When can you hear the baby's heartbeat by doppler​?A Doppler fetal heart monitor listens to the fetal heart using the Doppler effect of sound transmission. The fetal heart can be heard through the abdomen as early as 12 weeks into pregnancy.

Before 12 weeks, the fetus's heart cannot be heard using a Doppler fetal heart monitor because the uterus is located in the pelvis and protected by the pelvis, and the presence of bony structures makes it impossible to hear the fetal heart.

After 12 weeks of pregnancy, the uterus moves from the pelvis into the abdominal cavity, and the fetal heartbeat can be heard. However, some fetuses still have their heart in the pelvis, and it may not be audible, which is normal.

Generally, the fetal heartbeat can be heard clearly after 16 weeks, when the fetus has completely moved into the abdominal cavity and the heartbeat can be heard clearly.