Alah tu likely Braxton Hicks je, mama, totally normal at 33 weeks! Perut mengeras sekejap then relax balik, especially kalau banyak gerak or tired. A few of my mum friends experienced the same thing around this time dan takde apa-apa serious pun, alhamdulillah. Since baby aktif normal and you're feeling ok, boleh lah relax, but if the tightening jadi painful, frequent, or disertai spotting, better check with your doctor to be safe, okay?