Use of Ultrasound in Pregnancy and Birth
Use of Ultrasound Devices in Pregnancy
What is Ultrasound?
Ultrasound is high-frequency sound waves, used in diagnostic testing of the fetus. It has been used in this capacity for about 50 years.
Ultrasound technology is used in several different ways. I will briefly describe the different uses applicable to pregnancy.
Ultrasound imaging: the use of sound waves to create a visual picture of the baby inside the womb.
Doppler: a hand-held device used in prenatal appointments. It amplifies the sound of the baby’s heartbeat and is heard through a speaker.
Fetal Monitor: used in hospitals to either continuously or intermittently monitor the baby’s heartbeat and the mother’s uterine contractions. Fetal monitors are not used in homebirth and so this form will only minimally address them.
Fetoscope: a special stethoscope used to hear the baby’s heartbeat; it is not an ultrasound device but the old-fashioned alternative to using a Doppler.
How is ultrasound regulated?
The medical community has decided that ultrasonography should be limited in its use and has implemented the ALARA principle for ultrasonography (as low as reasonably achievable); however, this is a highly unregulated field and opinions differ widely on how much is necessary.
Why is ultrasound used during pregnancy and what are its benefits?
The many benefits of ultrasound include the ability to find the fetal heartbeat earlier and more easily. A Doppler can find the fetal heartbeat at around 12 weeks as opposed to around 20 weeks with the use of a fetoscope. Ultrasound imaging has been called a window into the womb and is used to see the baby and find out a myriad of information about the baby. We can discover the sex of the baby, monitor growth, find birth anomalies or the lack thereof, determine the location and position of the fetus, discover ectopic pregnancies, and find the location of the placenta and its condition, among many other things.
What are the disadvantages of ultrasound?
It is hard to say if ultrasound is dangerous because so few studies on short-term and long-term effects have been done. Here are things we know about ultrasound:
Ultrasound is a non-ionizing radiation. This is not the kind of radiation that we know causes cancer, but a different type of radiation. Ultrasound waves cause a rise in temperature at the molecular level. In adults, it would seem that the cells around the area of exposure can absorb the impact of the waves. However, in the case of an embryo, the whole body is being exposed which has an unknown effect. Another effect of ultrasound is cavitation, which means that it causes gaseous bubbles to form and pulsate.
Many in the medical community believe ultrasound to be perfectly safe. However, x-rays were also believed to be safe for decades until it was proven that they caused cancer, long after the damage was done. More studies are needed to find out the effects. It seems we will have plenty of data soon, as most pregnant women do currently receive ultrasound.
Is one of these ultrasound devices safer than the others?
Surprisingly, minute for minute, the exposure from a Doppler or electronic fetal monitor is greater than the exposure from imaging. Imaging uses a pulsed, non-continuous exposure to ultrasound waves, whereas the Doppler and the electronic fetal monitor use continuous waves.
What are the psychological effects of ultrasound?
The use of ultrasound as a diagnostic tool can make it seem that any problem with the baby can be discovered, and further, that something can be done about those problems. This is true only in a very limited sense. Ultrasound cannot find every problem, but can find some. However, even when it can find a problem, there are usually very few options for what to do about that problem.
There are other tests that can be given to diagnose major problems such as Downs syndrome. If these tests show potential problems, then ultrasound can be used as a secondary tool to diagnose. Each pregnant mother should ask herself what she would do if she found out there was a problem that cannot be “fixed.” If she would choose an abortion, then there is more call for testing. If she would not abort a baby even with anomalies, then testing is sometimes unnecessary and extraneous. If the risk for problems is low (as seen with young women with a low risk of Down syndrome) then testing may be not worth the potential risk it presents.
We can have no guarantees of a perfect and healthy baby. Even with all the tests available today we do not have the capability of knowing exactly what might happen. Each pregnancy carries its own risk; we must be willing to face that risk and accept whatever outcome it brings.
Ultrasound has been shown to cause anxiety in some by repeatedly focusing on what could go wrong, and calm anxiety in others by showing parents the healthy baby inside. Ultimately, ultrasound is one cause of high cesarean rates, because of finding “problems” that we must fix rather than trusting our bodies to make a healthy baby and assuming that things are well within until proven otherwise.
What do I do with this information?
This is where you, an individual mother, need to make a choice about how you will use ultrasound technology in your pregnancy. You can choose to use it to the full standard of obstetrical care used today, or you can choose to not use it at all, but there is wide middle ground in use of ultrasound. A Doppler reading can be taken once in early pregnancy to find the baby’s heartbeat to provide reassurance, and fetoscope used from then on. One ultrasound imaging will expose baby to fewer waves than five will, especially if the frequency is low and the time exposed is minimal. The prudent use of ultrasound can be a valuable tool, used in the lowest dose necessary and in the right circumstances.
On the last page of this form you will find a number of choices. You can choose one for yourself, or write out your own plan. I will ask you to sign this form, that you understand the risks and benefits of both using ultrasound and of not using it. At any time during pregnancy you may change your mind; if this occurs I will ask you to amend your signed form.
There is much information about ultrasound; I would ask that you read not only this form, but educate yourself from many different sources and choose wisely for yourself. It is important that you use technology as you are comfortable with it; I also have a comfort level, and I will choose to refer you to another care provider if the use of ultrasound chosen by you is outside of my own comfort zone as a midwife.
As a midwife, what is your opinion on the use of ultrasound?
I recognize the value of ultrasound as a diagnostic tool, and yet because of its unproven nature, prefer to mostly use other techniques, saving ultrasound for extraordinary circumstances. During a healthy, uneventful pregnancy, I believe that ultrasound can be totally ignored, rather utilizing age-old techniques to assess the health of your baby. Use of an old-fashioned fetoscope will be used, as well as palpation, in addition to monitoring the mother’s vital signs at each visit. Keeping tabs on these signs will tell me, the midwife, if further assessment is needed. If there is a question, I will confer with other midwives; if consensus is that an ultrasound is necessary for further assessment then I will discuss this with you and we will come to a decision together about how to proceed.
Here are some instances where I would strongly recommend the use of ultrasound to rule out problems or to find out more information about what’s going on:
- • Symptoms of ectopic pregnancy are present
- • Symptoms of a molar pregnancy are present
- • Symptoms of problems with the placenta are present, such as placenta previa (placenta is lying across the opening of the uterus) or a placental abruption, meaning the placenta is separating prematurely from the uterine wall
This list is not exhaustive; there are many cases where I would talk with you about the use of ultrasound and you are welcome to bring up questions and concerns and discuss the use of ultrasound with me.
Whether to utilize ultrasound is always the mother’s decision. I can give information about whether ultrasound is indicated for each circumstance, but it is ultimately a decision you will need to make for yourself.
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Wikipedia. Ultrasound. Wikipedia 2009. Available at: http://en.wikipedia.org/wiki/Ultrasound. Accessed September 10, 2009.
Cunningham FG, Leveno KJ, Bloom SL, Hauth JC, Gilstrap LC, Wenstrom KD. Williams Obstetrics. 22nd ed. New York: McGraw-Hill Medical Publishing Division; 2005.
Wiseman CS, Kiehl EM. Picture perfect: benefits and risks of fetal 3D ultrasound. MCN, Am Jrnl of Mat/Child Nursing. Mar/Apr 2007; 32(2): 102-109. http://www.nursingcenter.com/prodev/ce_article.asp?tid=704725 Accessed on September 10, 2009.
