Throughout your pregnancy, it is important to receive regular, prenatal care, in order to ensure that both you and your baby are safe and healthy. Prenatal care can help to monitor your baby's growth and development as well as ensure that your own vital signs and emotional health are good. Prenatal appointments can also help you keep track of your baby's heartbeat. Sometimes, infants can develop abnormal heartbeats, and it is important to try to identify these abnormalities as soon as possible. Abnormal heartbeats in your baby may suggest an underlying health complication.
How the Heart Works
Your heart is responsible for receiving and pumping blood throughout your body. It is made up of different chambers, including the atria (upper chambers) and ventricles (lower chambers). Blood flows through these chambers and is then pumped out of the heart and around the body. In order to stimulate a beat, your heart creates small electrical impulses. These impulses travel into the muscle cells in your heart, making them contract. This is what causes your heart to beat. A normal heartbeat follows a specific pattern and beats at a particular rate, measured in beats per minute.
Heartbeats in Infants
Your babyï¿½s heart begins to beat regularly around the 21st day of development. At six weeks, your baby's heart beats at about 100 beats per minute. This increases to 170 beats per minute by the 2nd month. Your baby's heart rate will continue to fluctuate up and down until he is born. At term, a typical baby's heart beats at about 130 beats per minute. If your babyï¿½s heart rate is between 120 and 160 beats per minute at delivery, this is considered normal and healthy.
What is an Abnormal Heartbeat?
An abnormal heartbeat is any type of heartbeat that doesn't follow the normal pattern. Your normal heart pattern is based upon your age and height. Known as an arrhythmia, there are three types of abnormal heartbeats:
- Tachycardia: If you have a tachycardia, your heart is beating too quickly.
- Brachycardia: If you have a brachycardia, your heart is beating too slowly.
- Irregular: If you have an irregular heartbeat, your heart is experiencing extra or skipped beats.
Sometimes, babies develop an abnormal heartbeat. About 1% to 2% of all pregnant women have babies with a fetal arrhythmia. Typically, these arrhythmias resolve themselves, and cause no health problems or side effects. Sometimes, however, fetal arrhythmias indicate the presence of health complications. Causes of irregular heartbeats in infants often include:
- structural problems with the heart
- genetic disease, especially heart disease
- infections, like chlamydia
- exposure to alcohol, tobacco, or drugs while in utero
Types of Fetal Arrhythmias
There are various different types of abnormal heartbeats in infants. Some are more common than others.
- Irregular Heartbeats: Irregular heartbeats are the most common type of fetal heart arrhythmia. They are often discovered before birth during prenatal appointments. Irregular heartbeats usually begin in the atria of the heart, causing extra or premature heartbeats to occur. These are usually not problematic and typically resolve on their own.
- Fetal Tachycardia: Fetal tachycardia arises in only 0.4% to 0.6% of all pregnancies. It commonly occurs in the form of sinus tachycardia, which causes an increase in heart rate when your baby breathes. Tachycardia may be caused by fetal distress, drug use, or infection. In a small percentage of cases, fetal tachycardia is the result of cardiac tumors.
- Fetal Brachycardia: Fetal brachycardia is highly infrequent, accounting for only 5% of all fetal arrhythmias. Fetal brachycardia causes your babyï¿½s heart rate to drop below 100 beats per minute for a period of five minutes or longer. It may be the result of structural abnormalities within the heart.
Complications of Abnormal Heartbeats
There are some complications associated with fetal arrhythmias. If left untreated or undiagnosed, fetal arrhythmias can become exacerbated or develop into long-standing problems. Fetal arrhythmias can:
- result in fetal distress
- make it difficult for baby to breathe
- result in fetal or infant death
There is some evidence linking fetal arrhythmias with Sudden Infant Death Syndrome.
Symptoms of Abnormal Hearbeats
Because your baby cannot tell you that she is experiencing an abnormal heartbeat, it is important that you watch out for the following signs of arrhythmia:
- excessive sleepiness or fatigue
- change in pallor
Treating Abnormal Heartbeats
Abnormal heartbeats can now be treated in utero or immediately following birth. Treatment will depend upon the cause of the abnormal heartbeat, and may include medications or surgery. Most fetal arrhythmias resolve on their own without any treatment, however, it is important that your baby be monitored regularly for recurrence.
- Medications: Medications are often used to help treat tachycardias. They work to improve the symptoms of the tachycardia and prevent future episodes.
- Radiofrequency Ablation: Is used in life threatening cases of tachycardia. Small catheters are placed inside the heart, with one placed over the area causing the tachycardia. These catheters are heated, preventing electrical impulses from passing through the abnormal area.
- Artificial Pacemaker: In cases of severe infant arrhythmia, an artificial pacemaker can be placed in the body. Pacemakers are tiny instruments weighing about two ounces. They are inserted inside of the chest and connected to the heart with special wires. This machine sends electrical impulses to the heart, causing it to beat normally.