Endometriosis Linked to Higher Birth Defect Risk, New Canadian Study Finds

A major Canadian study has found that mothers living with endometriosis face a modestly elevated risk of having babies born with congenital anomalies adding fresh urgency to calls for greater research funding and awareness around a condition that affects millions.

The study, published by the Canadian Medical Association Journal, drew on data from over 1.4 million births recorded in Ontario between 2006 and 2021. Among those births, more than 33,600 were to people diagnosed with endometriosis. Researchers found that 6.3 per cent of those babies were born with a congenital anomaly, compared to 5.4 per cent among babies born to those without the condition a difference that led the study to conclude endometriosis is independently associated with a heightened risk of birth defects.

The specific anomalies most closely tied to the condition included unspecified cleft palate, hypospadias, and pulmonary artery stenosis.

For many in the endometriosis community, the findings landed less as a bombshell and more as a confirmation of something long suspected.

“The results aren’t that shocking to the endometriosis community,” said Violeta Kondovski, President of Endometriosis Canada. “Many people with endometriosis also have connective tissue disorders, which can be linked to some congenital anomalies.”

Still, Kondovski was clear that the study matters not to alarm women, but to finally shine a light on a condition she says has been chronically underfunded and under-researched for decades.

“It’s not just bad periods,” she said. “It damages our organs, you can lose organs, we lose our fertility, we have miscarriages because of it it just affects our lives so much. We hope something changes soon.”

Dr. Nicholas Leyland, president-elect of the Society of Obstetricians and Gynaecologists of Canada, pointed to inflammation a hallmark feature of endometriosis as a likely factor in the association.

“During pregnancy, it potentially has the influence on the development of organogenesis,” he explained, referring to the process by which a fetus develops its organ systems. He also noted that infertility treatments, which are more common among those with endometriosis, may play a contributing role though more research is needed to untangle exactly what is driving the elevated risk.

Despite the findings, Leyland was careful to stress that the numbers should not send expectant mothers into panic.

“We wouldn’t want to frighten them,” he said. “But we would say that we’re going to do the same testing and screening that’s available to us now to pick up issues as they arise and then deal with them as necessary when the baby is born.”

Part of what makes this research so significant is how widely and quietly endometriosis affects people. According to Endometriosis Network Canada, at least one in ten women in the country lives with the condition, with close to two million Canadians estimated to be affected.

But Kondovski believes the real number could be far higher, largely because so many go undiagnosed.

“A lot of people don’t recognise the symptoms,” she said. “They could be asymptomatic, or they just think their symptoms are normal and they have to deal with it.”

She pointed to a deeply ingrained cultural pattern of normalising pain particularly menstrual pain that leads many women to dismiss symptoms that warrant medical attention.

“Some people are taught by their families that some women just have tougher periods,” she said. “And unfortunately, that’s passed down so often that it’s taking forever for anyone to get diagnosed because they don’t know what’s wrong.”

On a more hopeful note, a separate study out of Oxford University, published in April 2026, has identified a promising new direction for diagnosis. A specialised CT scan trial was able to correctly detect the presence or absence of endometriosis in 16 out of 19 women and demonstrated accuracy in identifying lesions that conventional imaging routinely misses.

The researchers behind the so-called DETECT study called it the first minimally invasive diagnostic technique of its kind, underscoring an urgent need for better tools given how heavily current diagnosis relies on invasive surgical procedures.

For Kondovski, both studies point in the same direction: toward a condition that has long deserved more attention than it has received.

“We know that endometriosis is already a full body condition, that it has a greater chance of being passed down through our children,” she said. “We just don’t have all the learnings because there hasn’t been very much research.”

With studies like these beginning to map the broader implications of the disease, advocates and clinicians alike are hoping the momentum for change is finally building.