Many new parents anxiously await the chance to hear their baby's heartbeat for the first time. Although the heart develops fairly quickly after conception and can be visibly detected, it takes several weeks to be able to hear it. The age of your baby when you hear his heartbeat for the first time depends on which method is being used.
Heart Development
An unborn baby's heart begins to form shortly after implantation in the uterus. By the fifth week of pregnancy, it starts to beat and beats regularly at six to seven weeks into pregnancy. The American Academy of Pediatrics states that once a heartbeat is confirmed, the chance of the pregnancy continuing ranges from 70 to 90 percent.
Ultrasound
Although an unborn baby's heart starts beating in the fifth week of pregnancy, it is still too small to hear. At this stage, it can be seen on a vaginal ultrasound as a flickering light. The American Pregnancy Association states that the normal heartbeat at this stage is about 90 to 110 beats per minute. By the ninth week of pregnancy, the normal heartbeat range increases to 140 to 170 beats per minute and may be audible during a standard ultrasound.
Doppler
A Doppler is a handheld machine that bounces sound waves off the baby's heart and picks them up in a receiver, converting them into an audible heartbeat. Marjorie Greenfield, M.D., states that you may be able to hear an unborn baby's heartbeat during the ninth or tenth week of pregnancy and can hear it consistently by the twelfth week. At this stage, the normal heart rate will be between 120 and 160 beats per minute and may differ according to the baby's activity level.
Stethoscope
According to the American Pregnancy Association, you can hear an unborn baby's heartbeat with a stethoscope around 17 to 20 weeks into pregnancy. A special stethoscope called a fetoscope or the concave side of a regular stethoscope may be used by pressing firmly into the mother's abdomen. When using a stethoscope, the heartbeat is best heard over the baby's back.
Considerations
When using a stethoscope or Doppler, it is possible to pick up the mother's heartbeat instead of the baby's. The mother's heart rate will be under 100 beats per minute, while the baby's will be over 120 beats per minute. The doctor or nurse may feel the mother's pulse and count the number of beats each minute to make sure the right heartbeat is being detected. Keep in mind that the ability to detect your baby's heartbeat depends on the baby's position inside the uterus and the position of the machine being used to detect it.
