Do you give them
timothy hay? It is a very important part of the diet.
If she is pregnant you need to make sure she has her own cage and not let them out for play time together. He will breed with her again as soon as she has had the babies, if he is allowed to and also if in the same cage will most likely kill the babies, or she will kill them due to the stress of having him in the same cage.
Do you know the day they bred? If that is day 1, you should have babies on day 32. We would usually put a nestbox with hay in the cage on day 28.