Final answer:
The nurse should advise the woman to switch to insulin for better control during pregnancy as oral hypoglycemics have not been proven to be safe during pregnancy.
Step-by-step explanation:
The nurse should respond to the woman on Orinase (oral hypoglycemic) that it's advisable to switch to insulin for better control during pregnancy. This is because oral hypoglycemics, such as Orinase, have not been proven to be safe during pregnancy and may pose risks to both the woman and the developing baby. Insulin, on the other hand, is considered the standard treatment for gestational diabetes and offers more precise control over blood sugar levels.