My OB never tells me what the heart rate is, I suppose I could ask but I assume it is fine if he doesn't say anything......
Babies heart beats go up and down a lot depending on how active they are at that moment. If your dr says it is fine I would trust her.
A normal fetal heart rate is between 120-180 depending on activity. your baby could have been sleeping.
I guess if your doctor is not concerned, everything is okay.
Incidentally, at my visit today, the midwife said, "150, that's high for a boy." And I thought, Oh? So the "old wives' tales IS true!? Then she said he was moving around, so that made it higher.
I'll bet darkestlight is right, the baby was probably sleeping.
Mine is usually in the high 160's and my last appt it was in the low 130's. Totally normal