A technical method of recording the fetal heartbeat and uterine contractions during pregnancy, usually in the third trimester, is called cardiotocography (CTG). During pregnancy, this easy, painless, and non-invasive technique is performed to assess the health of your unborn child.

A cardiotocograph, also referred to as an electronic fetal monitor, is the device that does the monitoring. Fetal distress symptoms can be detected with CTG. CTG monitoring, which identifies infants who may be poor on oxygen, is commonly used to assess fetal health. Cardiotocography is mostly used during labor.

Working of a Cardiotocography

The mother’s contractions and the baby’s heart rate are continuously monitored by CTG. The baby’s heart rate is determined by ultrasound in external CTG monitoring. Although you cannot hear ultrasound, it is a high-frequency sound that can be sent out (emitted) and picked up by specialized equipment.

External CTG monitoring uses Doppler, a specialized form of ultrasound. This kind of ultrasonography is helpful for tracking heart rate because it can measure moving structures.

Internal CTG monitoring is a little different. By attaching a wire electrode to the infant’s scalp, this device measures the heart rate by detecting the electrical signals from the baby’s heartbeat. The mothers abdominal tension is measured by the other plate on the CTG. When the uterus contracts, this measurement is used to indicate it.

Key Features to Read a CTG

Following are the key features of reading CTG:

DR: Define risk
C: Contractions
BRa: Baseline rate
V: Variability
A: Accelerations
D: Decelerations
O: Overall impression

What Can Be Seen on Cardiotocography?

To acquire a general idea of the baby’s health, medical practitioners examine several CTG readings. They should take into account a number of factors, such as:

The heart rate of the infant. During labor, a baby’s heartbeat generally ranges from 110 to 160 per minute. An issue may be indicated if the baby’s heartbeat is regularly high or low.
The baby’s heart rate variation or variability. A baby’s heart rate fluctuating slightly from beat to beat is a positive indication that their brain is working properly.
A problem may be indicated if their heart rates remain relatively constant over an extended period of time.
The patterns of the baby’s heart rate variations in response to contractions are described.
An acceleration is a comforting indicator when the baby’s heart rate briefly rises before returning to normal.
Additionally, there may be brief drops in the baby’s heart rate (referred to as a deceleration). If it occurs at the start of the contraction and immediately returns to normal, then this is normal. On the other hand, they may indicate that the baby is having trouble if they occur without contractions, late in a contraction, or for a considerable amount of time after the contraction is over.

Uses of CTG

Your baby appears smaller than anticipated or is arriving early.
Patient blood pressure is elevated.
You have a fever or high temperature.
An infection has infected you.
During labor, fresh blood is passed.
There will be twins or more in your line of pregnancy.
Meconium has been passed from the baby’s open bowels into the amniotic fluid.
After listening with a Pinard or Doppler machine, the midwife believes there might be an issue.
If more than twenty-four hours before the start of your labor, your membranes have burst.
If your infant is in a peculiar position.
CTG can be used for 30 minutes following the insertion of an epidural or following epidural top-ups if you have one for pain management during labor.

Benefits of CTG

It is a painless process.
Early detection of fetal distress.
Lower risk of seizures in newborns.
Observation of fetal heart rate and uterine conditions.
Ability to detect problems with the placenta.
Monitoring of babies who are small or not growing properly.

Side Effects of Cardiotocography

In the internal CTG monitoring case, electrodes are attached to the baby’s scalp, which can cause minor bleeding or bruising.
CTG observation may find fetal distress, which can lead to further medical involvement.
Internal CTG monitoring may increase the risk of infection, particularly for women with certain medical conditions.
CTG monitoring may cause uterine contractions, which can be uncomfortable for some women.
CTG monitoring can cause anxiety for some women, particularly if the results are abnormal.

Procedure of Cardiotocography in India

1. Preparation

The pregnant woman is given an explanation of the process by the healthcare professional. And also makes sure she is comfortable throughout the test. Depending on her comfort level and gestational age, the woman is either comfortably positioned on her side or back.

2. Application of transducers

The woman has two transducers applied to her abdomen. The ultrasound transducer, which is the first electrical device, is placed over the region where the fetal heart rate is most audible. Measurement of uterine contractions is done by placing the second instrument, the toco transducer, over the uterine fundus.

3. Monitoring

The CTG machine records the fetal heart rate and uterine contractions for twenty to thirty minutes. Then the machine produces a graph that shows the changes in the fetal heart rate and uterine contractions.

4. Interpretation

Graph is analyzed by the doctor to assess fetal well-being. They examine the various parameters, such as variability, accelerations, decelerations, and many more.

5. Assessment of variability and patterns

Variability refers to the fluctuations in the fetal heart rate, which mean a healthy nervous system. Patterns mean an increase and decrease in heart rate. And these are evaluated for normalcy.

6. Non-Reactive Traces

If the graph shows no significant variability or abnormal patterns, it is considered non-reactive.

7. Documentation and communication

The woman and her healthcare team are informed of the results of the CTG monitoring, which are recorded in the woman’s medical records. Based on the CTG results, additional measures like more testing management adjustments or ongoing monitoring might be suggested.