Gestational diabetes mellitus (GDM) is a common disorder of glucose metabolism that is detected for the first time in pregnancy; its global prevalence is estimated to be 15.8%. The main risk factors for the disease are overweight and obesity (body mass index, BMI 25–29.9 kg/m2 and ≥30 kg/m2), and in Finland in 2021, almost 40% of pregnant women were with overweight . GDM predisposes women to complications for both mother and child, including preeclampsia, complications at delivery, inclusive of the need for caesarean section, shoulder dystocia, physical birth trauma and admission to the neonatal intensive care unit, and later in life to an increased risk for type 2 diabetes.