About Heart Development in Fetus

Time Frame

• The heart begins to develop in the 22nd day after conception, or the fourth week of pregnancy, which is the beginning of the embryonic period. During the fifth week of pregnancy the heart begins to beat and by week six the heart beat is regular. The heart is fully developed by week eight, beating 150 times per minute---twice that of an adult. An ultrasound can detect the heartbeat at week five and at week 20 a stethoscope can be used to hear the heartbeat.

Features

• The developing embryo needs blood and the heart is the organ that pumps the blood so the heart is one of the earliest organs to form in the embryonic fetus. The heart is completely formed about eight weeks after conception. Heart development involves a number of complex steps that must occur at certain times. The fetal heart continues to change during birth and immediately following birth becoming its own independent entity.

Size

• During the first few weeks in the womb the heart occupies most of the fetus' midsection. The size of the heart in comparison to the size of the body is nine times larger in the fetus than in an infant. During these early weeks, proportionally the heart is much larger than it will even be at any other time.

Growth

• In the womb the heart grows from a simple tube to a four chambered pump. Development is fast and the heart bends and twists back on itself in need of more space. During the second phase of development the two atria are partly separated and there is one large ventricle. Finally the ventricles separate completely and the heart is fully developed.

Appearance

• As the fetal heart develops it has different appearances first resembling the heart of a fish, frog, snake or turtle. During the final stages of development when four heart chambers appear, the heart is clearly distinguished as a human heart.

Misconceptions

• Before sonograms and ultrasounds some people believed that the gender of the baby could be determined by the rate of the heart beat. Studies done to answer the question, can the fetal heart rate predict the gender of the baby, concluded that it can't. In 1990 and 1996 TJ Dubous conducted extensive studies and concluded that "the fetal heart rate is not predictive of the gender of the neonate."

Warning

• Some women who take insulin or anti-epileptic drugs or have a family history of congenital heart disease might be at risk of having a baby with heart disease. The American Heart Association recommends that these women have an echo cardiogram in the early stages of fetal heart development. An echo cardiogram is also recommended when the fetal heartbeat is abnormal or hard to detect.