Maternal obesity stronger predictor of later cardiovascular disease than pregnancy complications

Researchers found that obesity during pregnancy, rather than complications in pregnancy related to obesity, such as pre-eclampsia, better predicts the risk of cardiovascular disease later in life, demonstrating the importance of a healthy weight at this life stage.

Women who are obese before and during pregnancy face an increased risk of cardiovascular disease after pregnancy. In a new study, researchers from Northwestern University in the USA examined how cardiovascular disease risk manifests after pregnancy and found that being obese is a ‘strong indicator’ of increased future risks.

It is hoped that the study, published in Circulation Research, will aid the timing of interventions to reduce these risks of cardiovascular complications later in life for overweight people who are considering getting pregnant.

It is known that being overweight or obese just before or during pregnancy can increase the risk of cardiovascular problems later in life, as well as increasing the likelihood of complications during pregnancy, such as high blood pressure, pre-eclampsia and gestational diabetes. Prior to this research, it was not known whether obesity or the adverse outcomes during pregnancy were the cause of the increased risk of later cardiovascular disease.

The researchers analysed data collected from the nuMoM2b Heart Health Study of more than 4,200 first-time mothers, half of whom were either overweight or obese. Their pregnancy experience was then analysed alongside their heart health between two and seven after they had given birth.

The findings showed that obesity before and during early pregnancy was a strong indicator of future cardiac disease. While adverse pregnancy outcomes were linked to increased cardiovascular disease risk during pregnancy, these complications accounted for a small percentage of the increased risks in the years following for obese women. Complications with high blood pressure explained just 13 per cent of the future risk of high blood pressure if women were obese during pregnancy. In addition, having gestational diabetes during pregnancy only explains ten per cent of the future risk for diabetes.

One of the study authors, Victoria Pemberton, from the Division of Cardiovascular Sciences at the National Heart, Lung, and Blood Institute (NHLBI), said: ‘We’re finding that certain pregnancy complications are unmasking and then increasing cardiovascular disease risks, such as obesity, that were already present.’

For mothers who were overweight or obese in the first trimester of pregnancy, the risk of developing gestational diabetes or having the pregnancy complicated by high blood pressure was double that of people who were a normal weight. The researchers found that being overweight did not affect all pregnancy complications and was found to have no impact on whether a baby was born prematurely or with a low birth rate.

The lead investigator, Professor Sadiya Khan, said: ‘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. That includes achieving and maintaining a healthy body weight, knowing your heart health numbers, and finding ways to stay physically active.

‘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.’