I'm going to suggest that you go to Insuremytrip, put in your parameters, and read everything very carefully. Also check your own health insurance for coverage abroad.
You should know how many weeks pregnant she will be as you return. There may be some sort of cut off.
I found this page from Allianz regarding coverage from their products:
https://www.allianztravelinsurance.c...-insurance.htm
I traveled at roughly that much pregnant when young and didn't even think about coverage. You're smart to be looking into this.