Fetal Heart Monitoring Guide

An African-American female nurse doing ultrasound examination of a pregnant woman

Jump to Classifications

  1. Reassuring
  2. Elevated Heart Rate
  3. Early Decelerations
  4. Late Decelerations

What is important in a fetal heart assessment? Let’s start with the basics. In fetal heart monitoring, two monitors are placed on the mother’s abdomen.

One will measure the contractions, while the other will measure the fetal heart rate or tones. Focusing on the fetal heart rate, certain classifications tell whether the heart rate is:

  • Reassuring
  • Elevated
  • Early deceleration (bradycardic)
  • Late deceleration (severely bradycardic)

1. Reassuring

What is reassuring? It indicates that the fetal condition is good. This is indicated during a non-stress test (NST). The presence of accelerations is considered a reassuring sign of fetal well-being. 

If the fetal heart rate increases at least 15 beats per minute (BPM) over the baseline (between 120 and 160 bpm), lasting at least 15 seconds, within a 20-minute timeframe is considered reassuring.

2. Elevated Heart Rate

What is an elevated fetal heart? A heart rate greater than 160 beats per minute (BPM) is referred to as tachycardia. Factors such as  an inadequate blood supply, medications, stress, or infection (sepsis)  can cause an elevated fetal heart rate. 

In certain conditions, the fetal heart rate can increase up to 200 bpm. A health care provider (HCP) may perform an amniocentesis to determine if there is an infection that is increasing the heart rate.

3. Early Decelerations

With early deceleration, the fetal heart rate decreases as the mom’s heart rate increases. 

During this time, the uterus is contracting and compressing the baby’s head. This creates a vagal response in the baby which causes a drop in fetal heart rate. After the quick dip, the baby’s heart rate will return to its normal baseline

Early decelerations are good. Remember, it’s good to be early.

4. Late Decelerations

Late decelerations occur when the fetal heart rate does not return to normal. They appear in a staircase pattern on the monitor. These late decelerations might indicate distress to the baby during labor. Following a contraction, the baby’s heart rate should immediately return to its baseline. 

Possible indications for this can be maternal low blood pressure (hypotension), excessive uterine activity, and reduced oxygen supply to the placenta with a condition known as placenta previa. Interventions for late decelerations are:

  1. Lower the head of the bed and turn the mom on her left side to take the pressure off the vena cava and allow blood to flow to the heart and the lungs. Note: This is a key nursing intervention so you have to keep this in mind.
  2. Re-oxygenation or the reintroduction of oxygen to the baby by giving oxygen to the mother. Give about six liters of oxygen.

This intervention will allow re-perfusion to the uterus and manage late decelerations.

If standard intervention is unsuccessful, the health care provider (HCP) will perform an emergency cesarean section (C-section). The fetus will need to be delievered immediately to restore oxygenation and resuscitation may need to be performed.

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