Heart DiseaseThe heart in pregnancy:
The heart is the hardest working muscle in the human body. Located almost in the center of the chest, the adult human heart is about the size of two fists held side-by-side.
At an average rate of 80 times a minute, the heart beats about 115,000 times in one day or 42 million times in a year. During an average lifetime, the human heart will beat more than three billion times - pumping an amount of blood that equals about one million barrels. Even at rest, the heart continuously works hard.
In pregnancy, there is a large increase in blood volume. Beginning in the first trimester, the mother's blood volume increases to approximately 50 percent more than before pregnancy. This extra fluid puts an increased workload on the heart. The heart responds by increasing the cardiac output - the amount of blood that goes through the circulatory system in one minute. Other body systems also respond. Blood pressure decreases to allow flow of the increased blood volume.
During labor and delivery, there can be great changes in the heart and vascular system. Large amounts of blood move from the uterus into the mother's circulation as the uterus contracts. This causes major changes in blood pressure, heart rate, and cardiac output. Epidural or spinal anesthesia may cause blood pressure to decrease.
After delivery, cardiac output increases and the heart rate slows. Excessive blood loss with delivery can change the heart rate, blood pressure, and cardiac output.
How the heart works
The cardiovascular system, composed of the heart and blood vessels, is responsible for circulating blood throughout your body to supply the body with oxygen and nutrients.
The heart is the muscle that pumps blood filled with oxygen and
nutrients through the blood vessels to the body tissues. It is
made up of:
- Four chambers (two atria and two ventricles) that receive blood from the body and pump out blood to it.
- The atria receive blood coming back to the heart.
- The ventricles pump the blood out of the heart.
- Blood vessels, which compose a network of arteries, and veins that carry blood throughout the body.
- Arteries transport blood from the heart to the body tissues.
- Veins carry blood back to the heart.
- Four valves to prevent backward flow of blood.
- Each valve has flaps, called leaflets, that allow the forward flow of blood and prevent the backward flow.
An electrical system of the heart controls how fast it beats.
Diagnosing heart disease in pregnancy:
Heart disease is a major complication of pregnancy. It occurs in about 1 percent of all pregnancies. Sometimes, heart disease is known before pregnancy. However, some women may have unknown heart conditions that only become apparent during pregnancy.
What are the symptoms of heart disease?
The following are common symptoms of heart disease. However, each woman may experience symptoms differently. Symptoms may include:
difficulty breathing, especially at night or without exertion
inability to perform normal activities
light-headedness or fainting
palpitations (irregular heartbeat)
heart murmur or click
enlarged heart (more than the normal enlargement with pregnancy)
- cyanosis (blue-coloring due to low levels of oxygen in the blood)
The symptoms of heart disease may resemble other conditions or medical problems. Always consult your physician for a diagnosis.
How is heart disease diagnosed?
Diagnosis can be difficult because some of the normal symptoms of pregnancy are similar to the symptoms of heart disease. In addition to a complete medical history and physical examination, diagnostic procedures for heart disease may include:
- electrocardiogram (ECG or EKG) - a test that records the electrical activity of the heart, shows abnormal rhythms (arrhythmias or dysrhythmias), and detects heart muscle damage.
- echocardiography - a procedure that evaluates the structure and function of the heart by using sound waves recorded on an electronic sensor that produce a moving picture of the heart and heart valves.
Cardiac conditions and pregnancy:
Normal physical changes in pregnancy may cause problems for women with cardiac disease. Prenatal care and close watch of women with heart disease are important in healthy outcomes for mother and baby. Some common cardiac conditions that may be affected by pregnancy include the following: