No fetal movement at 12 week ultrasound but strong heartbeat. should i worry?

Dont think so.: I'm not in MFM (Maternal / Fetal Medicine) nor an Obstetrician, but I know my wife's OB told us not to worry in similar circumstances with my daughter (who is now 2.5 years old). Babies (fetuses) sleep at odd times & can sleep right through an ultrasound, so lack of movement is not worrisome per se. The heart rate is reassuring. Talk to your OB & make sure repeat ultrasound is scheduled. Good luck