Back from first U/S....nervous!

APrice

I posted last night that we had our first U/S today....so we go into the ultrasound room and all looked great according to the u/s tech. She said everything (gestational sac, yolk sac, and fetal pole) was measuring as it should according to my LMP...she thought she was able to get some faint cardiac activity, which is more than we expected.Then we go and meet with the OB and said says that the heart rate was very slow for how many weeks I am. The u/s tech noted that the heart rate was 75 BPM...so now I'm confused and I ask what the heart rate should be and she says that they like to see it between 125-175 BPM....now I'm worried!?! I wasn't even expecting to hear any heart beat yet and now my OB says it is slow....what gives?? Any advice or thoughts??