Low Fetal Heart Rate at 8 Weeks Question

I am 8 weeks pregnant and had some spotting at 6 weeks.  I had an ultrasound and everything looked good.  The baby's heart rate was at 114 and all looked well.  I had some more spotting at 7.5 weeks and went in to have another ultrasound.  The baby's heart rate was down to 77 and my doctor was concerned.  The doc has me waiting another week for an ultrasound but I am worried and concerned about the baby.  Has this every been seen in an early pregnancy and has a woman had a healthy baby after this.

[lawgirl17]

I know that my OB will not monitor heart rates until around 18 weeks because the child moves around so much in the uterus that the heartrate is constantly changing, and they don't want to unduly freak anyone out. Hopefully the only reason the baby's heartbeat was so low when you went in was because he was sleeping or something as opposed to having a higher rate from activity. I wish you the best. Please let us know how your f/u goes.

[Jazzers07]

I am 6 weeks 6 days pregnant (through IVF) and had my first ultrasound today.  I spotted a bit last week so they moved my scan up a few days from where they normally would have done it.  There were two gestational sacs.  The first had a normal looking yolk sac and measured exactly 6 weeks 6 days and we were able to see and hear the heart beat.  Dr. said it was 115 bpm which was a tad low but said not to worry since it was a bit early.  The second sac had something in it and showed "some" movement but Dr. would not confirm it was a heart beat.  It measured only 5 weeks 4 days so I am obviously concerned.  I know I should be thrilled that one seems to be developing normally but with the slightly low heartbeat and not sure what's going on with the second one, I am a wreck!  Anyone else out there had a low heart rate that turned around and came back stronger?  What about a twin that seemed to be developing slower?