Pregnancy is truly a magical time in a woman’s life and proper prenatal care ensures that this moment is even better. Good prenatal care includes various types of exams, including cardiotocography1.
For those who have already had a baby, it will be easier to recognize cardiotocography. Do you know those devices placed on a pregnant woman’s belly during labor? In movies where a birth takes place, especially if it’s a vaginal delivery, you will certainly see a cardiotocography monitor and its electrodes appear.
What Does the Cardiotocography Monitor Do?
This cardiotocography device monitors the baby’s heartbeat and also the mother’s uterine contractions, and it can show whether or not the woman is in labor. Cardiotocography before delivery is very important to show if birth is approaching and how the baby’s heart rate is, and consequently if there is fetal distress due to deceleration of the heart rate.
It’s most common for the doctor to recommend cardiotocography toward the end of the pregnancy, so it’s possible to know if everything is okay with mom and baby. The cardiotocography exam is interpreted from a chart that displays the peaks of both the fetal heartbeat and uterine movements. If there’s a contraction, the electrodes placed on the belly will detect it, and this shows as up and down waves on the paper. Very similar to an electrocardiogram, cardiotocography is very effective.
Explainer Video
During the Cardiotocography Exam
The electrodes are placed at strategic points on the pregnant woman’s belly and a specialized professional will look for the baby’s heartbeat with one electrode while the other monitors the uterus.
Some cardiotocography exams also include fetal movement monitoring. If the mother feels the baby move, she presses a button similar to a hospital room call bell, the kind used to call the nurse. The mother can be monitored for about 20 minutes, providing a complete report of movements, whether contractions are present, and if they are regular.
Stimulus and Baby’s Reaction
In maternity emergency departments, this exam is performed quite frequently, including checking the fetus’s reaction when a buzzer is sounded. A buzzer? Yes! These cases are more delicate; usually, if the mother complains about changes in the baby’s movements, for example decreased or absent movements, this method may be used during cardiotocography2.
The baby really gets startled—believe it. The buzzers are usually used when the baby is sleeping, in order to wake them up for a more complete evaluation. Even though the baby does not hear in the same way we do outside, we might get the impression that the sound was extremely loud, but don’t worry, the baby is protected by a layer of amniotic fluid that “cushions” the sound impact3.
To assess possible fetal distress, the baby’s heartbeat is evaluated. The normal range is above 120 bpm, but in some cases, it can drop to 80 bpm. This can happen for various reasons, including compression of the umbilical cord.
During a contraction, it is possible for the heart rate to slow down but it’s not too worrisome; it is up to the doctor to assess each case individually. Remember that a single episode of a slowed heartbeat is not alarming by itself, but if the baby has a series of decelerations during the exam and for a long period, over 8 minutes, that’s when it becomes concerning.
But cardiotocography can also detect an acceleration of the baby’s heartbeat; if it reaches 180 and remains there for more than 15 minutes, the doctor will likely opt to proceed with delivery. Pregnancies that go beyond the usual term are often subjected to cardiotocography exams, at least every 2 days until the baby is born.
Author’s Note
When I was pregnant with Luiz Eduardo, I went back and forth to the maternity hospital several times because I was already 41 weeks along and the time still hadn’t come, so I had cardiotocography frequently.
One day, he was moving less than ideal, and so the famous buzzer was used near my belly for about 4 seconds. He jumped! I’ve never felt him so agitated!
Despite my fright, today I know this exam is routine and everything was fine with my baby at that moment. He was born two days after that little scare. In any case, cardiotocography is very effective—your doctor will order it at some point towards the end, and yes, it’s well worth it.
See also: Labor – How to Recognize When the Time Has Come
Photo: Enrico Matteucci ☸
