The Effects of Minimal Stimulation Protocol on Preimplantation Genetic Screening

Background/Objectives: Preimplantation genetic screening improves embryo selection in intracytoplasmic sperm injection cycles, especially for women of advanced maternal age. As chromosomal normality declines with age, high-dose gonadotropins are commonly used to enhance follicular response. This study compares minimal and high-dose stimulation protocols in terms of euploidy, pregnancy, and live birth rates following single embryo transfer. Methods: In this prospective study, 198 women aged 38-45 years were enrolled and divided into two groups: minimal stimulation (100 mg clomiphene citrate and 75 IU human menopausal gonadotropin) and high stimulation (300-450 IU gonadotropins). Women with severe male factor infertility, endometriosis, or absolute tubal factor were excluded. Clinical outcomes were compared using a t-test or Mann-Whitney U test. Results: Baseline characteristics were similar between groups. The high-dose group had a significantly higher number of retrieved oocytes (p = 0.009) and metaphase II oocytes (p = 0.003). However, there were no significant differences in euploid embryo rates (35.4% vs. 37.4%, p = 0.768), clinical pregnancy rates (67.6% vs. 69.4%, p > 0.999), gestational sac rates (58.8% vs. 58.3%, p > 0.999), or live birth rates (47.1% vs. 50.0%, p = 0.995). Conclusions: This is the first prospective study to compare euploid embryo rates, pregnancy rates, and live birth rates between minimal stimulation protocol and high stimulation protocol in AMA patients. Although there has been no difference in euploid and pregnancy rates, minimal stimulation protocol has advantages in cost and comfort.