Glutaric aciduria type II (GA II) is a genetic disorder that interferes with the body's ability to break down proteins and fats to produce energy. Signs and symptoms vary greatly depending on the age of onset and severity of the condition. Pregnancy may be a high-risk period in women affected by metabolic disorders, because the mother must guarantee wellness for both her and fetus. A 37-year-old primigravida woman affected by a mild form of GA II presented to our high-risk department. During pregnancy a dietician strictly controlled her diet and nutritional intake. The fetal growth was regular but around the 38th week a polyhydramnios was diagnosed. A modification in carbohydrate intake led to a normal amniotic fluid. Considering the high risk of metabolic decompensation during labor, an elective cesarean section was programmed. The rare disease geneticist gave some indications to follow before, during and after delivery to reduce the risk for the mother. No complications occurred and the patient with her baby was discharged on the third postoperative day. We present a case report and a review of literature. In pregnant women affected by GA II periodical nutritional and obstetrical evaluations are important to monitor maternal condition and fetal growth. Adequate nutrient intake is fundamental to preserve mother and fetus from complications. Elective caesarean section is preferred to reduce metabolic distress during delivery and to avoid the risk of metabolic crisis. Pregnant women with metabolic diseases are increasing, consequently guidelines may be necessary for a better management.