Yes, there are apps designed to let you listen to your baby’s heartbeat using only your smartphone’s built-in microphone. The most popular is Hear My Baby Heartbeat, which has been used by over 500,000 families and costs a one-time fee of $6.99. But before you download one, it’s worth understanding what these apps can and can’t do, because the gap between the marketing and the reality is significant.
What’s Currently Available
The best-known option is Hear My Baby Heartbeat App 2.0, available on iPhone for $6.99 as a one-time purchase. It uses your phone’s built-in microphone pressed against your abdomen to pick up sounds. The app includes AI chat support, step-by-step tutorials tailored to your stage of pregnancy, and the ability to record and save heartbeat clips. You can share recordings with family through Instagram, WhatsApp, or email. The app says it works best from around 16 weeks onward, with the clearest results for many families around 27 weeks. A similar version exists on Google Play for Android users.
These apps are not medical devices. They say so themselves. They’re positioned as bonding experiences, keepsakes, and fun ways to share pregnancy milestones. That distinction matters a lot when it comes to accuracy.
How Reliable Are These Apps?
Here’s the uncomfortable truth: a Cleveland Clinic review of 22 apps that used only a smartphone’s built-in hardware (no separate accessories) found that none of them could reliably detect the fetal heartbeat. The sounds you hear through these apps may be your own pulse, digestive noises, or other internal body sounds rather than your baby’s heart.
One reason detection is so difficult is that a phone microphone simply isn’t sensitive enough to pick up a tiny heart beating deep inside your abdomen. A fetal heartbeat runs between 110 and 160 beats per minute, which is noticeably faster than a typical adult resting heart rate of 60 to 100 bpm. If the app shows a rate in the adult range, it’s almost certainly picking up your own pulse. But even if a number falls in the fetal range, that alone doesn’t confirm it’s actually your baby’s heartbeat.
A More Promising Technology in Development
Researchers at the University of Washington have developed a more sophisticated approach called DopFone. Instead of passively listening through the microphone, DopFone turns the smartphone into a miniature Doppler device. The phone’s speaker emits a high-pitched tone at 18 kilohertz, just below the range of human hearing. When that tone bounces off the fetus’s beating heart, tiny shifts in the reflected sound are captured by the microphone. A machine learning model then analyzes those shifts to estimate the heart rate.
The key difference is that DopFone actively sends a signal and measures what comes back, similar in principle to the handheld Doppler your midwife or doctor uses at prenatal visits. Clinical Dopplers use much higher frequencies (above 2,000 kilohertz), but the researchers chose 18 kilohertz because it sits within the range a smartphone microphone can record while still traveling well through tissue. A session takes about one minute with the phone pressed against the abdomen. This app is not yet widely available, but it represents a meaningful step beyond what current consumer apps offer.
Why the Wrong Reading Can Be Harmful
The biggest concern with consumer heartbeat apps isn’t that they don’t work well. It’s that they might give you false reassurance. If you’re worried because you haven’t felt your baby move and an app seems to pick up a heartbeat, you might delay seeking medical attention when something is genuinely wrong. The sound you heard could easily have been your own heartbeat or background noise that the app interpreted as fetal.
The flip side is also a problem. If the app fails to detect anything, which is common, it can trigger unnecessary anxiety. This is especially likely in early pregnancy when the baby is small and positioned deep in the pelvis, making any external detection extremely difficult.
Research on home fetal monitoring in general shows mixed psychological effects. One study of remote monitoring devices found no significant reduction in anxiety scores before and after use. The emotional experience of home monitoring is unpredictable: reassuring for some people, stressful for others.
How Professionals Monitor Fetal Heart Rate
At your prenatal appointments, your provider uses a handheld Doppler ultrasound device, which is FDA-regulated medical equipment. These devices can reliably detect a fetal heartbeat starting around 10 to 12 weeks. They work by sending high-frequency sound waves into the uterus and measuring what bounces back, with far greater sensitivity and precision than any phone microphone.
Later in pregnancy, cardiotocography (CTG) monitors track the fetal heart rate continuously alongside uterine contractions. The FDA classifies software that processes fetal heart rate data as a regulated medical device, which means it must meet specific safety and accuracy standards before it can be marketed for clinical use. Consumer apps that use only a phone microphone don’t fall into this category because they explicitly avoid claiming medical purpose.
What to Realistically Expect
If you download a heartbeat app, treat it as entertainment, not a health tool. You’re most likely to pick up any sound at all after 20 weeks, when the baby is larger and closer to the abdominal wall. Even then, distinguishing a real fetal heartbeat from your own pulse or gut sounds requires training that the average person (and the average app algorithm) doesn’t have.
For the best chance at hearing something, app makers suggest lying down in a quiet room, using headphones or AirPods, and placing the phone low on your abdomen with the microphone flat against your skin. Even under ideal conditions, many users report getting no result at all in the early weeks. The apps themselves acknowledge this, noting that the baby’s heart may simply not be large enough to detect before a certain point.
If your goal is a keepsake recording or a fun moment to share with your partner, these apps can serve that purpose with the right expectations. If your goal is medical reassurance about your baby’s wellbeing, a $7 app is not a substitute for the equipment your provider uses at every visit.