1. Pregnancy
  2. Giving birth
  3. Labor and delivery

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Early Decelerations: Everything You Need to Know

Regular contractions of your uterus during labor could lead to a reduction in fetal heart rate (FHR), known as decelerations. While they don’t generally pose a threat to your baby’s health, you’ll still want to be prepared for early decelerations, just in case.

Uterine contractions which happen in the course of normal labor may temporarily (but repeatedly) interrupt the flow of oxygen to your fetus. While most babies can tolerate this oxygen shortage, some cannot. 

Fetal heart rate patterns identify which fetuses are experiencing difficulties by measuring their cardiac and central nervous system responses to changes in blood pressure and gases.

Your doctor conducts intrapartum monitoring of fetal heart rate to pinpoint unusual patterns resulting from an inadequate supply of oxygen. They can then take appropriate and timely action to prevent injury from hypoxia (or a lack of oxygen for fetal tissues). 

Decelerations represent a reduction in fetal heart rate of more than 15 beats per minute (bpm) in bandwidth amplitude. They also last for longer than 15 seconds.

Coinciding with the contractions of your uterus, early decelerations are short and shallow decelerations, with normal variability. (Note that variability is a fluctuation in the baseline fetal heart rate, whether in terms of frequency, amplitude, or magnitude).

Some believe compression of your fetus’ head, rather than hypoxia, produces early decelerations. This might happen during the early stage of labor with a premature or breech baby as contractions squeeze their head. Alternatively, an early deceleration might occur in the late stage of labor when your baby descends through your vaginal or birth canal. Their heart rate slows due to uterine contractions, in turn, causing early decelerations, which more often than not prove harmless.

It’s not uncommon for a certain degree of hypoxemia (i.e., an abnormally low concentration of blood oxygen in your fetus) to occur in childbirth. However, the repetitive nature, duration, and intensity of the phenomenon determine the impact it will have on your baby. Their natural capacity for handling this type of strain also dictates the severity of their hypoxia.

Early decelerations do not translate to a poor prognosis for your baby. For instance, fetal blood gas could be perfectly normal even if fetal heart tracing shows accelerations and/or moderate variability.

Although the presence of early decelerations don’t necessarily indicate fetal hypoxia, it does point to strong uterine contractions. That’s why your doctor should carefully monitor your fetus’ early decels as they’re more likely to be receiving an insufficient amount of oxygen.

In and of themselves, early decelerations do not translate to a poor prognosis for your baby. For instance, fetal blood gas could be perfectly normal even if fetal heart tracing shows accelerations and/or moderate variability. Furthermore, if your doctor identifies, evaluates, and manages early decels well, your little one should still have a favorable prognosis.

An abnormal fetal heart rate doesn’t always imply a serious problem. Your doctor may recommend conducting other tests to see exactly what’s happening with your fetus. Find out if electronic fetal monitoring technology is available at your health care facility. It allows your doctor to keep a close watch on your fetus’ early decelerations or any other FHR discrepancy through the use of cardiotocography (CTG). This is especially critical for babies with a greater chance of developing medical complications.

When early decelerations or similar FHR irregularities arise, your obstetrician initially tries to identify the exact cause. They’ll probably advise you to try certain strategies for increasing your baby’s oxygen supply. 

An abnormal fetal heart rate doesn’t always imply a serious problem. Your doctor may recommend conducting other tests to see exactly what’s happening with your fetus.

One technique involves changing your body position. You’ll be asked to lie down in the left lateral, knee-chest, or right lateral position to relieve compression of the large vein (or vena cava). This ups the flow of deoxygenated blood to your heart and body, including your uterus and placenta

If such steps do not improve the situation, or if further testing suggests any major issues with your fetus, your doctor might opt for immediate delivery.

During normal labor and delivery, expect to experience regular uterine contractions which trigger a reduction in fetal heart rate, or decelerations. Early decelerations are short and shallow decelerations potentially brought on by a number of different things.

One explanation for early decels is the compression of your baby’s head, as opposed to a case of fetal hypoxia. Despite the fact that early decelerations tend to be benign in nature, your doctor should still carefully monitor your fetus. This is because they’ll still have an increased likelihood of developing fetal hypoxia. 

One explanation for early decels is the compression of your baby’s head, as opposed to a case of fetal hypoxia.

If your obstetrician confirms your fetus’ heart rate pattern is in fact irregular, they’ll take active steps to locate the source of the problem. Next, they will advise you of specific techniques for enhancing blood flow and oxygen to your fetus. Should these measures fail to produce positive results, your doctor might choose to deliver immediately in order to ensure a desirable outcome.

https://www.uptodate.com/contents/intrapartum-fetal-heart-rate-assessment

https://obgyn.onlinelibrary.wiley.com/doi/pdf/10.1016/j.ijgo.2015.06.020

https://www.acog.org/Patients/FAQs/Fetal-Heart-Rate-Monitoring-During-Labor

https://obgyn.onlinelibrary.wiley.com/doi/10.1016/j.ijgo.2015.06.018

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