Impact of Obesity on Outcomes of Pregnancy in Women With Heart Disease

Background: Women with heart disease are at risk for complications during pregnancy. This study sought to examine the effect of maternal obesity on pregnancy complications in women with heart disease.

Objectives: The objective was to determine the incidence of adverse cardiac events (CE) in pregnant women with heart disease and obesity.

Methods: Adverse CE during pregnancy were examined in a prospective cohort of women with heart disease. CE were a composite of the following: cardiac death/arrest, arrhythmias, heart failure, myocardial infarction, stroke, aortic dissection, and thromboembolic events. Pre-eclampsia and post-partum hemorrhage were also studied. Outcomes were examined according to body mass index (BMI). To identify additional predictors of CE, a baseline risk score (CARPREG [Canadian Cardiac Disease in Pregnancy Study] II score) for predicting cardiac complications was calculated for all pregnancies and included in a multivariable logistic regression model.

Results: Of 790 pregnancies, 19% occurred in women with BMI ≥30 kg/m² (obesity), 25% in women with BMI 25 to 29.9 kg/m² (overweight), 53% in women with BMI 18.5 to 24.9 kg/m² (normal weight), and 3% in women with BMI <18.5 kg/m² (underweight). Women with obesity were at higher risk of CE when compared with women with normal weight (23% vs. 14%; p = 0.006). In a multivariable model, obesity (odds ratio: 1.7; 95% confidence interval: 1.0 to 2.7) and higher CARPREG II risk scores (odds ratio: 1.7; 95% confidence interval: 1.5 to 1.9) predicted CE. Pre-eclampsia was more frequent in women with obesity compared with those with normal weight (8% vs. 2%; p = 0.001).

Conclusions: Obesity increases the risk of maternal cardiovascular complications in pregnant women with heart disease. This modifiable risk factor should be addressed at the time of preconception counseling.