To answer this question, we must first understand the working principle of fetal heart rate.
The traditional fetal heart rate monitor on the market uses Doppler ultrasound technology, that is, through the characteristics of ultrasound (directivity, reflection, attenuation, resolution, penetration, etc.), it transmits and receives its echo signals to the fetus for inspection. Sound waves are a physical factor, an energy, and there is a question of a safe dose. Therefore, the traditional fetal heart rate monitor is not allowed to be used frequently, so it is impossible to continuously monitor the fetal heart rate and fetal movement.
Let’s answer the next question: Why monitor fetal heart rate and fetal movement?
Fetal heart rate is an important manifestation of fetal vital signs. If the fetal heartbeat is abnormal, it indicates that the fetus is currently in difficulty or danger. Modern medicine has proved that due to placental umbilical cord factors, such as the umbilical cord wrapping around the neck (30% of pregnant women have this phenomenon), insufficient blood supply to the placenta and maternal factors, such as pregnancy-induced hypertension, overwork, etc., may cause fetal intrauterine hypoxia, Collectively known as fetal distress. Fetal hypoxia affects the normal growth and development of the fetus and even endangers the safety of the fetus. It has become the main cause of perinatal death and neurological sequelae of newborn babies.
The purpose of antenatal fetal heart rate monitoring is to monitor the status of the fetus, as well as the early detection and correction of fetal hypoxia; to strive for delivery before the fetus is injured to reduce prenatal death.
That's why obstetrics requires you to go to the hospital once a month during pregnancy to check the fetal heartbeat -- to determine the health and safety of the fetus.
However, because the traditional fetal heart rate measurement uses Doppler technology, the excess of the safe dose will cause harm to the fetus, so continuous monitoring cannot be achieved, and only the average fetal heart rate of occasional random checks can be given, so it has no clinical significance. In the "Expert Consensus on the Application of Electronic Fetal Heart Rate Monitoring" published by the Perinatal Medicine Branch of the Chinese Medical Association in July this year, it is clearly pointed out that electronic fetal heart rate monitoring is a means of evaluating the intrauterine status of the fetus. hypoxia, so that further measures can be taken in a timely manner. Therefore, the key to fetal heart monitoring should be "continuous". Continuous fetal heart rate monitoring can not only detect the health status of the fetus at the time of monitoring, but more importantly, it can predict the health trend of the fetus to a certain extent, so as to achieve early detection, early prevention and early intervention to avoid the occurrence of adverse situations.
Therefore, the best way is to use the passive fetal heart rate monitoring patch based on the stethoscope principle to achieve safe continuous monitoring.