A normal fetal heart rate (FHR) usually ranges from 120 to 160 beats per minute (bpm) in the in utero period.It is measurable sonographically from around 6 weeks and the normal range varies during gestation, increasing to around 170 bpm at 10 weeks and decreasing from then to around 130 bpm at term. normal fetal heart rate (FHR) usually ranges from 120 to 160 beats per minute (bpm) in the in utero period.