The aim of this study is to verify the beneficial effects on insulin resistance and fetal sonographic parameters of a diet supplementation of myoinositol taken during the third trimester by pregnant women affected by gestational diabetes. Participants should be randomly allocated to take either myoinositol or placebo twice/day for 8 weeks. The effect of myoinositol will be checked in blood samples (insulinemia and Homeostasis Model Assessment - Insulin Resistance "HOMA-IR") and in fetal sonographic parameters after 4 and 8 weeks from the beginning of the nutritional supplementation.

Background and Aim:

Gestational diabetes mellitus (GDM) is a carbohydrate intolerance diagnosed during pregnancy that is not clearly an overt diabetes. It is characterized by an increase of the physiological insulin resistance of the pregnancy status. Myo-Inositol is an insulin sensitizing agent that ameliorate the insulin resistance. The investigators have already demonstrated that myoinositol, administered in first half of pregnancy, may reduce insulin resistance and GDM incidence in pregnant women at risk for family history, obesity and overweight . But the experiences in women affected by GDM are few and controversial. So the aim of this study is to test the effectiveness of myoinositol to ameliorate the insulin resistance in GDM patients, diet treated. Moreover the investigators would like to verify the impact of this nutritional supplementation on the fetal sonographic parameters.

Design:

The study is a randomized, prospective, placebo-controlled trial, including the first 80 consecutive gestational diabetes patients diagnosed, according to the Italian Guidelines, from November 2018 to December 2019, in the Department of Obstetric and Gynecology of Messina University (ITALY). After an informed consent participants will be randomly assigned to receive (n. 40) diet and folic acid (400 mcg per day) alone, or (n. 40) diet, folic acid (400 mcg per day) and myo-inositol (2 g. twice a day + 50 mg alfa-lactalbumin) supplementation. Multiple pregnancy or known or suspected fetal congenital abnormality had been previously excluded. The insulin sensitivity index (HOMA-IR) and fetal sonographic profile will be monitor for each patient at GDM diagnosis and after 4 and 8 weeks of treatment. The pregnant women who will delivery before the time treatment (8 weeks) or who need insulin will be excluded.

Inclusion Criteria:

• Singleton pregnancy affected by gestational diabetes

Exclusion Criteria:

• Multiple pregnancy and known or suspected fetal malformations

Placebo administered