Gestational diabetes affects up to 9.2 percent of pregnant women, according to a CDC analysis. If a woman develops gestational diabetes, she is at a much higher risk for developing type 2 diabetes after the pregnancy. Speaking of Diabetes talked to Florence Brown, M.D., Director of the Joslin-Beth Israel Deaconess Diabetes and Pregnancy Program, about the link between gestational diabetes and type 2, and what women can do to prevent the progression from one to the other.
Speaking of Diabetes: What causes gestational diabetes?
Florence Brown: Women who develop gestational diabetes actually have a predisposition that is there even before the pregnancy. They are more insulin resistant and also have less insulin secretion than women who do not end up developing gestational diabetes in their pregnancies. So there’s a metabolic defect that exists before the pregnancy.
Even in normal pregnancy the placenta makes hormones that increase insulin resistance and raise blood sugars. Most women are able to make up for it by making more insulin. But women who already have underlying insulin resistance plus reduced ability to secrete insulin aren’t able to keep up with increasing demands.
That’s why these women are at much higher risk of developing type 2 diabetes in the future. It’s not that the pregnancy is making them develop type 2 diabetes. It’s like a metabolic stress test, so what is already a defect there before the pregnancy is just drawn out. That metabolic defect will still be there after the pregnancy is over and the placenta has been delivered.
SoD: So these women would have had a higher risk for type 2 whether or not they got pregnant?
FB: Yes. You wouldn’t have known they were at metabolic risk if they hadn’t had that pregnancy, but they still would have a higher risk of type 2 diabetes.
SoD: How can women lower their risk for developing gestational diabetes, and then later type 2 diabetes?
FB: Some women who develop gestational diabetes are overweight or obese and weight loss could possibly reduce that risk. And that is theoretical because I don’t believe that there are any randomized, controlled trials to study this. But in general, a healthy lifestyle helps reduce insulin resistance. Any way that you can reduce insulin resistance will help your metabolic profile.
There has been a very large study called the Diabetes Prevention Program (DPP) study that showed with weight loss of about seven percent through healthy diet and regular exercise you can reduce your risk of developing type 2 diabetes by about 50 percent.
That is something we focus on quite a bit in our program. We counsel women that, if they have an elevated BMI, they can reduce their risk of future type 2 diabetes by half if they lose seven percent of their preconception weight once they once they’ve delivered and the pregnancy is over.
SoD: What about women who aren’t overweight before they conceive?
FB: We just we advise them to continue their healthy diet and to exercise, but we do not encourage them to lose weight. We encourage them to get back to what their preconception weight was but the lifestyle aspects can still help those women.
SoD: It seems like gestational diabetes acts as a warning sign for these otherwise healthy women that they are predisposed to metabolic problems, and that they should keep their healthy lifestyles on track?