Pregnancy complications such as preeclampsia and gestational diabetes have recently been associated with a higher risk of developing heart disease later in life. But a new Northwestern Medicine study has found obesity before or during pregnancy is the actual root cause of future cardiovascular disease.
Prior to this study, scientists were unsure which factor — obesity or pregnancy complications — played a larger role in cardiovascular disease risk years after pregnancy. This large, multi-center and diverse study is the first to disentangle that question, ultimately determining that pre-pregnancy obesity is the true driver of both poor pregnancy outcomes and future cardiovascular disease risk. It is one of the only studies to follow its participants — about half of whom were overweight or had obesity — from the beginning of their first pregnancy through several years postpartum.
The study used data from the nuMoM2b Heart Health Study to prospectively follow 4,216 first-time pregnant individuals from the early stages of their pregnancy to an average of 3.7 years postpartum. At the early-pregnancy first study visit, the average maternal age was 27 years old, and 53% had a normal body mass index (BMI), 25% were overweight and 22% had obesity. Compared to those with a normal BMI in early pregnancy, individuals with overweight or obese BMI had a higher risk of developing hypertensive disorders of pregnancy.
A major throughline of Khan’s research is the idea of the “Zero trimester,” or pre-pregnancy health. By improving health during this critical time in an individual’s life, they can improve outcomes for not only their pregnancy and baby but for their personal long-term health, Khan said.
However, it can be difficult to target people before becoming pregnant, Khan said. So, early in the pregnancy may be an opportune time to counsel on heart-healthy habits like diet and exercise when people are more likely to be interacting with clinicians during prenatal visits.
Pregnant individuals can safely limit their weight gain throughout pregnancy by eating healthy and exercising moderately or even vigorously, studies have shown.
Approximately 15% of all participants experienced a complication related to high blood pressure; 11% had a baby with a low birthweight; 8% had a preterm birth; and 4% had gestational diabetes. In the years following pregnancy, those with complications related to high blood pressure were 97% more likely to have high blood pressure, and 31% were more likely to have high cholesterol.
Sadiya S. Khan, Lucia C. Petito, Xiaoning Huang, Katharine Harrington, Rebecca B. McNeil, Natalie A. Bello, C.N. Bairey Merz, Eliza C. Miller, Rupa Ravi, Christina Scifres, Janet Catov, Victoria Pemberton, Jasmina Varagic, Phyllis C. Zee, Lynn M. Yee, Mitali Ray, Jin Kyung Kim, Abbi Lane-Cordova, Jennifer Lewey, Lauren H. Theilen, George R. Saade, Philip Greenland, William A. Grobman. Body Mass Index, Adverse Pregnancy Outcomes, and Cardiovascular Disease Risk. Circulation Research, 2023; DOI: 10.1161/CIRCRESAHA.123.322762
Northwestern University. (2023, October 10). Maternal obesity predicts heart disease risk better than pregnancy complications. ScienceDaily. Retrieved October 10, 2023 from www.sciencedaily.com/releases/2023/10/231010105331.htm
Photo by Kei Scampa from Pexels: https://www.pexels.com/photo/hands-of-a-couple-embracing-the-baby-inside-her-growing-belly-3013668/