Can endometriosis cause recurrent pregnancy losses?

From the Guidelines

Yes, endometriosis can potentially contribute to recurrent pregnancy losses. Endometriosis is a condition where tissue similar to the uterine lining grows outside the uterus, affecting approximately 10% of women of reproductive age, as noted in a study published in the Journal of the American College of Radiology in 2020 1. This condition can impact fertility and pregnancy outcomes through several mechanisms, including inflammation in the pelvis, alteration of the immune environment, creation of anatomical distortions, or affectation of implantation quality.

Some key points to consider about endometriosis and its impact on fertility and pregnancy outcomes include:

• Endometriosis affects at least one-third of women with infertility and up to 10% of reproductive-aged women 1.
• The mechanism by which endometriosis is associated with infertility is unclear, but it may involve factors such as inflammation, immune dysfunction, and anatomical distortions 1.
• Women with endometriosis may have a higher risk of miscarriage, although the exact risk increase is not well quantified in the provided studies.
• Treatment options for endometriosis-related infertility and recurrent pregnancy loss may include hormonal therapies, surgical removal of endometriotic lesions, or assisted reproductive technologies.

It is essential to work with both a reproductive endocrinologist and an endometriosis specialist to develop a personalized treatment plan, as the management of endometriosis and its impact on fertility and pregnancy outcomes can be complex and require a multidisciplinary approach. Managing endometriosis effectively before conception may improve the chances of a successful pregnancy, as suggested by the American College of Obstetricians and Gynecologists (ACOG) in recommendations published in 2000 1. However, the most recent and highest-quality evidence should be prioritized in guiding treatment decisions, and the provided studies from 2000 may not reflect the current standard of care.

From the Research

Endometriosis and Recurrent Pregnancy Loss

• Endometriosis has been associated with pregnancy loss and recurrent pregnancy loss (RPL) in several studies 2, 3.
• A nationwide historical cohort study found that women with endometriosis had a higher odds ratio of experiencing pregnancy loss and RPL compared to women without endometriosis 2.
• The study found that 18.9%, 3.9%, and 2.1% of ever-pregnant women with endometriosis had 1,2, and ≥ 3 pregnancy losses, respectively, compared to 17.3%, 3.5%, and 1.5% of women without endometriosis 2.

Factors Associated with Recurrent Pregnancy Loss in Endometriosis

• Chronic inflammatory processes affecting the endometrium, such as those encountered in endometriosis, adenomyosis, and chronic endometritis, may alter endometrial receptivity and contribute to RPL 3.
• Other factors associated with endometriosis, such as intrapelvic inflammatory processes, may also impact oocyte and embryo quality and contribute to miscarriages and RPL 3.

Treatment Options for Endometriosis and Recurrent Pregnancy Loss

• Laparoscopic surgery combined with GnRH agonist has been shown to be an effective treatment modality for endometriosis, reducing serum levels of inflammatory factors, improving hormone levels, and increasing pregnancy rates 4.
• Comparison of ovulation induction protocols after endometrioma resection found that long GnRH-a and GnRH-ant protocols had similar IVF outcomes in patients with endometriosis 5.

Contrasting Findings

• A study from 2000 found no evidence that endometriosis is associated with recurrent pregnancy loss or that medical or surgical treatment of endometriosis reduces the spontaneous abortion rate 6.
• However, this study had methodological limitations, and more recent studies have found an association between endometriosis and RPL 2, 3.