He might not have as much room to move as much.
I agree with he first comment. I was 39+1 with my daughter and has my membranes swept. But had to go to the ER after my appointment because she wasn't moving and my blood pressure wasn't normal. Once I got hooked up she moved a little bit and not to long after that my water broke. But still get checked out. Good luck :)
Id go get checked out just in case but most babies movement become a little less with the lack of room in their little home. I wouldnt worry but i would just ge checked out for babys safety :)
I heard a decrease in movement is a sign of labor. But call your doctor and do kick counts if your woried