When your female is expecting there are many things you will want to do to keep her healthy, safe, & happy.
This is a rather short stage of the breeding process. They only are pregnant for about 36 days. So you have little time to prepare her, her cage, & yourself for the new additions.
When you first start breeding her is really when you want to start giving her extra care. I personally dont let her have the wheel to run in as they will run run & run some more which i wouldnt think would be too good for a creature carrying possibly 6 babies in them. For more safety i would remove any tubes that she could get stuck in with a widening waste line.
As for food, i still feed a high quality cat food with a low fat content as well as lots of protein. On top of that i make sure to feed a nice variety of fruits, veggies, cooked eggs, cook/unseasoned meat,yogurts & of course a treat here & there.
Still let your hog out for play time as she does need the exercise & still needs time to explore. (Dont let her out to play 2 weeks before she is expected to give birth though.)
Other than keeping her happy, safe, & healthy, be sure to give her a lot of love, but at the same time be sure to give her all the space she needs.
Many hogs become antisocial when they are expecting & or have the hoglets, but you cant really blame them now can you? hehe.
Most times this does go away & they become friendly again, but there are hogs that can never be a pet again after being bred to due stress & other reasons.. Please take that into consideration.