Maternal and infant health at increased risk if mother has an intellectual or developmental disability: largest study to date

A new study from the Institute for Clinical Evaluative Sciences (ICES) and Women’s College Research Institute has shown that women with intellectual and developmental disabilities are at higher risk for many complications from pregnancy and birth, as are their babies.

The study, published today in BJOG: An International Journal of Obstetrics & Gynaecology (BJOG), is the largest and most comprehensive to look at maternal and infant outcomes for this vulnerable population. Additionally, its study size enabled the researchers to examine somewhat rare but serious outcomes that have not been previously tracked in this population.

“We’ve known for some time that women with intellectual and developmental disabilities commonly experience physical and sexual abuse, unstable living situations, and low social support," says Hilary Brown, lead author on the paper who is a post-doctoral ‎fellow at Women's College Research Institute and at ICES. "We also know that there may be other lifestyle and genetic factors at play in their maternal health, as well as barriers to following medical advice. We conducted this study to see if having an intellectual or developmental disability carries extra risk for a woman’s health during pregnancy and birth, or for that of her baby. And indeed, this very large study shows through multiple indicators that it does.”

The study looked at singleton birth records for Ontario women aged 18 to 49 between 2002 and 2011. The researchers split the records into two groups: 3,932 deliveries for women with intellectual and developmental disabilities, and 382,774 without. Because women with intellectual and developmental disabilities are more likely to live in the poorer neighbourhoods and to have pre-existing diabetes, epilepsy, and psychiatric disorders, the researchers took the additional step of adjusting their findings to account for these impacts. Even after adjusting, they found that women with intellectual and developmental disabilities continue to be at much higher risk for negative birth outcomes, as were their babies.

MATERNAL RISK – The study showed higher maternal risks for women with intellectual and developmental disabilities that included preeclampsia (almost 50 per cent higher risk, with a rate of 1.5 per cent in the affected population compared to 1 per cent in the non-affected population); venous thromboembolism (a 60 per cent higher risk at 1.1 per cent compared to 0.7 per cent); peripartum hemorrhage (a 30 per cent higher risk at 6.1 per cent compared to 4.6 per cent) and severe obstetric morbidity (a 40 per cent higher risk at 2.7 per cent compared to 1.9 per cent). However, the rates of gestational diabetes and gestational hypertension were slightly lower for these women. 

INFANT RISK – Babies born to women with intellectual and developmental disabilities were seen to be at increased risk for preterm birth (a 63 per cent higher risk, with a rate of 10.9 per cent compared to 6.3 per cent of babies born to non-affected mothers) and being small for gestational age (a 35 per cent higher risk, at 17.5 per cent of births compared to 12.1 per cent). Additionally, the rates of stillbirth, neonatal mortality and neonatal morbidity were nearly twice as high or more for these births. 

“Giving birth continues to be a very safe procedure in Ontario and the numbers of complications are quite low overall for mothers and babies,” comments Dr. Simone Vigod, the senior author on the paper who is an adjunct scientist at ICES and a scientist at Women’s College Research Institute. “However, for this vulnerable population, there are clearly extra risks. Based on these findings, we suggest that women with intellectual and developmental disabilities should receive additional supportive and specialized prenatal care. This added support will most certainly result in better safety and health for these women, as well as for their babies.”

The study “Maternal and offspring outcomes in women with intellectual and developmental disabilities: a population-based cohort study” was published today in BJOG: An International Journal of Obstetrics & Gynaecology (BJOG).

Author block: Hilary K. Brown, Virginie Cobigo, Yona Lunsky, Simone N. Vigod.

The Institute for Clinical Evaluative Sciences (ICES) is an independent, non-profit organization that uses population-based health information to produce knowledge on a broad range of healthcare issues. Our unbiased evidence provides measures of health system performance, a clearer understanding of the shifting healthcare needs of Ontarians, and a stimulus for discussion of practical solutions to optimize scarce resources. ICES knowledge is highly regarded in Canada and abroad, and is widely used by government, hospitals, planners, and practitioners to make decisions about care delivery and to develop policy. For the latest ICES news, follow us on Twitter: @ICESOntario

About Women’s College Hospital – For more than 100 years Women’s College Hospital (WCH) has been developing revolutionary advances in healthcare. Today, WCH is a world leader in the health of women and Canada’s leading, academic ambulatory hospital. A champion of equitable access, WCH advocates for the health of all women from diverse cultures and backgrounds and ensures their needs are reflected in the care they receive. It focuses on delivering innovative solutions that address Canada’s most pressing issues related to population health, patient experience and system costs. The WCH Institute for Health System Solutions and Virtual Care (WIHV) is developing new, scalable models of care that deliver improved outcomes for patients and sustainable solutions for the health system as a whole. Women’s College Research Institute (WCRI) is tackling some of the greatest health challenges of our time. Its scientists are conducting global research that advances the health of women and improves healthcare options for all, and are then translating those discoveries to provide much-needed improvements in healthcare worldwide. For more information about how WCH and WCRI are transforming patient care, visit www.womenscollegehospital.ca and www.womensresearch.ca

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