Much Pregnancy-related CVD Risk Associated with BMI, BP

Eirin Beate Haug, PhD

Results of a prospective cohort study of parous women found that 77% of the excess cardiovascular disease risk for women with a history of hypertensive disorders of pregnancy (HDP) is due to blood pressure and body mass index.

“Blood pressure plays a substantial role in driving the excess cardiovascular risk in women who experienced preeclampsia and an even larger role in women who experienced gestational hypertension,” wrote the study authors led by Eirin Beate Haug, PhD, K.G. Jebsen Center for Genetic Epidemiology, Department of Public Health and Nursing, Norwegian University of Science and Technology, Trondheim, Norway.

The authors noted that several previous studies have established that women with a history of HDP have about double the risk of cardiovascular disease (CVD) as women with normotensive pregnancies. However, they added that identifying which factors this excess risk is associated with is important for developing preventive measures.

This study examined the risk factors of body mass index (BMI), blood pressure (BP), glucose levels, and lipid levels in 23,885 women participating in the HUNT study. Authors linked data from the HUNT study, the Medical Birth Registry of Norway, the Norwegian Cause of Death Registry, and validated cardiovascular events from the local hospitals.

For this study, women with HDP were those who had ever experienced preeclampsia or gestational hypertension at ≥40 years of age. Among participants, 2119 (9%) had a history of HDP, 1391 experienced preeclampsia at least once, and 728 experienced only gestational hypertension.

During the median follow-up period of 18 years, 1688 participants experienced at least 1 CV event and 1565 (92.7%) had a validated CV event. Of the 1688 participants, 553 had a myocardial infarction, 233 had heart failure, and 878 had a cerebrovascular event. The authors adjusted hazard ratios for age, maternal birth year, highest educational level, ever daily smoking, parity before age 40 years, and family history of coronary heart disease in sibling or parents.

Women between 40 and 70 years of age with a history of HDP had a higher risk of experiencing any CV event (HR, 1.57; 95% CI, 1.32-1.86; P <.001) than participants without any history of HDP. For the same comparison, women with previous preeclampsia (HR, 1.66; 95% CI, 1.34-2.06; P <.001) and women with previous gestational hypertension (HR, 1.43; 95% CI, 1.09-1.88; P = .01) had higher risk as well.

For women over the age of 70 years, however, the association was reversed but not statistically significant—those with a history of HDP had a lower risk of CV event (HR, 0.60; 95% CI, 0.34- 1.04; P = .07) than women with only normotensive pregnancies. This apparent reversal may be the result of survivor bias, according to the investigators.

For participants 40 to 70 years of age, 41% of the association between HDP and cardiovascular disease was associated with BMI (HR 1.19; 95% CI, 1.07-1.33; P =.001). Systolic BP was associated with 60% (HR 1.30; 95% CI, 1.16-1.47) and diastolic BP with 73% (HR 1.38; 95% CI, 1.23-1.55) of the association between HDP and CVD (P <.001 for both).

When investigators analyzed BMI and blood pressure jointly, they found that BMI and systolic BP were associated with 67% of the HDP and CVD association while BMI and diastolic BP were associated with 79% (P <.001 for both).

“The association of conventional risk factors, in particular blood pressure and BMI, with the development of CVD in women with history HDP indicate that preventive efforts aimed at decreasing the levels of these risk factors could reduce cardiovascular risk in women with history of HDP,” wrote Haug et al.

The study, “Association of Conventional Cardiovascular Risk Factors With Cardiovascular Disease After Hypertensive Disorders of Pregnancy,” was published in JAMA Cardiology.