Hey mama! Alam ko yan na worry, ako din nag-alala dito before, pero at 15 weeks pa lang yan, most of the time the placenta moves up pa as your uterus grows, so don't stress too much yet. Best to talk with your OB about this sa next checkup, they'll monitor it and let you know what to do, usually they just watch and recheck sa later ultrasounds kaya seryoso lang talaga ang follow-ups. A few of us mums na naka-experience nito, after repeat scans lang naging normal positioning na, so marami pang mangyari pa until labor, pero seryoso lang talaga ang pag-attend ng appointments para sure. Praying for you na okay lang lahat!