Ps good on you for coming here to get some advice and reassure your wife. What a lovely husband.
You might like to buy your wife a book called Birth - it's written by an Australian midwife and I think it's really good (and I've read a few of these books now as an obsessive IVF'er).
You can get it in hardcopy or on the e-book store.
I suggest this because in pregnancy Dr Google is not always helpful and can just increase your anxiety so it's better to read legitimate, referenced and published stuff.
Good luck with the pregnancy