Why You May Not Hear Your Baby's Heartbeat With a Doppler in Early Pregnancy

One of the most exciting pregnancy milestones is hearing your baby's heartbeat for the first time. If you are at least eight or nine weeks along at your first prenatal visit, your doctor or midwife may use a fetal Doppler (or a fetal Doppler stethoscope) to pick up the sound of your baby's heart beating.

But sometimes, the sound of a fetal heartbeat is not detected with a Doppler. If you were expecting to hear your baby's heartbeat and you can't, you may be disappointed and even worried. While the silence could mean that you're having a miscarriage, that's not always the case. There are many common, non-emergency reasons why you may not hear your baby's heartbeat with a Doppler in early pregnancy.

It's Too Early in Your Pregnancy

If your due date was calculated based on the first day of your last period (LMP), you might not be as far along as you thought—especially if your periods are irregular or you were not certain when you last had one. Meaning it could simply be too early in your pregnancy to detect a heartbeat using a Doppler.

If your due date is uncertain, your health care provider might do an ultrasound, which is a more reliable way to estimate the age of a pregnancy. Or they may have you come back for a second prenatal visit sooner than you would otherwise (generally one or two weeks, instead of four). A fetal heartbeat can be seen on an ultrasound before it can be heard on a Doppler.

You Have a Tilted Uterus

The way your uterus is oriented in your pelvis can affect how easy it is for a fetal Doppler to pick up the sound of your baby's heartbeat. If you are one of the roughly 20% of people with a uterus whose uterus is retroverted (aka tilted or tipped), it means that your uterus is farther away from your abdominal wall than the more common anteverted position, and that could make it challenging to hear the fetal heartbeat.

Not only is the fetal heart farther away, but loops of bowel may be in between the uterus and your abdominal wall where the Doppler is being placed. The combination of these factors blocks the ability of the Doppler to function properly.

If this is the case for you, don't worry. As your pregnancy goes along, your uterus will enlarge and move closer to your abdominal wall. Plus, your baby's heart will get bigger and stronger. The fetal Doppler will work better as you get into your second trimester.

Your Baby Is Hard To Find

It could be possible that your baby is too hard to find for a Doppler to detect a fetal heartbeat, remember that your baby is very small early in your pregnancy. A Doppler needs to be able to zoom in on the fetus in just the right way to pick up the sound of the heartbeat.

It takes patience and a bit of luck to find and catch the sound of your baby's heart beating with a Doppler. Waiting as your doctor or midwife is searching might seem like forever, but it should take only a few minutes as your baby gets bigger.

The Doppler Is Being Affected by Body Fat

Body fat can interfere with how sound travels and that may affect the Doppler's ability to pick up the sound of your baby's heartbeat. When this is the case, an ultrasound can be used as an alternative to a Doppler. With an ultrasound, your health care provider should be able to see the fetal heartbeat by placing the transducer on your lower belly.

If the heartbeat can't be seen on a regular ultrasound, a transvaginal ultrasound (in which an ultrasound wand is inserted into your vagina to provide a closer view of your uterus) might be recommended.

Your Placenta Is in the Way

Another reason why your doctor or midwife may not be able to hear the fetal heartbeat with a Doppler at your first prenatal visit is that your placenta is in the way. If your placenta is growing on the anterior or front wall of your uterus, the Doppler might only be able to pick up the blood flow through your placenta (essentially your own heartbeat).

When this sound is loud, it's harder to pick up the faint sound of a first-trimester fetal heartbeat. Again, don't worry. As the size of your baby and your baby's heart increases, the Doppler will work just fine no matter where your placenta is.

You Are Using a Home Fetal Heartbeat Monitor

Over-the-counter fetal heartbeat monitors should not be used to determine or track fetal health. If you are having trouble hearing your baby's heartbeat while using an at-home Doppler monitor and you are in the first few weeks of pregnancy, remember that the device you are using is not the same grade or quality as the fetal Doppler used by medical professionals.

An at-home monitor will not be as sensitive or project sound in the same way as a medical-grade model. It's also important to acknowledge that without a medical professional's training, you may not know what kind of sound to listen for.