Best Fetal Doppler Systems? Think Again!

Written by Tara Carnegie

ultrasound pregnancy

Here at Mommyhood101 we pride ourselves in in providing unbiased information and giving parents the opportunity to make informed decisions about which baby, toddler, and child products are perfect for their unique lifestyles and needs.

Many websites that are similar to ours have recently provided reviews of the Best Fetal Doppler systems, providing their opinions about several systems currently available on the market.

But there are some products that we simply aren't comfortable reviewing, and providing a list of the best fetal doppler systems is a good example of that.

Many parents long to hear their little chickpea's heartbeat, kicks, hiccups, and movements. The good news is, starting at about 10-14 weeks you'll be able to hear your growing little pea, using of several fetal doppler sound amplifiers available on the market. The bad news is, it is not only illegal to purchase a fetal doppler system in the USA without a prescription, it can also be dangerous for your unborn baby.

Thus, we have chosen not to recommend fetal doppler systems for home use. And let us explain why.

While your obstetrician will use a fetal ultrasound or fetal doppler to listen to your baby's heartbeat, we recommend steering clear of home-use baby doppler systems. As the FDA states, using ultrasound or doppler devices at home increases the potential for harm to the fetus because they are more likely to be misused or over-used.

Using ultrasound or doppler devices at home increases the potential for harm to the fetus. - The FDA

What is a Fetal Doppler?

Fetal doppler systems send microwave acoustic signals (usually at about 2-3MHz) into the womb and measure how the signal changes when it comes back to the device. That frequency change when the signal comes back to the device gives the system information about sounds emanating from the womb. In other words, a fetal doppler system actively sends acoustic radiation into your womb, and uses them to measure what's going on.

Fetal doppers are actually illegal to sell in the USA without a prescription (see the FDA statement here), which is why all of the Baby Doppler products on Amazon have removed that term entirely from the titles and descriptions. And there are also several systems, such as the Up and Raise system, and Medvat system, that are actually misleading parents into thinking they are buying a simple sound amplification system while in reality, they are selling rebranded fetal doppler systems.

Fetal dopplers are illegal to purchase without a subscription.

fetaldopplernope

What is a Fetal Sound Amplifier?

In theory, a fetal sound amplifier (not fetal doppler) is completely passive and simply places a powerful microphone against your tummy to listen in on what's going on in your womb. No signals are being sent into your tummy, it simply reads and amplifies the sounds coming out of your womb. Sounds better, right?

It is. But they don't work very well at all, and tend to be full of static and fuzz. A good example is the Summer Infant Heart-to-Heart Prenatal Listening System, which is pretty poorly reviewed. So unless you're already 25-30 weeks along, you won't be able to hear much with a basic fetal sound amplifier. In contrast, the fetal doppler systems do tend to give a better quality sound with less static and fuzz, but we do not recommend purchasing them given the risks to your fetus.

Unless you're already 25-30 weeks along, you won't be able to hear much with a basic fetal sound amplifier.

What are the Risks of Fetal Doppler?

Radiation. That's right, fetal doppler introduces radiation into your womb, in the form of non-ionizing acoustic microwave radiation. We know that people are constantly exposed to radiation, with some examples being medical imaging, research laboratories, airline travel, tobacco (yes, it contains radioactive polonium-210), televisions, airport x-ray systems, radon gas, and more. And we also know that it takes prolonged moderate-intensity (or higher) exposure to produce teratogenic (mutation) or carcinogenic (cancerous) effects.

Fetal doppler directly sends acoustic radiation into the womb, exposing your developing fetus. Of course, this is low exposure for a short period of time, so the risks are likely low. However, many of the fetal doppler systems are not medical-grade devices, meaning that there is minimal control over the reliability (its frequency and amplitude) of the doppler waves being produced. That is cause for concern.

There are two general ways that fetal doppler can possibly damage your fetus: thermal and non-thermal mechanisms. Thermal refers to the fact that ultrasound heats tissues (body, brain) above normal temperatures and can induce damage (see a paper about this here). According to some research, thermal risks are most important during the first trimester (during organ development) or second and third trimester (during cell migration). Non-thermal refers to the fact that ultrasound can cause mechanical strain on human tissue due to things called cavitation, radiation force, and acoustic streaming. We're scaring ourselves just writing that down!

Using it Incorrectly and Stressing Out! We know you're smart, and we know you can read instruction manuals. But there's a reason that fetal doppler systems should be medical-grade and FDA approved, and there is a reason they are only available by prescription or for use by a licensed medical provider. The reason is that improper use can cause a few things. First, what if you can't find your baby's heartbeat? Will you panic? Second, what if the baby's heartbeat is faster or slower than you think it should be? Will you panic? You probably will, but it will also likely be unjustified panic! Moms using fetal doppler monitors pick up on all sorts of sounds that they mistake for the baby's heartbeat: their own heartbeat, stomach rumblings, and fetal movement. Only an expert trained in using fetal doppler can do this correctly, so leave it to the experts. And not to mention the stress that you'll experience if you can't find your baby's heartbeat, and we know that stress during pregnancy is one of the most important risk factors for adverse pregnancy events and long-term impacts on the growing child. So why stress yourself out even more!?

Missing Something Important. Because you're not trained in using this type of medical system, you're very unlikely to notice if something actually is amiss with your baby's heartbeat or movement. So even if you do find your baby's heartbeat, you probably would not be able to identify something as suspicious even if you heard it loud and clear. And there are cases where a mom-to-be listened to their baby's heartbeat at home and were reassured that everything was fine, so they didn't call their doctor about some symptoms they were having. And guess what, they were wrong and lost their baby as a result (see this published medical report here).

What Should You Do Instead?

We propose there are basically three options. One is to use fetal doppler in spite of our advice. You're an adult and can make your own decision! Two is to purchase a fetal sound amplification system, but as we said earlier they are pretty poor overall. Third, just rest assured and call your doctor whenever you think something might be wrong with your baby! There is no sense in trying to listen and diagnose things yourself if you're not a trained medical professional.

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