The fetal heartbeat (i.e., fetal heart sound) is normally 110 to 160 beats/minute, and a fetal heartbeat of 155 at 20 weeks of pregnancy falls within the normal range. Fetal heart rate during pregnancy is normally 110 to 160 beats/minute, if it is more than 160 beats/minute it is fetal tachycardia, and less than 110 beats/minute is fetal bradycardia. Fetal heart rate may increase after fetal movement, which is normal. Occasional increases or decreases are transient and should not be a cause for concern as long as they quickly return to normal. If the fetal heartbeat continues to increase or decrease, it is abnormal and may be related to intrauterine oxygen deprivation, and prompt medical attention is needed.