Fetal heart rate changes throughout the pregnancy are a common occurrence and are considered normal. Hearing the heartbeat of the baby for the very first time is like music to the ears of the parents-to-be. It is quite an emotional and overwhelming moment for the expecting mother and father. Doctors perform routine fetal heart rate monitoring throughout the pregnancy to ensure everything is under control. There are some unique facts about the fetal heart rate that every mother and father-to-be should know.
What is the Normal Fetal Heart Rate?
A normal fetal heart rate ranges from 100 to 160 bpm (beats per minute) on average. That’s pretty fast, right! But it is true. But, the fetal heart rate varies throughout the pregnancy.
Fetal Heart Rate and Its Monitoring
After conceiving successfully, the expecting mothers have to visit the doctor from time to time. The doctors must monitor the overall condition of both the mother and the growing fetus inside the womb. In every doctor’s appointment, the fetal heart rate is monitored among the other parameters.
The heart of a fetus starts to beat around 22 days after successfully conceiving. But the heartbeat can be heard for the first time around five or six weeks of pregnancy.
The Heart rate of the fetus can be checked in two ways—External fetal heart rate monitoring and Internal fetal heart rate monitoring.
External fetal heart rate monitoring is commonly performed with the help of a Doppler heartbeat monitor device for low-risk pregnancies. This is a handheld instrument that creates an audible simulation of the baby’s heartbeat. The device is placed over the abdomen for the detection of the heart rate.
Some models of this device also display the heart rate of the baby in beats per minute. However, the external monitoring method is not completely reliable and has variable results based on the location of the device over the mother’s belly.
Internal fetal heart rate monitoring is done with a vaginal ultrasound which involves a small electrode inserted through the cervix of the mother and put on the baby’s skin. The device is connected to a monitor that displays the heart rate of the baby.
This form of monitoring is only possible when the amniotic fluid sac is broken and the cervix is open. However, the procedure may be an uncomfortable experience for the mother.
Without the occurrence of these two factors, doctors cannot perform internal monitoring of the baby’s heart rate.
Change in the Heart Rate of the Fetus Throughout Pregnancy
According to a published article by Dr. Henry Knipe and Dr. Yuranga Weerakkody et al., the fetal heart rate is about 100 to 120 bpm when you are about six weeks pregnant. The fetal heart rate then subsequently increases over the next two to three weeks-
- 110 bpm – 5 to 6 weeks of pregnancy
- 170 bpm – 9 to 10 weeks of pregnancy
After 10 weeks of pregnancy, the fetal heart rate decreases—
- 150 bpm – 14 weeks of pregnancy
- 140 bpm – 20 weeks of pregnancy
- 130 bpm on full term
It is also mentioned in the article that the fetal heart rate can be different in every baby by 5 to 15 bpm.
Another study done on 21 normal pregnant women between 36 to 41 weeks of pregnancy with 38 recordings, indicated that the change in the fetal heartbeat has a relation with the fetal movement inside the womb.
So, it can be said the heartbeat of the fetus changes according to the fetal activity inside the womb. Pretty much just like ours. If we perform any physical activity our heart rate increases and when we relax our heart rate goes back to normal.
Fetal heart rate may seem scary, especially the internal monitoring but the procedure is performed commonly for all pregnant women. Unless there is any complication that may affect the baby.
Possible Risks of Heart Rate Monitoring
Yes, it is risky but it has to be performed to check any possible complications with the baby and also monitor the contractions during labor.
The external heart rate monitoring method is a non-invasive one. Hence has no complications.
However, the internal heart rate monitoring method as mentioned earlier is dicey. Also, this method is not recommended by the doctor if the mother suffers from herpes actively at the time of labor. Also, it is noted that the electrode used in the method is only removed after the delivery of the baby. If the mother suffers from any STD, it may get transferred to the baby.
Pregnancy is a complicated and scary journey, especially for the mother. But with lots of love and support from everyone along with the proper guidance of the doctor, the journey of pregnancy can pass smoothly.