Oo, normal yan sa pregnancy, lalo na paglaki ng baby! Ang mga Braxton Hicks contractions (practice contractions) ay pwedeng magsimula kahit early pregnancy pa lang, pero sa 15 weeks mas likely pa yan ay muscle tightening or ligament stretching lang habang lumalaki ang uterus. A few of us mums noticed the same thing, especially when we were tired or active, pero sabi ng doctors namin normal lang talaga, just make sure your wife drinks plenty of water, takes it easy, and let her know na she can always ask her OB about it next visit kung worried sya, just para peace of mind lang.