrieval and fresh embryo transfer on pregnancy outcomes in Iraqi women who are undergoing intracytoplasmic sperm injection (ICSI). Women from Iraq are taking part in this investigation. Participating in in vitro fertilization (IVF) cycles with the use of ICSI was a group of 44 women who were diagnosed with polycystic ovarian syndrome (PCOS) and had unexplained infertility. During the phases of oocyte retrieval and embryo transfer, there were significant differences seen between the two groups (p-values of 0.003 and 0.049), respectively. There was a total of 44 individuals, and 31 of them had negative pregnancy test results. The remaining 13 persons had positive findings. These results illustrate the importance of endometrial thickness in influencing the effectiveness of assisted reproductive technologies in achieving pregnancies.