Final answer:
Poorly controlled maternal gestational diabetes can produce fetal hypoglycemia.
Step-by-step explanation:
The best response by the nurse to the client with poorly controlled gestational diabetes is that it can produce fetal hypoglycemia. Gestational diabetes occurs when there is high blood sugar during pregnancy, which can increase the risk of complications for both the mother and the baby. Poorly controlled maternal gestational diabetes can affect the fetus by causing their blood sugar levels to drop too low, resulting in fetal hypoglycemia. It is important for the client to work with their healthcare provider to manage their blood sugar levels to minimize the effects on the fetus.