Specifications: 

The fetal heart rate is regulated by the sympathetic and parasympathetic nerves. By recording the instantaneous fetal heart rate changes through the curve of the monitoring graph, we can understand the reaction of the fetal heart during fetal movement and uterine contraction, so as to infer whether the fetus is hypoxic in the uterus. In normal pregnancy, fetal heart monitoring is performed once a week from the 37th week of pregnancy. If there are comorbidities or complications, it can be performed from the 28th to 30th week of pregnancy. Attention should be paid to whether the rhythm of the fetal heart sound is fast or slow. The normal fetal heart sound is 110 to 160 beats/minute. If the fetal heart sound is above 160 beats/minute or continuously 100 beats/minute, it indicates fetal hypoxia in the uterus and should be treated in time.

What is the normal fetal heart rate?

Generally, before 15 weeks of pregnancy, there is no need for self-monitoring with an ultrasonic Doppler fetal heart monitor. For pregnant women between 15 and 28 weeks of pregnancy, it is safe to measure 3 times a day for 1 minute each time. For pregnant women after 28 weeks of pregnancy, the fetus is fully differentiated, and the monitoring time and frequency can be extended. For high-risk pregnant women after 35 weeks of pregnancy (for example, pregnant women with pregnancy-induced hypertension, hyperthyroidism, etc.), they should be hospitalized and continuously monitor the fetal heart rate with a fetal heart monitor. If necessary, continuous monitoring can be carried out for a long time (more than 1 hour).

Fetal heart rate is a means of predicting fetal safety, so every pregnant woman needs to keep a record of the fetal heart rate. At this time, pregnant women must know the normal range of fetal heart rate.

1. The normal fetal heart rate is 120~160 beats/minute;

2. The average fetal heart rate before 20 weeks of pregnancy is 162 beats/minute;

3. The average fetal heart rate is 147 beats/minute during 21~30 weeks of pregnancy;

4. The average fetal heart rate is 139 beats/minute during 31~40 weeks of pregnancy.

Abnormal manifestations

In fact, the condition of the pregnant woman herself will also affect the changes in the fetal heart rate. For example, if the pregnant woman has a fever, the fetal heart rate will often exceed 160 beats/minute. If the pregnant woman has hyperthyroidism, her own heart rate is very fast and the fetal heart rate will often exceed 160 beats/minute. If the pregnant woman takes certain medications, it can cause the mother and child's heart rate to accelerate.

A slow fetal heart rate may be caused by fetal hypoxia, but sometimes pregnant women take certain drugs, such as propranolol, which act on the fetus through the placenta, causing the fetal heart rate to slow down. When the fetal heart rate is continuously slow, it is necessary to check whether the fetus has congenital heart disease. In addition, after more than 40 weeks of pregnancy, due to the development of the fetal nervous system, the fetal heart rate may sometimes be lower than 120 beats/minute. Therefore, when there is an abnormal fetal heart rate, it is necessary to carefully analyze the situation, make correct judgments and deal with it. If there is indeed fetal hypoxia, delivery should be carried out as soon as possible.