Poor ovarian response to stimulation linked to higher rates of oocyte cryopreservation use

Key takeaways:

• Women with poor vs. normal response to ovarian stimulation were more likely to use their frozen eggs.
• Having fewer than five vitrified oocytes was linked to higher odds of using them.

Women with poor ovarian response to stimulation had higher likelihood of using frozen oocytes after planned cryopreservation vs. women normal response, particularly among women aged 30 to 39 years, according to cohort study results.

“Importantly, while undergoing planned oocyte cryopreservation, not all individuals experience a response to ovarian stimulation that aligns with their prospective family planning, be it for a desired family size or even the birth of a single child,” Yuval Fouks, MD, MPH, research fellow at the Boston IVF-Eugin Group and the Harvard T. H. Chan School of Public Health, and colleagues wrote in JAMA Network Open. “This indicates that some may not attain the necessary oocyte quality and quantity pivotal for their family building aspirations. These individuals are labeled as ‘poor responders,’ a term that lacks a clear definition.”

Using data from the Society for Assisted Reproductive Technology (SART) Clinic Outcome Reporting System (CORS), Fouks and colleagues identified 47,363 women (mean age, 34.5 years) who had 67,893 autologous oocyte freezing cycles in the U.S. performed from 2014 to 2020. Researchers examined the association between the number of cryopreserved oocytes and the returned rate to utilize cryopreserved oocytes and the time from vitrification to warming.

Overall, 13.5% of women were classified as poor ovarian responders (mean age, 36.8 years) with fewer than five oocytes vitrified across all ovarian stimulation cycles. Overall, 2.5% of women returned for oocyte warming and utilization.

The rate of return was higher among women with poor ovarian response compared with normal responders (4% vs. 2.3%; P < .001). Researchers noted that this rate of return trend was most notable among women aged 30 to 34 years (16.7% vs. 8.4%; P < .001) and women aged 35 to 39 years (21.1% vs. 14.9%; P < .001) compared with other age groups.

Time from vitrification to warming was similar between women with poor ovarian response and normal responders (716.1 vs. 803.8 days).

When adjusting for age, U.S. clinical region, BMI and endometriosis history, researchers observed that having fewer than five vitrified oocytes was associated with higher odds of utilizing them (OR = 1.52; 95% CI, 1.32-1.76).

“Given the heightened likelihood of poor responders using their cryopreserved oocytes, one may advocate for poor responders to undergo additional stimulation cycles to enhance their oocyte reserve, in line with the practical outcomes presented in prior studies,” the researchers wrote. “This strategy could potentially lead to improved success rates for these patients.”