Your female needs good quality puppy food.
Puppy food has higher protein and fat content.
It also has calcium which is important when she is nursing. Of course she should have started puppy food in her first few weeks of her pregnancy. If she is a finicky eater, discuss with your Vet the proper dosage of Vitamins and calcium content that her body requires according to her wight. Note I recommend just under the recommend dose. To much calcium can cause Eclampsia.