One in five pregnant women has obesity in Europe. It is an independent risk factor for maternal and foetal complications during pregnancy and delivery, increasing linearly with pre-conceptional body mass index. Excessive gestational weight gain further aggravates these risks. The clinician should measure body weight at each visit from the 1st trimester of pregnancy, search and monitor complications and be aware of preventive measures. A balanced diet with low glycemic load and light to moderate physical activity 30‑60 minutes 3‑5 times per week should be recommended during pregnancy and postpartum to control gestational weight gain and reduce the risks of short and long-term maternal and infant complications.