Didn't get to that situation during our application but I did my research, in case.
Did your spouse do her medical exam yet? If not, she will still be doing it but x-ray will probably be postponed until she gives birth. If she has done it but will give birth before coming to Canada, this will delay your application because you will then also have to add the baby to the application.
If she has done her medical exam and she will give birth after getting here to Canada, that's the most optimal situation. Just be aware that if she hasn't met the province's health insurance criteria (some require that newcomers must be in that province for a couple months before being eligible), then you will have to foot the hospital bill, unless you can get private health insurance.