Fetal doppler: What there is to know
A fetal doppler is used when we want to monitor and observe the growth and development of a fetus in its mother's womb. A fetal doppler will help in monitoring the fetal heart rate of an unborn baby by listening to the fetal heartbeat. You should use a doppler that is FDA approved. It can normally be used at home as it is simply designed and easy to use and comes with instructions on how to use it. The fetal heartbeat can be monitored by the fetal doppler as early as 10th weeks into the pregnancy until birth of the baby.
Put simply, the fetal doppler is a diagnostic device used during pregnancy to measure the fetal heart rate by listening to the fetal heart beat, which you also already can hear at a 7 weeks pregnant ultrasound. It emits and continuously receives sound waves that are ultra-sonic. By detecting the changes in these sound waves, it interprets these changes into what we eventually perceive as the fetus's heartbeat. It uses the physical effect that was first detected by Christian Doppler. He was a mathematician and physicist of Austrian descent. The fetal doppler comes equipped with a transducer or probe that has a varying frequency that is 2MHz-3MHz. The probe has piezoelectric crystals that are used to send short sound waves into the mother's belly. After a brief pause so that it can listen to any echo, the probe picks up these echoes that are returning form the mother's womb. By determining the direction and the depth of each echo that is picked up, it will convert this into a fetal heart beat that you will eventually hear. It is therefore important to note that what the observer hears is not an actual heartbeat from the baby but a reproduced sound.
The fetus's heartbeat simply forms high frequency sound waves that the fetal doppler will pick up and interpret into a fetal heartbeat. By listening to the fetal heartbeat, it is possible to determine the fetal heart rate. It is not easy to pick up the baby's heartbeat even when you are using a fetal doppler. You should move the probe continuously until the fetal heartbeat is picked up or heard. The picked up sound waves are normally sent to the fetal doppler's monitor from where they can be observed.
Fetal Doppler differences
Not all fetal dopplers are similar. They differ in the range of frequencies that they emit. They normally come in 2MHz or 3MHz frequency ranges but we have some that go to as high as 8MHz. It is recommended to use a 3MHz fetal doppler in the early stages of pregnancy a 2MHz fetal doppler is recommended in situations where the pregnant mother is overweight. Since it is a portable device, it requires batteries to function. Some high quality dopplers have a warning and alarm system that will inform the observer when the fetal heart rate is not within the normal range.
Whether or not a pregnant mother is using a fetal doppler, she should always make regular visits to a medical practitioner. The fetal heartbeat can normally be picked up 8-12 weeks after conception. You should therefore not worry if you cannot pick up the fetal heart reate if the pregnancy has not reached this stage of development.
There are numerous layers of tissue, fat and muscles that impede perceiving the fetal heartbeat under normal conditions. There are also additional bodily fluids that also make it impossible to hear the baby's heartbeat without any aiding device. These are the reasons why we use a fetal doppler to listen to the fetal heartbeat and determine the fetal heart rate.
The fetal doppler comes equipped with a fetal monitor. The monitor shows a distinctive heartbeat that is normally simulated from the sound waves that are picked up by the probe. A good doppler will have an Auscultation monitor which displays the heartbeat in beats per minute. An extra advantage of the fetal doppler is that unlike a stethoscope, other people apart from the observer are able to hear the heartbeat. This helps to make the moment all the more memorable thanks to the external speaker it comes equipped with. Some even have a slot that you can plug in a head piece for some privacy if you so desire.
There is however an element of unreliability that comes with all electronic devices and unfortunately the fetal doppler is no exception. And as usual, quality comes at the expense of costs. A fetal doppler however helps to give parents a sense of wellbeing and that the pregnancy is carrying on normally. It goes a long way in reducing or getting rid of any stress that the mother may have concerning the health of her baby.
A fetal doppler is however not all dashy. It has occasionally been known to provide a false feeling of well-being. Therefore it's always necessary to visit your doctor frequently during pregnancy and not to rely solely on a fetal doppler.