Infertility, not just treatment, may shape birth outcomes, finds study of 1.4M births

Toronto, ON, August 12, 2026 — Infertility is the inability to conceive after 12 months of regular, unprotected sexual intercourse; some patients with infertility are still able to conceive without fertility treatment. Infants born to those with infertility face a higher risk of congenital anomalies compared to unassisted conception, according to a new study from ICES, Queen’s University, and the Research Institute of the McGill University Health Centre.

In the study of 1,415,324 births, 1,185,299 were conceived without assistance and 230,025 by women with infertility who did not use treatment. Among these births the prevalence of congenital anomalies was 5.3 per cent in infants from unassisted conceptions compared with 5.9 per cent in the latter cohort. Some of these observed anomalies include cleft palates, heart defects, and kidney malformations.

The findings suggest that, although the risk of congenital anomalies was low, there was an increased risk for infants born to women with infertility but did not use fertility treatment to conceive.

“Our intention is not to alarm expecting mothers. Rather, we should consider how the underlying causes of infertility—such as endometriosis, polyendocrine metabolic ovarian syndrome (PMOS, formerly known as PCOS), paternal factors, and others—may influence fetal development, so that future research can better understand the biological mechanisms underlying these associations and identify opportunities to improve maternal and child health,” says Bailey Milne, lead author of the study and an ICES doctoral student.

Past research compared pregnancies conceived through fertility treatments with unassisted conceptions, capturing both treatment effects and underlying fertility on congenital anomalies. However, the same reproductive issues that prompt individuals to seek fertility treatment may themselves influence this risk. For example, endometriosis is a well-established cause of infertility, and recent work from the team suggests that it may also be associated with an increased risk of congenital anomalies in offspring.

“As the proportion of births conceived through fertility treatment technologies continues to grow, studies evaluating the safety of existing and emerging fertility technologies should compare these pregnancies with those conceived by patients with infertility who did not undergo fertility treatment,” adds Dr. Maria Velez, senior author, Scientist at The Institute, and Associate Professor, Department of Obstetrics and Gynecology, Faculty of Medicine and Health Sciences, McGill University.

The study “Infertility and risk of congenital anomalies: a population-based cohort study” is in the August issue of Paediatric and Perinatal Epidemiology. 
 

ICES is an independent, not-for-profit research and analytics institute that uses population-based health information to produce knowledge on a broad range of healthcare issues. ICES leads cutting-edge studies and analyses evaluating healthcare policy, delivery, and population outcomes. Our knowledge is highly regarded in Canada and abroad and is widely used by government, hospitals, planners, and practitioners to make decisions about healthcare delivery and to develop policy. For the latest ICES news, follow us on Facebook and LinkedIn: @ICESOntario     

About Queen’s University   
Queen’s University has a long history of scholarship, discovery, and innovation that shapes our collective knowledge and helps address some of the world’s most pressing concerns. Home to more than 28,000 students, Queen’s offers a comprehensive research-intensive environment. Diverse perspectives and a wealth of experience enrich our students and faculty while a core part of our mission is to engage in international learning and research.   

In 2025, for the fifth year in a row, Queen’s University has ranked in top 10 globally of the Times Higher Education Impact Rankings, securing the position of 6th worldwide and 1st in Canada. The rankings measured over 2,500 post-secondary institutions from 130 countries on their work to advance the United Nations’ Sustainable Development Goals (SDGs).  

About the Research Institute of the McGill University Health Centre
The Research Institute of the McGill University Health Centre (The Institute) is a world-renowned biomedical and healthcare research centre. Affiliated with the Faculty of Medicine and Health Sciences of McGill University, The Institute is the research arm of the McGill University Health Centre (MUHC)-an academic health centre located in Montreal, Canada, that has a mandate to provide complex care to its community. The Institute supports over 700 researchers and close to 1,500 research trainees devoted to a broad spectrum of fundamental, clinical and health outcomes research at the Glen and the Montreal General Hospital sites of the MUHC. Its research facilities, including the Centre for Translational Biology, the Centre for Innovative Medicine and the Centre for Outcomes Research and Evaluation, offer a dynamic multidisciplinary environment that fosters collaboration and leverages discovery aimed at advancing precision health throughout the life course. The Institute is supported in part by the Fonds de recherche du Québec (FRQ). rimuhc.ca

FOR FURTHER INFORMATION PLEASE CONTACT:     
Charlotte Lam     
Communications Associate    
ICES      
[email protected]    
437-317-8804   

Julie Brown  
Media Relations Manager  
Queen’s University  
[email protected]  
613-533-2035  

Fabienne Landry
Communications Coordinator
Research, MUHC
[email protected]
514-812-7722