Pregnancy complications increase and unmask short- and long-term cardiovascular risk for people with obesity

Having obesity before and during early pregnancy appears to be a strong indicator of risk for developing future cardiovascular disease and was significantly linked with adverse outcomes during pregnancy such as high blood pressure, preeclampsia, and gestational diabetes, according to a study published in Circulation Research that was funded by the National Institutes of Health. Researchers have known obesity is a risk factor for cardiovascular disease and pregnancy complications related to blood pressure. However, they did not know which factors—obesity or the pregnancy complications—played larger roles in influencing a person's cardiovascular disease risk years after pregnancy.

While having adverse pregnancy outcomes was linked with increased cardiovascular disease risks during pregnancy, the complications accounted for a small percentage of increased cardiovascular disease risks in the years following pregnancy for people with obesity.

"We're finding that certain pregnancy complications are unmasking and then increasing cardiovascular disease risks, such as obesity, that were already present. This study provides insight into potential timing for interventions for people with overweight or obesity who are thinking about pregnancy," said Victoria L. Pemberton, R.N.C., a study author and researcher in the Division of Cardiovascular Sciences at the National Heart, Lung, and Blood Institute (NHLBI), part of NIH.

The researchers analyzed data collected from the nuMoM2b Heart Health Study of more than 4,200 first-time mothers—about half of whom had overweight or obesity. They compared the participants' pregnancy experience to their health two to seven years later. They found mothers who were overweight or had obesity during the first trimester of pregnancy had about twice the risk for developing gestational diabetes or having a pregnancy complicated by high blood pressure, compared to participants with a normal body weight. These mothers also had increased risks for developing cardiovascular disease risks after pregnancy.

In comparison, pregnancies complicated by high blood pressure explained just 13% of future risks for developing high blood pressure if a person had obesity. Likewise, gestational diabetes explained only 10% of future risks for diabetes.

"We want to do everything we can to support a person's heart health, but especially around the time of pregnancy—before, during, and in early pregnancy," said Sadiya S. Khan, M.D., the study's lead investigator, a preventive cardiologist, and an associate professor of medicine at Northwestern University Feinberg School of Medicine, Chicago. "That includes achieving and maintaining a healthy body weight, knowing your heart health numbers, and finding ways to stay physically active."

For some complications the researchers found body weight did not factor into risks. For example, people with overweight or obesity did not have increased risks for having a preterm birth or a baby with a low birthweight. Additionally, researchers found among all participants, those experiencing preterm births had increased risks for having high blood pressure, high blood sugar, or high cholesterol a few years after pregnancy. Having a baby born with a low birthweight wasn't found to increase risks.

"Looking for ways to support and optimize a person's cardiovascular health is still of the utmost importance if someone has had an adverse pregnancy outcome," said Khan. "However, if we really want to make a difference in improving cardiovascular health and preventing these pregnancy outcomes, we have to shift to the pre-pregnancy and early pregnancy space."

More information:
Adverse Pregnancy Outcomes, and Cardiovascular Disease Risk, Circulation (2023). DOI: 10.1161/CIRCRESAHA.123.322762

Provided by NIH/National Heart, Lung and Blood Institute