Oo naman, normal yan! Around 15 weeks, ang uterus mo ay lumalaki na talaga kaya parang may tensioning or hardening ka, lalo na pag nag-stretch ang muscles mo or nag-move ka ng biglaan, a few of us first-time moms din nag-panic sa simula hehe. But if it's happening frequently, nag-hurt kang masakit, or may spotting or unusual discharge, please check with your OB agad para peace of mind mo lang, kasi better safe than sorry talaga with pregnancy.