Gestational Treatment With Ursodeoxycholic Acid Compared to Placebo to Reduce Severity of Gestational Diabetes Mellitus Diagnosed at 24-28 Weeks' Gestation

Inclusion Criteria: * Women with GDM diagnosed at 24-28 weeks' gestation in accordance with Spanish guidelines in accordance with NDDG criteria, i.e. two or more glucose concentrations (fasting: ≥ 5.8 mmol/L (105 mg/dL), 1 h: ≥10.6 mmol/L, (190 mg/dL) 2 h: ≥9.2 mmol/L (165 mg/dL), 3 h: ≥ 8.1 mmol/L (145 mg/dL)) after a standard 100g OGTT, two fasting blood glucose levels ≥ 126 mg/dl, on different days, or at random ≥ 200 mg/dL or a plasma glucose value greater than 200 mg/dL after OSullivan test * Planned antenatal care at the same centre (i.e. not planning to move before delivery). * Singleton pregnancy. * Informed and written consent. Exclusion Criteria: * Age \<18 years; * Multiple pregnancy in current pregnancy; * Unconscious or very ill; * Serious mental illness; * Learning difficulties; * Not fluent in local language and absence of interpreter. * Severe congenital anomaly on ultrasound * Previous diagnosis of diabetes outside of pregnancy * Significant pre-pregnancy comorbidities that increase risk in pregnancy, for example renal failure, severe liver disease, transplantation, cardiac failure, psychiatric conditions requiring in-patient admission (\<1 year) * Significant co-morbidity in the current pregnancy, nephropathy (estimated GF\<60ml/min), other physical or psychological conditions likely to interfere with the conduct of the study and/or interpretation of the trial results * Participating in another intervention study that will influence the outcome of this trial (to be advised by CI or PI). * Known allergy/hypersensitivity/intolerance to the active substance or excipients. * Hypersensitivity to Ursodexosolic acid or to the following excipients: Magnesium stearate, cellulose powder, colloidal silica and sodium carboxymethyl starch, gelatin, titanium dioxide, quinoline yellow, orange yellow S, indigotine. * Patients with a non-functioning gallbladder, in patients with calcified cholesterol stones, radio-opaque stones, radiolucent gallbladder stones. * Gastric or duodenal ulcer. * Liver or intestinal disorders that interfere with the enterohepatic circulation: acute cholecystitis that does not subside, cholangitis, biliary obstruction, pancreatitis due to stones, patients with gastrointestinal-biliary fistula. * Breastfeeding