According to the Centers for Disease Control and Prevention (CDC), an estimated 1 to 14 percent of pregnancies are affected by gestational diabetes. Now, new research has found that maintaining a healthy lifestyle could reduce diagnoses by nearly half.

Gestational diabetes occurs when pregnant women— who did not have diabetes previously— have high blood glucose levels during pregnancy because the body is unable to make and use all the insulin it needs. When this occurs, glucose is unable to leave the blood to convert into energy. Instead, glucose builds up in the blood to high levels. Previous research has shown that women with gestational diabetes have more than a 7-fold increased risk of developing type 2 diabetes 5 to 10 years after delivery.

A study published in the British Medical Journal found that about 48 percent of all pre-existing gestational diabetes pregnancies could have been avoided if the women exercised, maintained a healthy weight and diet and didn’t smoke.

Babies whose mothers suffer from gestational diabetes are more likely to become obese later in life, according to the American Diabetes Association. The disease requires the baby’s pancreas to produce extra insulin, which turns into excess energy that is stored as fat.

In the study, researchers analyzed medical records indicating lifestyle habits and gestational diabetes diagnoses of more than 14,000 healthy women in the United States between 1989 and 2001. Gestational diabetes was reported in 823 pregnancies.

A mathematical formula was used to estimate the proportion of gestational diabetes cases that hypothetically would not have occurred if the women had been in the low-risk group. The low-risk group ate well, maintained a body mass index below 25 before pregnancy, exercised, and did not smoke.

Being overweight or obese before pregnancy was the strongest individual risk factor for gestational diabetes, the study noted. Women with a BMI above 33 had a four times higher risk of developing gestational diabetes, compared to women who had a normal BMI before pregnancy.

In an accompanying editorial, Sara Meltzer, an associate professor at McGill University in Montreal, said that these findings could encourage hopeful mothers to develop healthy habits to improve their pregnancy outcomes.

Making drastic modifications in lifestyle can be challenging, she said, but these conclusions "should give health professionals and women planning a pregnancy the encouragement they need to try even harder.”