Understanding Early Fetal Heart Rates: A Patient's Concern

Question
Hello,

I am 42 years old and pregnant using donor sperm and an IUI on Sunday Nov. 13th (it was CD23 so 9 days past the average of CD 14). Last week I had an ultrasound when I was 6w5d. The embryo was visible but only measured 6w2d but my doctor says this figure is +/- 5 days so therefore acceptable. My biggest concern is that the heart rate was 101 bpm. I feel this was very low but my doctor acted like it was fine and average. Everything I have read on the internet says that from 6.5 - 7 weeks that a hb of less than 120 is low and gives a prognosis of only about a 61% chance of survival. Was my doctor not really being straight with me or just overly optimistic or is a hb of 101 at 6w5d really quite common? I just want an honest answer about the chances of this pregnancy proceeding normally whether it's good news or not. Thank you, suzanne

Answer
Although the normal fetal heartrate ranges between 120-160bbm, there is no reason to be alarmed at a rate of 101 at this stage of pregnancy. There are fluctuatiohs of heartbeats due to changes in umbilical artery blood flow and other physiologic changes. Unless there is a persistent and worsening bradycardia, I would not worry.If the pregnancy is not viable, there will be other manifestations that will come to light.