Jangan risau sangat, dear, at 10 months (38, 40 weeks), perut keras kat bahagian atas tu is actually quite common, and from what I've heard from mums around me, it's usually Braxton Hicks, which is basically the body's way of "practising" for real labour. These practice contractions can last anywhere from 30 seconds to a couple of minutes and tend to come and go without a regular pattern. However, do keep a closer eye if the hardening becomes very frequent, very regular, or comes with other symptoms like bleeding or severe pain, that would be a reason to head to your doctor sooner rather than later. It is always worth mentioning it at your next check-up or calling your doctor just to be sure, especially since you are so close to your due date. Wishing you a smooth and safe delivery, dear!