I am currently 16 weeks pregnant and a larger woman. I have had 2 previous miscarriages. First at 19 weeks and second at 7 weeks. I eard the heartbeat at 12 weeks and also had an ultrasound at 14 weeks and everything looks ok. I went to the doctor's yesterday for my 16 weeks checkup and he was concerned because I gained 8 lbs over the month and he could not detect the fetal heartbeat. He told me not to worry because he could have low battery's in the doppler or it could be the weight that's getting in the way. He told me not to worry about it and booked me in for another ultrasound in 2 weeks to see if things are ok. I'm not sure if I can wait that long. Has anyone else had this happen before?