New research has found that mothers with endometriosis face a slightly increased risk of giving birth to babies with birth defects.
A newly released study by the Canadian Medical Association Journal (CMAJ) analyzed data of more than 1.4 million births in Ontario between April 7, 2006, and March 31, 2021, with 33,619 babies being born to people who had endometriosis.
Of that number, 2,120 babies had a congenital anomaly, representing a 6.3 per cent rate.
Compared to babies born to people without endometriosis, 77,094 had a congenital anomaly, representing a 5.4 per cent rate. The study concluded that “endometriosis in the patient was independently associated with a higher risk of any congenital anomaly.”
“I think what really comes out of this is it’s just so important to investigate and to provide the resources for researchers to look at these issues,” said Dr. Nicholas Leyland, president-elect of the Society of Obstetricians and Gynaecologists of Canada (SOGC).
“This study highlights a good way of looking at these particular diseases to be able to determine how best we can intervene or whether or not there’s anything we can do to prevent these congenital anomalies, a better understanding of inflammation and how it affects pregnancy.”
The study found that “specific anomalies with the highest associated risks included unspecified cleft palate, hypospadias and pulmonary artery stenosis.”
Leyland said that something about the endometriosis and possibly infertility treatment “may be aligned” with the creation of “rare but significant congenital anomalies.”
He also stated that while the increase in congenital anomalies found from the study is notable, it can also be drawn to the nature of endometriosis, which he states is inflammation.
“During pregnancy, it [inflammation] potentially has the influence on the development of organogenesis or as the embryo and the fetus develops, development of the different organ systems,” Leyland said.
President of Endometriosis Canada Violeta Kondovski said that the results of the study “aren’t that shocking to the endometriosis community,” because “many people with endometriosis also have connective tissue disorders, which can be linked to some congenital anomalies.”
According to Endometriosis Network Canada, the condition affects at least one in 10 women in Canada, with almost two million Canadians estimated to have endometriosis.

However, Kondovski said that number could be much higher.
“It could a lot more [people] than we think, we just don’t know because a lot of people don’t the symptoms. They could be either asymptomatic, or they just think their symptoms are normal and they have to deal with it,” she said.