What is fetal monitoring and what is it done for?

Fetal or heart rate monitoring is a method that reports on the rhythm of the baby's heartbeat. Under normal conditions, it is practiced in the last month, starting at week 36 and every 7 to 10 days. Or during labor.

Actually, you can perform at any time of the pregnancy, but it is vital before a high-risk pregnancy. As well if the mother suffers from diabetes, hypertension or had complications in a previous pregnancy, a premature labor or if the fetus It has restrictions to grow.

The procedure will notify us if the fetal heart rate is above or below 110 to 160 beats per minute. With it, a biophysical profile will be obtained that it will allow us to determine in time if there is a risk of hypoxia or metabolic acidosis.

Types of fetal monitoring

Fetal monitoring can be of two types: external and internal. The first is always the most recommended, as it is not invasive, although it must guarantee an acceptable signal quality.

Among the factors that prevent a good transmission of the signal are the obesity of the mother, the position of the fetus or if there is polyhydramnios (a lot of amniotic fluid). If external monitoring is unsatisfactory, you have to opt for internal monitoring. The difficulty would arise if the cervix has not dilated enough.

It may interest you: Prenatal diagnosis: what it consists of and what types of tests are there


To do A simple monitoring external fetal without stress a fetoscope, with which the baby's heartbeat is heard. The mother is in lateral decubitus, semi-sitting.

The same way, I know uses a portable device to auscultate and count the heart rate. East employs Doppler ultrasound, a non-invasive diagnosis that, with the help of a transducer placed on the mother's abdomen, it generates fetus images.

ORAnother procedure fixes the transducer to the mother's abdomen with straps, allowing a continuous recording of heart rates. These go to a monitor and could even be printed. A tocodynamometer would also record uterine contractions during labor.

An external fetal monitoring is the simplest and most non-invasive way to know the heart rate of the baby inside the womb.


Reports on the well-being of the fetus and the strength of the uterus contraction. It consists of placing an electronic transducer in the form of a patch on the baby's head, connected to a cable.

It communicates with a monitor that shows heart activity. To perform this examination through the cervical opening, the amniotic sac must be ruptured and the cervix partially dilated.

The information received is more accurate and is required in cases where external monitoring does not offer assurance about fetal well-being.

Benefits of fetal monitoring

Fetal monitoring helps detect the risks of hypoxia. A timely diagnosis reduces the possibility of cerebral palsy or perinatal death. Records the rate and rhythm of your heartbeat. On the other hand, it allows the doctor to evaluate the maturity of the uterus.

In the first trimester it is already possible to know if there is a risk of miscarriage and in the second trimester, to indicate malformations. By the fifth month, anomalies can be ruled out with an effectiveness close to 100% and there is a very high percentage of diagnosis of congenital heart disease.

You can see: Ultrasound in pregnancy

What are the risks of the procedure?

External monitoring does not represent any risk. But the internal one can cause, in the part of the body where the electrode has been fixed, a mark or small cut.

It is important to note that an abnormal record or outside the accepted ranges does not always mean that the baby is at risk. There is an established relationship in studies between monitoring and augmentation of forceps, cupping, and cesarean deliveries.

Pre-procedure preparation

Preparation will depend on whether the monitoring is internal or external. For the external you have to eat some food sweet about 30 minutes before.

This in order to motivate the baby's movements in a period of 10 to 40 minutes that lasts the study. Wear light clothing or a hospital gown and, in some cases, signing a consent form is required.

What happens during monitoring?

The doctor places conductive gel, which is not risky, although it will feel very cold on the skin of the abdomen. This facilitates the transmission of sound waves.

Then he supports the ultrasound transducer and fixes it with a belt. Another external device that is still fixed is the tocodynamometer, which captures the patterns of uterine contraction.

After monitoring

In the event of the external procedure and nothing out of the ordinary is presented, no special care will be required upon completion. The doctor will remove the tapes or belts and clean the gel.

On the other hand, if it is the internal study, he will check the baby's scalp and clean the place where the electrode was installed. Thereafter, the provider may suggest other instructions regarding the remainder of the pregnancy.

Diabetic or hypertensive mothers are indicated for more frequent monitoring to analyze the vitality of the fetus.

Contraindications of fetal monitoring

Except for some discomfort caused by belts, position or stillness, there are no known contraindications in external fetal monitoring. But in the case of the internal one, the electrode can cause discomfort when being inserted. Or cause a small injury to the head or the body area that touches the baby.

Internal monitoring is not indicated if the mother has active herpes lesions on the uterus or cervix. There is a possibility that it will infect the fetus.

Fetal monitoring promotes well-being

From the first time we listened to your heart, fetal monitoring is a way of knowing with eagerness and joy the life inside the uterus. Verifying that everything is fine, that it is growing, that it is comfortable, that it has enough liquid is an indescribable emotion.

And if something does not go as expected, nothing like a diagnosis in time. This is key to assuming the treatment that brings the pregnancy to fruition and preserves the life of the child and the mother.