Researchers from Queen’s University in Canada examined obesity as a key factor in stillbirth risk, with the analysis showing higher likelihoods as pregnancy progresses. The findings were published in CMAJ, the Canadian Medical Association Journal, and contribute to a growing understanding of how maternal health conditions influence pregnancy outcomes.
In the study, an extensive review of birth records was conducted, encompassing more than 681,178 births in Ontario. After adjusting for established risk factors such as diabetes and hypertension, the analysis revealed that women whose body mass index falls into the obesity category class I, defined as a BMI of 30 to 34.9, faced about twice the risk of stillbirth at 39 weeks of gestation when compared with pregnant individuals who had a normal BMI between 18.5 and 24.9. This elevated risk persisted even after accounting for other variables, underscoring obesity as a meaningful contributor to late-pregnancy complications.
BMI, a standard measure used to gauge body fat based on weight relative to height, is calculated by dividing a person’s weight in kilograms by the square of their height in meters. This metric helps clinicians assess potential health risks and tailor guidance for expectant mothers as pregnancy advances. The study highlighted a gradient of risk that becomes more pronounced as gestation progresses, with higher obesity classes correlating with greater chances of adverse outcomes in the later weeks of pregnancy.
Further analysis showed that among individuals with more severe obesity, specifically BMI values in the 35 to 39.9 range and those at or above 40, the risk of stillbirth at week 36 was about two to two and a half times higher than in those with normal BMI. The risk continued to rise as the pregnancy approached term, accelerating to more than fourfold by the 40th week. These figures illustrate a clear association between escalating obesity severity and the probability of stillbirth as term nears.
The researchers emphasize that these results may support the development of personalized prenatal counseling for patients who have obesity. By identifying obesity as a modifiable risk factor in pregnancy, healthcare providers can offer targeted strategies, including weight management discussions, nutrition optimization, and careful monitoring, to improve outcomes for both mother and baby. The goal is to integrate these insights into routine obstetric care to better inform decision making and planning throughout gestation.
Previous investigations have explored the relationship between extreme heat exposure and preterm birth, suggesting that environmental conditions may also play a role in pregnancy outcomes. While this line of inquiry is distinct from obesity-related risk, it contributes to a broader understanding of how multiple factors intersect to influence the timing and safety of childbirth. Ongoing research continues to refine how clinicians can translate these insights into practical guidance for expectant families, emphasizing the importance of comprehensive risk assessment and supportive care during pregnancy.