When Can You Hear Your Baby's Heartbeat on a Doppler?

Around 12 weeks into your pregnancy, you've nearly reached the end of the first trimester, and your obstetrician will use an ultrasound device known as a fetal Doppler to check for your baby's heartbeat. Hearing the heartbeat for the first time is, in a word, thrilling. Not hearing it, on the other hand, can be nerve-wracking.

Fetal Doppler at the Doctor's Office

Some obstetricians will check for a baby's heart rate with a handheld Doppler as early as week eight. However, not hearing it this early on isn't necessarily cause for alarm (which is why some doctors don't use the fetal Doppler prior to 12 weeks' gestation).

If you are fewer than 12 weeks along and your doctor can't find a heartbeat via Doppler, they may decide to perform an ultrasound, which can detect a heartbeat at eight weeks' gestation or even earlier.

At-Home Fetal Doppler

To reassure yourself that all is well in between your scheduled OB/GYN appointments, you may be tempted to purchase one of the many home Doppler devices currently on the market.

Hearing your baby's heartbeat whenever you want to is exciting, for sure, as well as comforting, especially if you've experienced a miscarriage or other problems during a previous pregnancy. But if for some reason you don't detect a heartbeat, you may become anxious, even though it doesn't necessarily mean anything's wrong.

Furthermore, there's a lot of individual variation as to when a fetal heartbeat becomes detectable. Some women may be able to hear a heartbeat with a home Doppler device as early as eight weeks into the pregnancy, while others may not hear it until closer to 12 weeks.

These variables and inconsistencies have led some experts to advise against using the do-it-yourself devices, which are available on the internet as well as in some pharmacies and big box stores.

A commentary published in the British Medical Journal in 2009 used a case study to illustrate the potential downside of home Dopplers. The commentary describes the case of a woman 38 weeks into her pregnancy who noticed her unborn baby wasn't moving. Because she could hear a heartbeat on her Doppler device she was reassured that everything was OK and decided against calling her doctor.

A few days later, unfortunately, she went to visit her doctor, and an ultrasound scan showed that the baby had passed away. Her doctor suggested that the heartbeat she heard on the monitor may have been her own.

Of course, that's the worst-case scenario, and there's no proof that the baby’s death could have been prevented. But it points to the fact that it can be difficult, and possibly risky, for an untrained person to rely too much on these home devices.

Are At-Home Fetal Dopplers Safe?

The Food and Drug Administration (FDA) has issued a warning to people to use these home devices with caution. Handheld Doppler devices are legally marketed as "prescription devices" and, according to the FDA, should only be used by, or under the supervision of, a healthcare professional.

There is no evidence that Doppler devices cause harm to a developing baby or mother. In general, though, most experts don't encourage more prenatal testing than necessary during a low-risk pregnancy.

A Word From Verywell

If you're contemplating purchasing a fetal Doppler device for home use, talk to your doctor to weigh the risks and benefits of home testing. If you want to use your own device, your physician may be able to offer suggestions on how to use it responsibly and to your advantage.

It might be best to wait until your doctor has found a heartbeat at one of your prenatal checkups so you know for sure that it should be detectable—something to keep in mind if you're checking for the heartbeat at home and you're not yet 12 weeks along.

Once you've entered the third trimester, it's important to pay attention to your baby's movement patterns and contact your doctor if you notice a reduction in movement or any other unusual symptoms. If you're concerned for any reason, don't rely on a heartbeat monitor to determine that all is well. When in doubt, it's always best to consult your doctor.