Just tested and works fine for me. Are you going by the stats menu or the debug menu? Because the stats menu wont update until Sammy has a test or her belly starts to really grow.
I think it was the debug menu. Becouse I had a problem - increasing fitness didn't work. After that I went to the script and found that only the pregnant option limit the body state. And even if increase fitnes to 100, Sammy is still fat. It's looks like I missclick "Advanced pregnant" before. Impregnante didn't fix the problem, only a few clicks on "Advanced pregnant" became to childbirth, and after that increasing of fitnes starts work.
Any way, the game is great! Thank you!