It's later in the interview; searching on "wife" gets you right to it.
I had actually heard this story about the Santorums before, in a context in which purportedly liberal people were freaking out that they had brought the body home and went through a mourning process. I was somewhat offended that anyone would mock an approach that struck me as sensitive and respectful of the shock associated with a late miscarriage/perinatal death. It is not helpful to a family to sort of pretend it didn't happen. There are a lot of ways to deal with this shock and the one chosen by the Santorums deserves respect.
Unlike their politics.