The Anticipation

• Many soon-to-be parents long to hear their baby's heartbeat for the first time. This can be a very exciting moment. They haven't felt the baby move and may not have seen the baby on ultrasound yet. For many parents, hearing the heartbeat is the first concrete connection they have to their growing baby.
  
  

The Growth of the Heart

• It is not long after fertilization that a baby's heart forms. Doctors calculate gestation time starting from the first day of the mother's last menstrual period. The baby's heart starts forming at just four weeks gestation, which is approximately two weeks after fertilization. At five weeks gestation, the baby's heart divides into chambers and begins beating. At six weeks gestation, its heart is beating 100 to 160 times a minute, and blood is beginning to travel through its body.
  
  

Transvaginal Ultrasound

• The point at which one hears a baby's heartbeat will depend on which device the doctor uses. The heartbeat can be heard through a transvaginal ultrasound as early as six weeks and four days gestation. During a transvaginal ultrasound, the sonographer places a probe inside the woman's vagina. This probe sends sound waves that bounce off anything solid in her body. This forms a picture of her baby and uterus. At this time, the heartbeat is audible.
  
  

Doppler Monitor

• A woman may not have reason to have an early, transvaginal ultrasound. In that case, she will likely first hear the baby's heartbeat in her doctor's office at a prenatal exam when she uses a handheld Doppler monitor at about 10 weeks gestation. The doctor will place gel on her belly, which acts as a medium. Then she will place a wand on her belly, which is called the transducer. The heart can be heard beating from the speaker attached to the monitor.