Fetal Heart Rate 13 Weeks: Understanding Fluctuations & What to Expect

Question
I am 31 years old. gravida 4  para 2  1 missed abortion.  12 2/7 weeks by dates and 13 weeks pregnant by sono 1/27/05.  Fetal heart rate in the 90's by sono and 110 in office the same day.  No signs of threatened abortion.  No cramping or bleeding.  Scheduled for 2nd sono in 4 weeks.  How worried should I be about the low heart rate?

Answer
At this stage of pregnancy, it is common to have severe fluctuations of fetal heart rate. If you have no signs of bleeding, your cervix is closed, and there is adequate growth of the fetus, I would not worry at this point. The normal heartrate of a fetus is 120-160 beats/min. However, that is the average and it can fluctuate from 110-170 with no problems. If it goes below 100, I would merely be observant. There is nothing else you can do at this time.