Study Reveals Higher Congenital Anomaly Risk in Endometriosis

By VirentaNews Staff — May 11, 2026

Infants born to people with endometriosis face an 18% higher risk of being diagnosed with a congenital anomaly—commonly referred to as a birth defect—compared to those without the condition, according to a large-scale study published in the Canadian Medical Association Journal. Analyzing data from over 11 million births in Quebec between 1989 and 2017, researchers found that while the absolute risk remains low, the association is statistically significant and holds across various subtypes of endometriosis, including ovarian, peritoneal, and deep infiltrating forms. Given that endometriosis affects roughly 10% of reproductive-age individuals worldwide, the findings suggest that even a modest increase in risk could translate to thousands of additional cases of congenital anomalies annually, underscoring the need for enhanced prenatal surveillance and counseling for this population.

Why This Matters Now

Endometriosis, a chronic inflammatory condition where tissue similar to the uterine lining grows outside the uterus, has long been associated with infertility and chronic pelvic pain. However, its impact on pregnancy outcomes—particularly fetal development—has remained less clear. With rising global awareness and diagnosis rates of endometriosis, and more individuals delaying pregnancy into their 30s and beyond, understanding the full spectrum of reproductive risks is increasingly urgent. This study arrives at a pivotal moment when reproductive health research is shifting toward long-term maternal and infant outcomes, not just fertility success. The findings reinforce that endometriosis is not merely a gynecological disorder but a systemic condition with potential intergenerational health implications, warranting integration into prenatal risk assessment frameworks.

Key Findings and Study Scope

The Quebec-wide retrospective cohort study included 11,166,950 singleton births, of which 44,149 were to individuals diagnosed with endometriosis. After adjusting for maternal age, socioeconomic status, comorbidities, and fertility treatments, researchers found a consistent 18% increase in congenital anomalies among infants born to endometriosis patients. Specific anomalies included cardiovascular defects, urogenital malformations, and digestive system abnormalities. Notably, the elevated risk was observed regardless of whether conception occurred naturally or through assisted reproductive technology (ART), suggesting that the underlying pathophysiology of endometriosis—not just fertility interventions—may play a role. The study also showed that the risk was slightly higher in cases of deep infiltrating endometriosis, the most severe form of the disease.

Biological Mechanisms and Expert Analysis

While the study does not establish causation, researchers propose several biological pathways that may explain the link. Chronic inflammation, a hallmark of endometriosis, could disrupt early embryonic development by altering the uterine environment or affecting oocyte quality. Additionally, hormonal imbalances—particularly elevated estrogen levels—and oxidative stress associated with endometriotic lesions may interfere with fetal organogenesis. Some experts also speculate that epigenetic changes in the endometrium of affected individuals could influence gene expression during critical windows of fetal development. According to Dr. Sonya Kashinskie, lead author of the study, “The endometrial receptivity in endometriosis patients may be compromised, which could have downstream effects on implantation and placental formation—both vital for healthy fetal growth.” These mechanisms align with broader research linking maternal inflammatory conditions to adverse pregnancy outcomes.

Implications for Patients and Providers

The findings have immediate implications for clinical practice. Obstetricians and reproductive endocrinologists may need to consider endometriosis as a risk factor during prenatal screening discussions, particularly when planning ultrasound timelines and genetic testing. While the absolute risk of congenital anomalies remains under 5%—rising from approximately 2.8% to 3.3% in the study—this information can empower patients to make informed decisions. For individuals with severe endometriosis contemplating pregnancy, earlier and more frequent fetal anomaly scans may be warranted. Moreover, the results highlight the importance of preconception counseling, where managing inflammation, optimizing metabolic health, and addressing nutritional deficiencies could potentially mitigate some risks, though further research is needed to confirm such interventions.

Expert Perspectives

While the study is lauded for its scale and methodological rigor, some experts urge cautious interpretation. Dr. Hugh Taylor, Chair of Obstetrics, Gynecology, and Reproductive Sciences at Yale School of Medicine, noted, “This is an important association, but we must avoid alarming patients. Most babies born to people with endometriosis are healthy.” Others point out that unmeasured confounders—such as medication use or undiagnosed autoimmune conditions—could partially explain the link. Conversely, reproductive specialists like Dr. Togas Tulandi from McGill University emphasize that the data should prompt greater integration of endometriosis history into maternal-fetal medicine guidelines, stating, “We’re beginning to see endometriosis not just as a cause of pain or infertility, but as a condition with broader reproductive consequences.”

Looking ahead, researchers call for prospective studies to explore whether treating endometriosis prior to conception—through surgery, hormonal therapy, or anti-inflammatory strategies—can reduce the risk of congenital anomalies. Additionally, investigations into biomarkers that predict fetal risk could lead to personalized prenatal care pathways. As global healthcare systems grapple with rising rates of endometriosis and delayed childbearing, understanding and mitigating these intergenerational health effects will be critical to improving outcomes for both mothers and babies.

Source: MedicalXpress