Carbohydrates Distribution in Pregnancy Study

Hypothesis: Patients with Gestational Diabetes Mellitus (GDM) have a high risk to develop complications during pregnancy, puerperium and in the newborn. At present there are not scientific evidences about the optimal distribution of meals in the medical nutrition therapy (MNT) and their relationship with glycemic control. Aim: To explore and compare ketonemia and glycemic profile in patients with GDM that follow a MNT distributed in 6 or 3 meals. Besides, we want to explore the differences between both treatments in glucose dynamics. Methods: The study design is a randomized, crossover and multicentric trial. A sample of 10 patients with GDM will be recruited in the Department of Endocrinology and Nutrition from both centres. In a randomized manner patients will follow the conventional treatment (a carbohydrate-controlled diet distributed in 6 meals: 3 main meals and 3 snacks) and the intervention treatment (a carbohydrate-controlled diet distributed in 3 meals: breakfast, lunch and dinner). They will be randomized to begin with one of the two treatments, and after two weeks they will be switched to the other treatment. Patients will wear a blinded continuous glucose monitoring device (iPro2-TM, Medtronic) during the entire study period. Inclusion criteria: * Women with GDM diagnosed in 24-28 weeks. * Age 18-40 years. * Pregnancy age of 28-32 weeks. * Caucasian. * Body mass index ≤ 35 Kg/m2. Exclusion criteria: * Unability to understand the dietary recommendations and/or to perform self-management of glycemia, ketonuria or ketonemia. * A low adherence to MNT. * Problems with written and/or oral communication. * Presence of comorbidities other than obesity, hypertension and dyslipidemia. * Insulin-need criteria within 3 first days of the beginning of the study (fasting glucose ≥90mg/dL, postprandial glucose 1-hour ≥140mg/dL). Clinical and sociodemographic variables will be assessed. Dietary records and blood samples will be collected. Daily basal ketonuria and