Embryo quality and pregnancy outcomes in patients with a low ovarian reserve regarding natural cycles Vs. Mildly stimulated cycles

Women with low ovarian reserve who opt for in-vitro fertilization (IVF) treatment need to choose between natural and mildly stimulated cycles. However, the superiority of any one regimen over the other remains unclear. The present study assessed the impact of natural cycles on embryo quality and pregnancy outcomes and also compared it to mildly stimulated cycles.

The study enrolled consecutive patients with low ovarian reserve who underwent IVF/intracytoplasmic sperm injection (ICSI) and compared the pregnancy rate of 478 natural cycles and 448 mild stimulated cycles. It also assessed embryo quality and oocyte retrieval time of natural cycles and found-

• Significantly higher pregnancy rate in the natural cycle group than in the mildly stimulated cycle group. 
• Higher rates of available embryos, high-quality embryos, and utilization of oocytes in natural cycles than mildly stimulated cycles. 
• Oocyte retrievals in natural cycles were mainly conducted between 7:00 and 19:00, with 94.9% occurring during this time frame. 
• In natural cycles with high-quality embryos, 96.4% of oocyte retrievals were also performed between 7:00 and 19:00.

This study shows that natural cycles with appropriately timed oocyte retrieval are a valuable option for patients with low ovarian reserve.

Yuan R-Y, Li S, Feng X, et al. Comparison of embryo quality and pregnancy outcomes for patients with low ovarian reserve in natural cycles and mildly stimulated cycles: a cohort study, Journal of Obstetrics and Gynaecology.2024;44(1). DOI: 10.1080/01443615.2024.2303693