Do you know obesity is a risk factor for stillbirth? Study finds

The study findings were published in the Canadian Medical Association Journal or CMAJ.In Canada, the overall risk of stillbirth during pregnancy is roughly 0.4 per cent. “Our findings suggest that an earlier delivery date may help reduce the risk of stillbirth for pregnant people with obesity,” said lead author Dr. Naila Ramji, an assistant professor at Dalhousie University and high-risk pregnancy specialist in Fredericton, New Brunswick. Senior author Dr. Laura Gaudet, an associate professor at Queen’s University and high-risk pregnancy specialist, and coauthors at The Ottawa Hospital round out the group.

Although the link between obesity and stillbirth is well-known, there was little research on the association between obesity and stillbirth risk by gestational age, or on the impact of higher classes of obesity.To address this gap, the researchers analyzed data from the Better Outcomes Registry and Network on 681 178 singleton births, 1956 of which were stillbirths, in Ontario between 2012 and 2018. After adjusting for other stillbirth risk factors like diabetes and high blood pressure, the researchers found that people with class I obesity (BMI 30-34.9 kg/m2) had double the risk of stillbirth at 39 weeks’ gestation compared to those with normal BMI (18.5-24.9 kg/m2). For those in obesity classes II and III (BMI 35-39.9 kg/m2 and BMI 40 kg/m2 and higher, respectively), stillbirth risk at 36 weeks was 2 to 2.5 times that of people with normal BMI. This risk further increased with gestational age, with a more than fourfold risk at 40 weeks.

“For other medical conditions that increase the risk of stillbirth, there are guidelines that recommend delivery at 38 or 39 weeks. Interestingly, the risk thresholds for those conditions are lower than the risks we found associated with obesity. We worry that implicit biases against people with obesity may be causing the medical community to take the risks they face less seriously,” says Dr. Ramji.

The authors also looked at whether stillbirths occurred before or during delivery and found a higher risk of stillbirths occurring before delivery in people with class I and II obesity.