Uterine receptivity impairments may contribute to infertility for women with endometriosis

Key takeaways:

• Women with endometriosis undergoing assisted reproduction had lower live birth rates vs. women without.
• Implantation rates were significantly lower among women with vs. without endometriosis.

Women with vs. without endometriosis using assisted reproductive technology had lower live birth rates, suggesting that uterine receptivity impairments may contribute to infertility mechanisms, researchers reported in JAMA Network Open.

“The concept that the uterine environment of women with endometriosis may affect the embryo implantation process remains controversial. Endometrial changes, primarily or secondarily associated with inflammation related to the disease, are believed to contribute, at least in part, to impaired receptivity,” Alessio Paffoni, PhD, laboratory manager of the infertility unit at Azienda Socio Sanitaria Territoriale (ASST) Lariana in Como, Italy, and colleagues wrote. “This concern may be particularly crucial in donor egg cycles, possibly resulting in lower live birth rate in recipients with endometriosis compared with those with other indications.”

Paffoni and colleagues conducted a meta-analysis of four observational studies and a retrospective analysis of data from the Society for Assisted Reproductive Technology (SART) in the U.S. and the Human Fertilisation and Embryology Authority (HFEA) in the U.K. databases from inception to August 2023. All studies investigated the impact of endometriosis on assisted reproductive technology outcomes with donor oocytes.

Primary outcome was the live birth rate after oocyte donor cycles. Secondary outcomes included clinical pregnancy rates, implantation rates and miscarriage rates for women with and without endometriosis.

The four analyzed studies included 7,212 oocyte donation cycles, and researchers analyzed 137,182 cycles from SART and 24,900 from HFEA. Overall, 958 women had endometriosis.

In an aggregate analysis of data from 6,973 women from three of the studies, of which 903 had endometriosis, researchers observed no significant difference in live birth rate after oocyte donor cycles for women with or without endometriosis (OR = 0.76; 95% CI, 0.52-1.11). In addition, there was no significant difference in live birth rate for women with or without endometriosis after adjusting for confounding factors (adjusted OR = 0.54; 95% CI, 0.19-1.57). However, when pooling and evaluating aggregate data from the SART and the HFEA, women with endometriosis had statistically significantly lower live birth rates (OR = 0.89; 95% CI, 0.81-0.97).

Regarding secondary outcomes, researchers observed significant reductions in implantation rates for women with endometriosis (OR = 0.79; 95% CI, 0.69-0.92) with no effects observed for clinical pregnancy (OR = 0.61; 95% CI, 0.24-1.53) or miscarriage rates (OR = 1.16; 95% CI, 0.42-3.22) compared with women without endometriosis.

“Because this approach can provide insights into the impact of the condition on the process of embryo implantation, we can deduce that a marginal impairment of uterine receptivity contributes to infertility mechanisms in women affected by endometriosis,” the researchers wrote. “Whether this defect is associated with comorbidities or confounders have to be clarified in future studies.”