Baby: Fetal Heartbeat
Fetal heartbeat begins around the sixth week of pregnancy, but at this stage in a pregnancy the heart is too small to be heard, even with amplification. Week twelve is generally accepted as the time when a babys heartbeat becomes audible, although even then it may be difficult to locate. Finding the fetal heartbeat is dependent on the position of the mothers uterus, whether the mother is slender or heavy, and the position of the baby in the womb (it is easier to hear a babys heartbeat from the back rather than the front).
It is a common misconception that a slower than average fetal heart rate means a woman is carrying a boy, while a quicker than average rate means she will have a girl. There is no evidence to support this theory, however, just as there is no evidence that shows that an unusually loud or quiet heartbeat means anything, good or bad. One thing that is agreed upon, however, is that hearing your babys heartbeat for the first time is an exciting and joyful experience, something to which all parents-to-be look forward.
More on Fetal Heartbeats
Physicians have a number of tools at their disposal to detect fetal heartbeat. Of these, one of the most often used is the doppler ultrasound, which sends harmless sound waves at the heart of the fetus. The beating fetal heart affects the return path of these sound waves. The instrument then translates this disturbance into a heartbeat sound that physicians and parents can hear.
When the rate of a babys heartbeat falls into the normal range (110 to 160 beats per minute) it indicates that adequate amounts of blood and oxygen are reaching the babys heart, which in turn spreads them to the rest of the babys body. Doctors continue to monitor the heart rate of a fetus throughout a pregnancy in order to ensure its continued health. While an abnormal heart rate does not necessarily indicate a serious problem, it can be an early warning sign, allowing doctors to catch any abnormality before it becomes too serious.