I think if she was raped in April, tested in May, it was too early to show a pregnancy. This completely would coincide with the expected dates of delivery in late Jan/early Feb.
Yes, it does. 40 weeks.
Also, if she were not sexually active but was raped, then ended up pregnant, it does not take Einstein to figure who the father was. Of course these days that first condition can be a stretch. Not throwing rocks at her by any means...