Obesity increases cardiovascular risk from pregnancy complications

Pregnancy complications increase short- and long-term cardiovascular risks among obese individuals, according to a recent study published in Circulation Research.

An adverse pregnancy outcome (APO) is reported in about 1 in 4 pregnancies. These include hypertensive disorder of pregnancy, preterm birth, gestational diabetes, and small for gestational age. 

APOs are associated with increased maternal morbidity and mortality, and recent data has suggested a potential association between APOs and cardiovascular disease (CVD) risk. Shared risk factors, such as increased body mass index (BMI) prepregnancy, have been hypothesized as sources of this association.

This data was obtained from nulliparous individuals and was limited in follow-up, requiring additional studies. Investigators conducted a study to determine the association between maternal obesity, hypertensive disorders of pregnancy, and cardiovascular health.

Participants were recruited across 8 US clinical centers from 2014 to 2017. Eligibility criteria included being nulliparous, aged 18 years or older, with a singleton pregnancy, and not having a history of prepregnancy hypertension or diabetes. Exclusion criteria included stillbirth, induced abortion, or spontaneous abortion.

Height and weight were measured at baseline, with BMI calculated as weight in kg divided by height in meters squared. Normal BMI was measured as BMI under 25 kg/m2, overweight as BMI 25 kg/m2 to under or equal 30 kg/m2, and obese as BMI above or equal 30 kg/m2.

Hypertensive disorders of pregnancy, including preeclampsia, eclampsia, and gestational hypertension, were the primary mediator in the analysis. Development of CVD risk factors was the primary outcome, measured in 3 cardiometabolic domains: hypertension, hyperlipidemia, and diabetes.

Covariates evaluated at baseline included race and ethnicity, maternal age, smoking status, insurance type, dietary quality, physical activity, perceived stress, depression, sleep duration, and CVD risk factor levels. In the sensitivity analysis, gestational weight gain was also included as a covariate.

There were 4216 pregnant individuals included in the final analysis, with an average gestational age of 11.4 weeks. A normal BMI was reported in 53% of patients, overweight in 25%, and obesity in 22%. The average gestational duration and birthweight were 39 weeks and 3.3 kg respectively.

Hypertensive disorders of pregnancy were reported in 15% of patients, with 9% having preeclampsia or eclampsia and 6% having gestational hypertension. Preterm birth was reported in 8% of patients, small for gestational age birth in 11%, and gestational diabetes in 4%.

The risk of hypertensive disorders of pregnancy was increased in overweight and obese patients, with adjusted odds ratios of 1.64 and 2.34 respectively compared to patients with a normal BMI. Hypertensive disorders were associated with increased incident hypertension risk and hyperlipidemia.

An association was also found between hypertensive disorders of pregnancy and systolic blood pressure and total cholesterol levels. Incident hypertension, hyperlipidemia, and diabetes risks were also increased in patients with preterm birth. Overall, the risks of hypertension, hyperlipidemia, and diabetes at follow-up were increased in overweight and obese patients.

These results indicated an association between pregnancy complications and CVD risk factors among overweight and obese patients. Investigators recommended prepregnancy or early pregnancy interventions be implemented before an APO occurs.

Reference

Khan SS, Petito LC, Huang X, et al. Body mass index, adverse pregnancy outcomes, and cardiovascular disease risk. Circulation Research. 2023;133(9):725–735. doi:10.1161/CIRCRESAHA.123.322762