The most wonderful, yet scariest time for a mother are those nine months leading to the birth of their baby.

Every kick makes you smile, every twinge makes you worry. You look forward with anticipation for each doctor visit knowing you’ll get to hear your little one’s heartbeat, and possibly see them as well.

But those four weeks or longer between the visits can feel like an eternity. Having your own home doppler can help you feel more connected to your child, and give you peace of mind during the wait.

A fetal doppler is a handheld heart monitor that allows you to listen, or record your baby’s heart rate while they are still in the womb.

This machine was originally for use only by medical professionals during pregnancy to help monitor the health of babies during a mother’s prenatal visit.

How Does it Work?

The fetal doppler uses a concept known as the “doppler effect,” which was discovered in 1842 by Christian Doppler. The basic premise of the doppler effect is that sounds can change in pitch by moving an object further or closer to a second object.

The sound, or wavelength, will vary depending on the distance. It is like when an airplane flies overhead. The engine seems to begin with a deep rumble, which then changes to a higher roar as it passes overhead and is closer to you. The sound’s pitch again changes as it moves forward.

The same is true for a fetal doppler. Ultrasonic waves are let out from the doppler. The second object that is used in this case would be your child’s heart.

As the heart beats, that movement changes the pitch of the doppler. The doppler then translates the heartbeat into the sounds that the mother will hear in speakers or headphones.

Hearing the little pitter-patter of their heart can bring you closer to your child. Even when you begin to feel those thuds inside your stomach, you may still enjoy pulling out the doppler every now and then to be able to hear as well as feel them. It is a very reassuring and soothing sound.