A newborn whose mother was poorly controlled diabetic during the third trimester is at risk for what condition?

A newborn whose mother had poorly controlled diabetes during the third trimester is at increased risk for polycythemia. In situations where maternal blood glucose levels are poorly regulated, the fetus may experience elevated levels of insulin and, consequently, increased glucose utilization. This often results in higher red blood cell production as the fetus attempts to adapt to the changes in its environment.

Polycythemia occurs when there is an excess of red blood cells in the newborn, which can be a compensatory mechanism for chronic hypoxia or increased blood viscosity. Given that infants of mothers with diabetes are also at risk for other metabolic disturbances, the increased blood volume and viscosity can lead to complications, including breathing difficulties and increased risk of jaundice.

While hypoglycemia is also a concern for newborns of diabetic mothers, polycythemia is specifically related to the hematologic response of the fetus to the hyperglycemic condition in the mother, making it the more direct risk associated with this context.