Although fetal wellbeing can be valuably inferred from the cardiotocographic record, some mothers may find it uncomfortable. In this section, we explain how the test is conducted.
In pregnancy, cardiotocography can prove extremely useful. This test allows scientists to know whether a fetus is in good health or if there are any warning signs.
An ultrasound monitors both the heart rate of the baby and the contractions in the mother’s uterus. As well as during childbirth, it can also be used in the moments preceding it. This is essential in instances of gestational diabetes or high blood pressure in women.
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What is a cardiotocographic record?
As well as providing information on the health of the baby, the cardiotocographic registry studies its development. Various factors such as uterine contractions, heart rate, and frequency are examined. The two parameters may thus be linked.
During contractions, the umbilical cord temporarily reduces or interrupts oxygen flow. Thus, the test indicates the health of the fetus. It is also useful when determining whether or not the fetus is ready to be born.
Cardiotocograms are difficult to interpret because of their complex nature. Furthermore, the work contains several false positives (positive results that are wrongly interpreted). Due to this, biophysical profiles and ultrasounds, as well as Doppler flowmetry, are often included in the analysis.
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When does it become necessary?
Cardiotocography is usually not recommended until after 32 weeks of pregnancy. As a result of the operation, its results may not be conclusive if they are taken before.
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When a woman has certain risks for pregnancy or her baby has some abnormality, this treatment is recommended. A mother might not be aware that the fetus is moving when she is less conscious of it. Usually, gestational diabetes and hypertension are considered to be the most common causes. In addition to doing it when the child is small for their age, it is done when they are old enough to understand.
Cardiotocography is also useful in multiple pregnancies because of the increased risk associated with them. Labor may begin earlier than expected if there is an increase in amniotic fluid.
Other common signs and symptoms include:
- Fevers or ongoing infections during pregnancy.
- Membranes rupture prematurely.
- The baby is in an unusual position. An example would be the presentation of the breach.
Notes and Recommendations
It usually takes 30 minutes to complete the cardiotocographic record. A suspicious heart rate pattern should also prolong the test.
It may be necessary to keep a few records during the day or to monitor continuously. It is sometimes possible to register as an outpatient.
Readings can be conducted days after the event in these cases. In light of this, the Doppler ultrasound system should be used simultaneously with other monitoring systems. Comparing the results in this way will make comparisons easier.
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How to perform a cardiotocographic record?
Cardiotocography requires specialized equipment to be performed. Transducers make up this device. While one monitors the contractions of the uterus, the other records the heartbeat of the baby.
Mothers’ abdomens are both fitted with transducers. During the electrocardiogram, the results are simultaneously printed on a piece of paper. For every minute that passes, the paper shifts one centimeter.
Some inconveniences
The mother may feel uncomfortable during the cardiotocographic recording. Due to having to hold an upright position for so long, some women suffer from back pain.
This registry also limits women’s mobility, according to the Badajoz Health Area. Labor is often quite uncomfortable during this period. False positives, on the other hand, increase the rate of instrumented deliveries and cesarean sections.
The patterns displayed by the registry do not follow any exact standardization. This is why there are no specific criteria in the document, only recommendations about management.
How does the cardiotocographic registry work?
It is a relatively complex process that creates the cardiotocographic record. Obtaining the fetal heart rate is determined using a Doppler ultrasound, according to a study by the German Society of Obstetrics and Gynecology.
An abdominal transducer transmits ultrasound signals to the mother. The heart of the baby transmits these signals. The transducer uses algorithms to determine the frequency and then returning it to the transducer. The algorithm reconstructs the frequency based on the data.
Transducers measuring abdominal pressure are used to record contractions, meanwhile. The contractions generate a signal that can be written. It is obtained this way.
Results analysis
Cardiotocography is a complex diagnostic tool. A fetal heart rate of 120-160 beats per minute is considered normal. As a general rule, this value is higher in pregnancy that is under 30 weeks gestation.
Recordings that demonstrate the baby’s heart racing at least twice during the study are considered normal. Similar to accelerations, accelerations should be more than 15 beats above the baseline. The fetal wellbeing is thus suggested by its presence.
In addition, cardiotocographic recordings may display abnormal or nonreactive results. With contractions and movement, in this case, the baby’s heart rate does not accelerate.
A test that is complemented by others
Cardiotocography is an examination that can help to determine the well-being of the fetus. As well as measuring the baby’s heart rate, uterine contractions are monitored with this device. To check if the heart reacts adequately to movement, this is what is done.
A routine exam like this isn’t conducted. An indication is if the mother is suffering from a pathological condition that may endanger the baby. Anomalies are also reported when they are discovered.
This noninvasive test is somewhat annoying for the mother, especially while giving birth. A false positive can also be reported. Due to this, additional relevant parameters should be added.