Fetal Arrhythmia

Fetal arrhythmia is a term that refers to any abnormality in the heart rate of your baby. These can include tachycardia–an increased heart rate–or bradycardia, which is a slowed heartbeat. The normal heart rate for a fetus is anywhere between 120 and 160 beats per minute. This is a rare condition, occurring in only 1-2% of pregnancies, and is normally a temporary, benign occurrence. However, on rare occasions, irregular heart rhythm can lead to death.

What causes fetal arrhythmia?

Fetal arrhythmia has been linked to a number of possible causes. In some cases, healthcare providers may not be able to pinpoint the source, especially if the abnormal rhythm is transient.

It is possible that high levels of caffeine consumption may cause heartbeat irregularities, but currently, only case studies have been performed. It is suggested that pregnant women limit their caffeine intake to 200mL of caffeine a day–roughly the amount found in one cup of coffee.

Also, arrhythmia may, at some point in development, be normal. During the second trimester, the baby’s heart may begin to beat irregularly as the electrical pathways of the heart mature. This is natural, and not a cause for alarm unless the irregularity lasts for a considerable period of time.

Some arrhythmias may indicate a structural abnormality of the heart, in which case your healthcare provider will run further tests and take any appropriate action necessary. If the baby’s heart rate is consistently high, your doctor may prescribe you medication that is passed through the placenta to the baby to help regulate the heartbeat.

Should I be concerned about arrhythmia?

The causes of arrhythmia are still relatively unknown. However, based on the information that doctors do have, it appears that most arrhythmias are not life-threatening to you or your baby and will resolve themselves.

In the unusual circumstance that the arrhythmia is more severe, the baby may be born with a heart irregularity that is managed throughout his or her life. There is a remote chance that fetal death may occur while in the womb or during delivery.

Next Steps

Your health care provider’s first step will be to monitor the heart rate and well-being of your baby. However, there may be questions about the condition that warrants further investigation. In these rare cases, your healthcare provider may refer you to a fetal cardiologist for further evaluation.

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Compiled using information from the following sources:

1. DiLeo, G. (2002). The anxious parent’s Guide to Pregnancy (p. 108). New York City: Contemporary Books.

2. Fetal Arrhythmia/Dysrhythmia. (n.d.). Retrieved August 15, 2014.

3. Stephenson, E. (2010, March 19). Heart Rhythm Problems (Arrhythmias).

4. Srinivasan, S. & Strasburger, J., Overview of Fetal Arrhythmias.

5. Weber, R., Stambach, D., & Jaeggi, E. (2011, January 8). Diagnosis and management of common fetal arrhythmias.

6. Zaidi, A., & Ro, P. (n.d.). Treatment of Fetal and Neonatal Arrhythmias.