Fetal Movement

Hi mamas! I'm currently 29+3 and while my baby is moving, the kicking vs hiccups and moving of his arms has decreased over the past day or so. It's been almost 8 years since my last pregnancy and so it's been a while for me. I know space is limited in there (I'm measuring at 31 weeks) and that the intensity behind the movements won't be as strong, I'm just curious as to what's going on in there! Have any other mom's experienced this (a decrease in leg movement from baby)?