A failing strategy? Gestational diabetes risk not lowered through reduced weight gain research finds

15 Jan 2019 --- Conventional ways to prevent gestational diabetes mellitus are ineffective and its appearance possibly depends on each individual’s health, according to a recent Pennington Biomedical study. The results found that moms-to-be who ate healthier and less, and increased their physical activity, developed gestational diabetes at about the same rates as women who didn't follow the same lifestyle. The researchers now believe there may be different types of gestational diabetes that warrant different approaches to treatment and prevention.

“It was surprising to learn that for women with obesity, lifestyle-related factors attributing to early weight gain, such as diet and exercise were not different between women who developed gestational diabetes and those who did not,” co-author of the study, Leanne Redman, Director of LSU Pennington Biomedical Research Center, tells NutritionInsight.

“Gestational diabetes is thought to be similar to Type 2 diabetes in that lifestyle factors such as low levels of physical activity and a poor quality diet with high amounts of added sugar are linked to its development. As such, lifestyle change is considered the superior approach for prevention and treatment of gestational diabetes like Type 2 diabetes alike,” she adds.

Gestational diabetes leads to health issues for the mother and child, issues which can extend well beyond pregnancy. Around 50 percent of women with gestational diabetes go on to develop Type 2 diabetes, according to the federal Centers for Disease Control. Babies exposed to gestational diabetes have higher chances of developing Type 2 diabetes and a higher risk of being overweight or obese.

The researchers found that in pregnancy, energy balance may not determine the development of gestational diabetes. This has led the researchers to believe that there are different types of gestational diabetes that warrant different approaches to treatment and prevention.

The new study is the latest evidence that the “first-line” strategy for preventing gestational diabetes mellitus isn't working. Over the past five years, more than 5,000 pregnant women took part in clinical trials that focused on limiting weight gain in order to prevent gestational diabetes.

“Preventing gestational diabetes is not as simple as reducing weight gain,” says Jasper Most, Ph.D., co-lead author of the study. “It may require more individualized approaches based on each person's risk factors.”

According to Dr. Most, some women may develop gestational diabetes because their pancreas doesn't adequately adapt to producing additional insulin to match the increased demand of pregnancy. Others may develop gestational diabetes because their muscles and livers become more insulin resistant.

The study spanned five years and followed 62 obese pregnant women, nine of which developed gestational diabetes. 

The research found that:

• The primary risk factors for gestational diabetes, such as excess fat and insulin resistance, were evident early in pregnancy.
• Women who developed gestational diabetes tended to be heavier. They weighed 10-35 pounds more. They also had more body fat, from 7-25 pounds, and significantly more fat around their waists.
• The women also had more relatives with diabetes, significantly higher fasting blood sugar levels and a greater prevalence of prediabetes. 

The researchers do not suggest that women abandon healthy lifestyles, but that maybe they don’t play such a significant role in the development of the affliction. 

“The results do underscore the need to better understand the way that gestational diabetes develops in women with obesity,” Dr. Redman says.

Classical Type 2 diabetes risk factors such as higher blood sugar, glycosylated hemoglobin A1c levels and insulin resistance are pinpointed as early indicators of gestational diabetes management, according to the study. 

“Clinical practice would be advanced by earlier evaluation of such risk factors in patients considered to be at high-risk such as those with obesity prior to pregnancy,” adds Dr. Redman.

“The study also emphasizes the importance for women in higher risk groups to optimize health prior to conception to maximize healthy outcomes during pregnancy,” she adds.

 More research is needed to evaluate other factors that lead to gestational diabetes and insulin resistance in early pregnancy.

“What we want to do now is enroll women in a new study that has different types of gestational diabetes,” Dr, Redman tells NutritionInsight.

 “So women who might have insulin resistance or women who might have impaired insulin secretion would be studied to see which ones would be more receptive to a lifestyles program versus another kind of treatment,” she concludes.

By Laxmi Haigh and Kristiana Lalou