Gestational diabetes had been connected to cardiovascular disease prior to this study, but little was known of the links between minor glucose intolerance and heart disease. Type 2 diabetes and cardiovascular disease share several characteristics including obesity, insulin resistance and cholesterol problems. Oftentimes, individuals with one condition will develop the other. Women with gestational diabetes may experience similar metabolic complications as soon as 3 months after giving birth.

Researchers analyzed the medical records of all Ontario women between the ages of 20 and 49 who had given birth between April 1994 and March 1998.  Participants were divided into three groups: those who were diagnosed with gestational diabetes, those who received an oral glucose tolerance test, and those who were not screened using oral glucose testing. One birth was selected at random for women with multiple deliveries; the median ages were between 29.2 and 31.1.

Women are tested for gestational diabetes (a type of diabetes that develops when women experience unusually high glucose levels during pregnancy) during the second trimester of pregnancy (13-27 weeks). The first step is a glucose challenge test, taken by measuring glucose levels one hour after ingesting a sugary substance such as glucola. If results are abnormal (≥7.8 mmol/L), a second oral glucose tolerance test (OGGT) is taken.

Participants in the study were followed up until March 31, 2008, providing information reflecting cardiovascular disease development for a median of 12.3 years after childbirth. “If you followed 10,000 people for one year, 4.2 of them would have an event,” Dr. Shah explains. “If you followed those 10,000 people for 10 years, 42 of them would have an event…In other words, these are extremely rare events.”

Although the differences were minor—absolute risk was 0.16% and 0.05% for women with gestational diabetes and women who received an OGGT, respectively—the results indicate a need for further research. "We shouldn't be ignoring these mild abnormalities during pregnancy,” Dr. Shah says. “(They) may benefit from extra surveillance and/or cardiovascular disease screening.”

More information is needed to establish the exact relationship between glucose intolerance and cardiovascular disease. In the meantime, proper nutrition and exercise may reduce your risk for both gestational diabetes and cardiovascular disease.

Read more about gestational diabetes and cardiovascular disease.