Previous studies have shown that inositol supplements may help restore fertility in polycystic ovary syndrome, but this is the first evidence that the supplement called myo-inositol may reduce the number of cases of gestational diabetes. Women who are overweight or obese or have a family history of diabetes are at risk for gestational diabetes.

Lead author, Dr. Rosario D'Anna and colleagues of the Department of Obstetrics at University Hospital in Messina, Italy selected 220 pregnant women with a family history of type 2 diabetes. Half the women were given two grams of myo-inositol supplements twice a day along with the recommended amount of folic acid, a supplement recommended for all pregnant women. The compound is also found in fruits, nuts, grains, and meats, but not at very high levels.The other women were given only folic acid, from the end of the first trimester throughout pregnancy.

Of the women who took myo-inositol, six percent developed gestational diabetes, compared to 15 percent of the women who only took folic acid, according to the study

None of the babies in the myo-inositol group met criteria for being overweight, but seven babies in the non-supplement group did, weighing more than eight pounds, 13 ounces.