How does a Fetal Doppler work?
A Fetal Doppler uses sound waves to pick up a baby’s heart beat in the womb. It listens to reflections of small, high frequency sound waves that are reflected off of the fetal heart. Low ultrasonic waves are transmitted into the womb throught the doppler's probe. As the waves bouce back, their pitch alters and this is known as the 'Doppler Shift' principle. These soundwaves are then processed and amplified so that they are audible through the doppler's loudspeaker or or through headphones.
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How safe is it to use a Fetal Doppler?
Ultrasound technology has been used by the medical profession for more than 25 years. A Fetal Doppler differs from the ultrasound scanners used in hospital that produces images of a fetus. Fetal Dopplers operate using a very low frequency ultrasound wave with minimum output.
Research has never been able to suggest that using a fetal doppler can have adverse affects on the mother or the fetus. With the more recent availability of Fetal Dopplers for home use, it is simply advised not to use a Doppler too often; i.e. not every day, and not for extended periods so only for a few minutes at a time.
The Fetal Dopplers that we hire out are CE certified and meet all EU medical requirements. |
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What do the different dopplers on the market do?
Essentially, there are two main types of Fetal Doppler available. These are ‘Sound’ and ’LCD’ models. The both operate in the same way by projecting the sound of the heartbeat through a londspeaker but the LCD Fetal Doppler also produces a reading of the heart rate on an LCD display. We also rent out the BabySonic Fetal Doppler which in addition has a waterproof probe so that it can be used during a waterbirth. |
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Why hire a Fetal Doppler?
Dopplers are available to purchase and some people like to own one outright. However, professional quality dopplers are expensive, and serve little purpose after the nine months of pregnancy, so for many, rental of a fetal doppler is the obvious choice.
In the early stages of pregnancy, Fetal Dopplers can provide a welcome reassurance, until the more obvious signs of pregnancy appear such as movement. However, women who have experienced difficult pregnancies in the past find them a comfort too.
We do however find that many women simply enjoy the experience of using a Doppler so much that they may rent a doppler for any if not all stages of pregnancy.
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Fetal Dopplers- The History
The first fetal Doppler was created by physician Dr. Edward H. Hon in 1958 as an external listening device using ultrasound wave echos to hear a fetal heartbeat.
The Doppler effect was first described by the Austrian physicist Christian Doppler (1803-1853) in 1842 and he discoved of the peculiarities of moving sound.
He explained that the perceived change of frequency in light and sound waves was due to the relative motion of the source and the observer. His ideas helped pave the way for theories including the idea that the universe is expanding, and made it possible to follow weather patterns by tracking electromagnetic radio waves.
Fetal Dopplers utlilise this `Doppler effect` to enable you to hear an unborn baby`s heartbeat so that expectant women can listen to and share the excitement of pregnancy with loved ones.
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How early can I hear my baby?
It has been reported that a fetus can be heard from as early as 8 weeks of pregnancy. However, as a rule, it is most likely that a mother can hear her baby from about week 12.
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Do I need to use ultrasound gel?
Ultrasound gel is necessary when using a fetal doppler as is conducts the soundwaves between your tummy and the fetal doppler probe, making the heartbeat more audible through the doppler. |
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How do I care for my Fetal Doppler?
All our Fetal Dopplers come with a minimum of one year manufacturers warranty. A Fetal Doppler is a sensitive piece of equipment and every care should be taken to preserve the lifespan of a Doppler. After use, clean the probe using a soft cloth and replace the Doppler in it’s packaging to protect it from dust and moisture. Do not immerse the unit in liquid at any time.
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What can I hear through my doppler?
The fetal heart sounds like the fast hoof beats of a galloping horse and if using an LCD Fetal Doppler, the heartrate will be faster that your own, ranging from about 130 to 160 beats per minute, whilst yours will be under 100 beats per minute.
You will also hear the placenta which sounds like a rushing wind. In the third trimester of pregnancy, it may also be possible to hear kicks and burps.
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