I was at the end of my second trimester, and the nurse filled a disposable cup with 50 grams of glucose powder – a tad less than the amount of sugar in a 16-ounce bottle of Coke – and sent me to the water fountain to dilute it.
I dutifully drank the sugary concoction that constituted the first part of the glucose screening test, a routine procedure used to help determine whether pregnant women have gestational diabetes mellitus, glucose intolerance that first becomes apparent during pregnancy. As I waited the required one hour until the nurse could draw my blood, I wasn’t particularly concerned. After all, I figured, even if I did have gestational diabetes, all it meant was a few months of careful eating and then the condition would disappear by the time I got to meet my baby.
I ended up being lucky enough to pass the glucose test in all my pregnancies, but as for the assumptions I made – well, they may have been commonplace, but it turns out they weren’t completely accurate. That’s because while gestational diabetes, which affects an estimated 5 percent to 9 percent of pregnancies, does disappear with delivery, it also leaves something behind: an elevated risk of type 2 diabetes and heart disease for the mother.
“A woman with a history of gestational diabetes has a very high risk of developing diabetes later in life, even if their sugar goes back to normal after pregnancy, and that puts them at increased cardiovascular disease risk,” said Dr. Erin Michos, the associate director of preventive cardiology at the Johns Hopkins Ciccarone Center for the Prevention of Heart Disease, and an associate professor of medicine at Johns Hopkins University. “Many women have no idea that this is a cardiovascular disease risk.”
Gestational diabetes is more prevalent than it was in the 1990s, and the increasing numbers of women who exhibit glucose intolerance when pregnant have more than seven times the risk of developing type 2 diabetes by the time that child is 10, compared with women who didn’t have gestational diabetes.
Another way of putting it is that between 35 percent and 60 percent of women who have had gestational diabetes develop type 2 diabetes within a decade of delivery.
Those women with gestational diabetes who go on to develop type 2 are not necessarily the only ones who have to worry about heart disease, though.
There have been mixed findings as to whether gestational diabetes is an independent risk factor for heart disease or contributes to elevated risk because of other factors, such as obesity and the onset of type 2 diabetes.
Researchers at Soroka Medical Center in Israel are among those who found gestational diabetes to be a risk factor for heart disease in its own right. They based their conclusions on a large study of 47,909 deliveries at the hospital, published in the journal Heart in 2013, that followed patients for more than a decade and compared the cardiovascular complications and related hospitalizations of the 10 percent of women in the study who had gestational diabetes with the rest of the women who gave birth during the same period.
And a 2014 study in the Journal of the American Heart Association looked at 898 women between the ages of 18 and 30 and found that the artery walls of those with gestational diabetes were thicker, a measurement sometimes used as a proxy for cardiovascular disease.
“Our research shows that just having a history of gestational diabetes elevates a woman’s risk of developing early atherosclerosis,” epidemiologist and study lead author Erica Gunderson, a researcher at Kaiser Permanente Northern California, said in a statement. “Pregnancy has been under-recognized as an important time period that can signal a woman’s greater risk for future heart disease. This signal is revealed by gestational diabetes.”
So what does this link connecting gestational diabetes, type 2 diabetes and heart disease mean for women who have had glucose intolerance during pregnancy?
Medical experts like Michos and Dr. Ellen Wells Seely, a Harvard Medical School professor who heads the clinical research, endocrinology, diabetes and hypertension division at Brigham and Women’s Hospital in Boston, focus on the need for increased awareness of that connection – among doctors as well as patients.
They suggest that women who have had pregnancy complications such as gestational diabetes or preeclampsia should tell their doctors about it, get regular glucose screening tests, and institute lifestyle changes like eating healthier and exercising more.
Indeed, the American Heart Association issued guidelines in 2011 instructing health care professionals to take a history of pregnancy complications. The guidelines note this is particularly important because heart disease is the leading cause of death in women in every major developed country and most emerging economies, and death rates for coronary heart disease among U.S. women aged 35-54 appear to be on the rise.
Yet doctors may too readily dismiss women’s complaints of potential cardiac symptoms because they don’t match the classic profile of how a heart attack patient looks and feels, said Seely.
Take a woman who shows up at a hospital or health clinic with chest pressure. “If she’s a young, otherwise healthy woman, people might say, ‘Oh, it’s esophageal reflex,’ and send her home,” said Seely.
“Clinically, we’re really trying to get out the word that caregivers need to get a pregnancy history,” she said, adding that doctors need to “consider these pregnancy complications as risk factors for heart disease.”
Michos said she encourages patients to discuss their pregnancy histories with their doctors. She recommends that women who had gestational diabetes get their sugar levels measured in the first year after birth, and at least every three years after that.
“The baby comes, they’re busy being a mom, and they don’t realize they’re at risk,” said Michos. “Many women are being caretakers for other people and they don’t prioritize their own heart health.”