Could be any number of reasons why Maryse disappeared after the announcement. She may not have been under contract (and if she was, she certainly was not full-time like Maria), and the Miz certainly didn't need her to advance his then-storylines. That's not counting that it could have been Maryse's choice not to go on the road while preggo. On top of that, how much extra work was she doing with the Miz & Mrs. filming? It's not like she was a fixture before getting pregnant.
It's not exactly much of a risk for Maria to do some backstage segments and berate her husband on a weekly basis at 13 weeks. She's pregnant, not an invalid.