Fetal heart rate in the first and second trimester | 合法醫療器材資訊網

Anormalfetalheartrate(FHR)usuallyrangesfrom120to160beatsperminute(​bpm)intheinuteroperiod.Itismeasurablesonographicallyfromaround6 ...

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.

Although the myocardium begins to contract rhythmically by 3 weeks after conception (from spontaneously depolarizing myocardial pacemaker cells in the embryonic heart) it is first visible on sonography around 6 weeks of gestation. The FHR is then usually around 100 to 120 beats per minute (bpm).

FHR then increases progressively over the subsequent 2-3 weeks becoming 7:

This is followed by a decrease in FHR becoming on average: