My due date is oct 2...but when im 9 months ill be sep4th why is that? My 1st pregnancy my due date was july 6 but had baby july 1st only 5 days off.

Dating confusion... The dating of pregnancy can be confusing. Full-term Pregnancy lasts for about 280 days or 40 weeks. If you get out a calendar and count 40 weeks, you will discover that some months (like December) have 5 weeks and some have 4. Saying pregnancy lasts 9 months is an approximation. To be precise, you need to use days or weeks, not months. Still 1 month is quite a difference. Best ask your doc.