Ay, normal lang yan, mama! Lalo na kapag heavily pregnant ka, ang stretching movements ay nagre-trigger ng Braxton Hicks contractions, na parang practice contractions lang ng uterus mo kaya may namimilibot na feeling sa tyan. A few of us mums experienced the same thing, especially in the morning pagod pa lang gumising, at honestly nakaka-alarm but it passes within seconds lang. Next check-up mo, mention it to your OB para peace of mind mo, pero most likely okay lang yan, ang katawan mo lang nag-e-exercise, hehe!