An irregular heartbeat, medically referred to as an arrhythmia, is common during pregnancy. Approximately 50 percent of pregnant women experience some kind of irregularity in their heart rhythm, according to Cleveland Clinic. Most of these cases are benign, meaning they do not require any medical intervention and do not cause harm. Some arrhythmias can cause damage to you and your developing baby, however, so if your heartbeat is irregular while pregnant, contact your doctor.
Although the exact cause of an irregular heart beat when pregnant is unclear, there are several factors that may contribute to an arrhythmia. Pregnancy changes the hormonal state of your body, increasing levels of estrogen and another hormone called β-human chorionic gonadotropin. This may affect the action of the cardiac ion channels, which allow sodium, calcium and potassium into and out of the cells to control heartbeat.
When you are pregnant, the volume of your blood increases to provide enough oxygen for both you and your developing baby. This increased blood volume puts extra stress on the heart, doubling the cardiac output and increasing the amount of diastolic beats.
Pregnancy may cause several different types of irregular heartbeats. Palpitations are sensations that feel like your heart is racing, pounding or skipping beats. You may feel heart palpitations in your chest and neck. Supraventricular tachycardia, or SVT, is a broad term that applies to any heart beat that is faster than normal. SVT is generally considered more dangerous than palpitations, and medication may be necessary for this condition.
Atrial fibrillation, an irregular, rapid heartbeat, is possible, but rare, during pregnancy. Most women with atrial fibrillation during pregnancy have congenital heart disease or hyperthyroidism prior to pregnancy, according to the University Hospital of Heraklion.
Heart arrhythmias during pregnancy are treated very conservatively. When an arrhythmia is discovered, your doctor will test for underlying causes. If no medical cause is found, treatment generally consists of rest and procedures called vagal maneuvers, which can help slow the heart rate. Vagal maneuvers may include applying ice to the face, massaging the carotid artery and the Valsalva maneuver, which involves forceful exhalation while holding the nose and mouth shut.
If the arrhythmia causes physical symptoms or results in low blood pressure, your doctor may prescribe anti-arrhythmic medications. No anti-arrhythmic medications are considered completely safe during pregnancy, however, so they should be avoided during the first trimester, according to Cleveland Clinic.
If you do require anti-arrhythmic medications during pregnancy, visit your doctor for regular monitoring. Your doctor will perform ECGs and measure the level of medication in your blood to make sure the levels do not become toxic to you or your developing baby.