Congenital heart block is a rare complication of pregnancy associated with Sjögren Syndrome (an autoimmune syndrome) that may result in the death of the fetus or infant, or the need for pacing in the newborn or at a later stage. Doctors might detect congenital heart block before or after a baby is born. Certain diseases that may occur during pregnancy can cause heart block in a baby. Heart block is a problem that occurs with the heart’s electrical system. This system controls the rate and rhythm of heartbeats. (“Rate” refers to the number of times your heart beats per minute. “Rhythm” refers to the pattern of regular or irregular pulses produced as the heart beats.) With each heartbeat, an electrical signal spreads across the heart from the upper to the lower chambers. As it travels, the signal causes the heart to contract and pump blood. Heart block occurs if the electrical signal is slowed or disrupted as it moves through the heart.