The purpose of this study is to determine whether, in Gestational Diabetes Mellitus (GDM) pregnancies, induction of labour at 38-39 weeks of pregnancy is superior to expectant management in terms of maternal and neonatal outcomes.

Gestational Diabetes Mellitus (GDM) is one of the most common complications of pregnancy and its incidence is estimated as around 7%. Babies born from women with GDM are significantly more exposed to perinatal risk. Furthermore in GDM pregnancies an increased C-section rate has been observed, mostly unjustified.

Strong evidence, based on prospective studies and randomized controlled trials, in favour or against the effectiveness and safeness of induction in women with GDM, are missing. The aim of the present study is to identify the best management for these women at term and provide evidence that could change the current clinical practice.

To reach this objective, 1760 eligible women will be recruited at 9 Teaching Hospitals (5 in Italy, 4 all over the world). Sample size has been estimated to demonstrate a difference between the two arms ≥ 6% (31% of C-section in the expectant group and 25% in the induction group; relative difference between the 2 groups equal to 20% in favor of induction; Kjos et al, 1993), considering an α error equal to 5% and 80% power.

Patients will be randomized to induction of labour (N=880) or expectant management (N=880). Data on maternal and neonatal outcomes will be collected at delivery and until maternal and neonatal discharge.

Inclusion Criteria:

• Maternal age > 18;
• Singleton pregnancy in vertex presentation;
• Gestational age between 38-39 weeks verified by LMP and first trimester ultrasound when available;
• Women diagnosed with GDM in the current pregnancy [Diagnosis will be based upon abnormal 50 Gr. GCT (>140) followed by >2 abnormal indices in the OGTT (according to C&C criteria). Women with GCT>200 mg/dl will undergo 100 gr OGTT as well];
• No other contraindications for vaginal delivery.

Exclusion Criteria:

• Pre-gestational diabetes;
• Prior C-section;
• Suspected estimated fetal weight> 4000 gr. at enrollment;
• Any known contraindications for vaginal delivery;
• Uncertain gestational age;
• Non-reassuring fetal status necessitating immediate obstetrical intervention (prompt delivery/prompt C-section);
• Maternal disease complicating pregnancy and necessitating delivery (e.g Severe PET);
• Bishop score >7 at enrollment;
• Major fetal malformation.