We report and analyze a case of pregnancy associated with pre-existent diabetes mellitus and fetal congenital anomalies involving neural tube defect (NTD) and congenital heart defect (CHD). We discuss the early antenatal management of such high-risk pregnancies. The clinical course, maternal paraclinic profile and morpho-sonographic investigation of the fetus are described. A 28-year-old pregnant woman with pre-existing diabetes and a pre-pregnancy BMI 31 kg/m², without preconception counseling for optimization of glycemic control was evaluated in our center for first trimester genetic screening at 12 weeks of gestation. Considering a high-risk pregnancy, careful fetal morphological assessment by ultrasound was performed; the extensive examination using high-resolution probes, both by transabdominal and transvaginal approach, found hypoplastic left heart syndrome (HLHS) and open spina bifida (OSB). Both anomalies present important difficulties regarding first trimester diagnostic. The couple was informed and chose termination of pregnancy (TOP). We consider that an anomaly scan at 12-13 + 6 gestational weeks by expert operators should be offered to high-risk pregnancies, because it provides the chance to detect the majority of fetal anomalies. This offer for couples the option of an early decision about the management of pregnancy in cases of severe fetal anomalies; postnatal treatment could be discussed as well as TOP and if the latter is chosen, the maternal risk and the potential psychological burden are lowered, as compared with TOP performed in the mid-second trimester.