The study followed 1,133 mothers for an average of almost 15 years, including 139 women with a history of gestational diabetes. None of them had diabetes prior to their pregnancy. They all had periodic glucose tolerance tests that compare blood sugar levels before and after consumption of a sugary drink, to determine if they developed full-blown diabetes or slightly elevated blood sugar known as prediabetes. By the end of the study period, even women with healthy blood sugar levels were 2.3 times more likely to develop coronary artery calcification when they had a history of gestational diabetes. Gestational diabetes also roughly doubled the risk of coronary artery calcification among women with prediabetes, or slightly elevated blood sugar, and women with type 2 diabetes. “Gestational diabetes may reveal underlying metabolic conditions that can worsen over time with aging and weight gain to increase a woman’s long-term cardiovascular health,” says lead study author Erica Gunderson, PhD, MPH, an epidemiologist and senior research scientist at the Kaiser Permanente Northern California Division of Research in Oakland, California. “Even though women with gestational diabetes may later attain normal blood sugar levels, these subtle changes in metabolism may harm the blood vessels and promote the formation of the plaque in her coronary arteries that increases risk of heart disease,” Dr. Gunderson adds. One limitation of the study is that researchers lacked data on pregnancy complications, such as preeclampsia, which can independently influence the future risk of cardiovascular disease. Researchers also didn’t assess how many women with artery disease went on to experience a heart attack or stroke, risks that increase as plaque accumulates in blood vessels. RELATED: Everything You Need to Know About High Blood Pressure During Pregnancy
Gestational Diabetes Also Increases a Woman’s Risk of Heart Attack and Stroke
“Some previous studies have shown that patients with gestational diabetes are at higher risk of heart attacks or stroke even if they were successful in controlling their sugars,” says Tracy Wang, MD, a professor of medicine at Duke University in Durham, North Carolina, who wasn’t involved in the current study. For example, one meta-analysis of 83 studies with a total of almost 29 million patients published in February 2019 in Circulation found gestational diabetes was associated with a 70 percent higher risk of cardiovascular disease. Another meta-analysis of nine studies with a total of roughly 5.4 million women published in March 2019 in Diabetologia found women with a history of gestational diabetes were twice as likely to develop cardiovascular disease. This analysis also found that gestational diabetes was associated with a 56 percent higher risk of events like heart attacks and strokes among women without type 2 diabetes, meaning they had normal or only slightly elevated blood sugar after pregnancy. What the current study shows is that women without any symptoms of artery disease may be at increased risk for plaque buildup in these blood vessels when they have a history of gestational diabetes, Dr. Wang says. “So, we can’t wait until they’ve had a heart attack or stroke, we need to start much, much earlier to control all their risk factors so that we can prevent the heart attack or stroke from happening,” Wang advises.
Pre-Pregnancy Prevention Matters
It’s possible that risk factors present before pregnancy might make women more susceptible to gestational diabetes as well as artery disease and heart attacks down the line, says Ravi Retnakaran, MD, a professor at the University of Toronto and an endocrinologist at Mount Sinai Hospital in Toronto, who wasn’t involved in the current study. A study published in October 2020 in Diabetes Care found that before pregnancy, women who went on to develop gestational diabetes had annual increases in blood sugar almost twice as high as other women. Women with gestational diabetes also had less healthy cholesterol levels before pregnancy. Women can lower their risk of gestational diabetes as well as coronary artery disease by maintaining a healthy weight prior to pregnancy, Dr. Retnakaran advises. “Keeping a healthy weight, and low blood pressure and cholesterol levels, is one way to try to reduce the risk of developing gestational diabetes,” says Wang. “However, some women may be more prone to developing gestational diabetes genetically.”
Reducing Risk After Gestational Diabetes
After pregnancy, women with a history of gestational diabetes should get regular blood sugar tests and adopt lifestyle habits aimed at preventing heart disease and managing type 2 diabetes, Gunderson says. “These women may require more frequent screening and evaluation of established risk factors for atherosclerotic heart disease starting at a younger age, depending on their medical history and their current health factors,” Gunderson notes. Guidelines published in 2019 by the American College of Cardiology and the American Heart Association include these steps to help prevent cardiovascular disease:
Get at least 150 minutes a week of moderate-intensity physical activity or 75 minutes a week of vigorous exercise.Adopt a heart-healthy diet rich in vegetables, nuts, whole grains, lean vegetable or animal protein, and fish.Limit or avoid consumption of red and processed meats, refined carbohydrates, sodas and sugary beverages.Quit smoking.Get evaluated for your 10-year risk of atherosclerotic cardiovascular disease and talk to your doctor about whether you need coronary artery calcium scanning.
“Once a woman does develop gestational diabetes, I would consider treating them as if they had diabetes even if their blood sugars normalize afterward because they are at higher risk for heart attack and stroke,” says Wang. “Not only do I keep a close eye on their blood sugars, I also ask my patients to exercise at least five days a week, restrict cholesterol and fat intake in their diet, and maintain a healthy weight.”
