Fetal Arrhythmias

Irregular rhythms (skipped or extra heartbeats), like premature atrial contractions (PACs), are the most common type of fetal arrhythmias. Irregular rhythms usually only require monitoring.

Bradycardia is an abnormally slow heart rate.

Tachycardia is an abnormally fast heart rate.

Heart block, also known as atrioventricular block, is a fetal arrhythmia that results when electrical signals from the heart’s top chambers (atria) are not properly communicated to the bottom chambers (ventricles). The most severe form is called complete heart block, which occurs when electrical impulses from the atria do not reach the ventricles at all. This results in the heart beating too slow. Complete heart block is often irreversible.

Fetal heart block can be caused by autoimmune diseases like lupus and Sjögren's syndrome in the mother. This is because antibodies from the mother can travel through the placenta and affect the fetal heart, including its conduction system, muscle, and valves.

Although rare, fetal heart block can also be caused by congenital heart diseases, like heterotaxy syndrome.

Most fetal arrhythmias are first detected during a routine obstetrical fetal Doppler exam or ultrasound. An obstetrician or a maternal-fetal medicine specialist may recommend the following tests to confirm a diagnosis and determine the type and severity of fetal arrhythmia. These tests are noninvasive and pose no health risks to the mother or your baby.

Fetal Echocardiogram

This specialized ultrasound helps doctors evaluate the structure, function, heart rate, and rhythm of a fetal heart. Frequent fetal echocardiograms evaluate your developing baby’s heart rate, rhythm, and function as they grow and approach delivery. 

Blood Tests

Simple blood tests can help doctors learn more about your baby’s fetal arrhythmia.

Team Approach to Care

Caring for babies in utero and their mothers requires an integrated team of specialists working together. Our pediatric cardiologists who specialize in fetal echocardiography will lead the team and help coordinate care through your pregnancy, delivery, and beyond. We work closely with maternal-fetal medicine specialists, obstetricians, neonatologists, critical care experts, pediatric heart surgeons, and others to ensure you and your baby receive comprehensive care.

Advanced Diagnostic Technology

We use highly sensitive diagnostic tools, including fetal echocardiograms, to learn as much as possible about your baby’s heart. Our experts are specifically trained to evaluate the resulting images and recognize fetal arrhythmias as early as possible.