Ultrasound: Risks/Benefits

iStock_000002952628SmallUltrasound is a screening device used to view the fetus during pregnancy. Also known as a sonogram, it has been used since World War I for many purposes. including underwater navigation for submarines. Physical therapists have relied on ultrasound since the 1940s for its heating effects, which can reduce inflammation, increase local blood flow and breakdown scar tissue. Since the 1960s, ultrasound has replaced X-rays as the primary method of fetal imaging in pregnancy. We now know X-rays are considered dangerous to the fetus and are rarely used during pregnancy. Initially ultrasound was a screening device to look for high risk conditions. However now it has become routine for all women, regardless of their risk status.


Ultrasound is an ultra high frequency sound wave—above the range of human hearing— that generates an image of the fetus in utero. From a transducer or a probe placed deep within the vagina (in early pregnancy) or on the surface of the abdomen (second and third trimesters), sound waves are emitted at millions of cycles per second. A pattern of echo waves creates a picture from a variety of surfaces—from fluid and soft tissues to a boney skeleton. Modern ultrasound energy intensities are higher than ultrasound of earlier decades. In obstetrics the following ultrasounds and energy exposures are used:

  • Standard scan. The standard scan is used on the abdomen after early pregnancy. Provides a brief pulse ultrasound of lower exposure
  • Trans Vaginal ultrasound. Used in early pregnancy. High exposure levels due to close proximity of probe to early developing fetus. Uncomfortable procedure has been called “diagnostic rape” by some women.
  • Doppler ultrasound. Used by many obstetricians and midwives in stethoscopes, they provide relatively low exposure level.
  • Fetal monitors: used in late pregnancy and during labor to monitor baby and heart level.
  • 3-D Ultrasound. To generate 3-D images of the developing fetus. High level of exposure.
  • 4-D or Dynamic 3-D Ultrasound: Uses specially designed scanners to look at the face and movements of the baby. High level of exposure.
  • Fetal Echocardiography: Uses ultrasound waves to assess the baby’s heart in suspected congenital heart defects.


  • Confirm early pregnancy using a vaginal ultrasound
  • Detect multiple births
  • Calculate due date through measurements of fetus’ skull, femur, or crown-rump length (done in second trimester)
  • Inspect fetal organs for growth and development
  • Check gender
  • Verify fetal position and breech presentation
  • Inspect the placenta and placement.
  • Many expectant parents are excited to see the ultrasound including the 4D sonogram technology that makes it possible to clearly see a baby close up.


  • The long term effects of repeated ultrasound exposures on the fetus are not fully known. It is recommended that ultrasound only be used if medically indicated.” (American Pregnancy Association)
  • 40% of abnormalities are missed or go undetected  according to a recent study in Brisbane.
  • Causes anxiety and stress for parents who are given abnormal results or false positive findings.
  • Ultrasound heats the tissue and researchers suspect that the waves cause small local gas pockets which vibrate and collapse called cavitation. The gas can reach up to temperatures of thousands of degrees (Celsius) leading to production of potentially toxic chemical reactions.
  • Studies done on mice have shown intestinal bleeding caused by changes in the cells. Scientists conclude that there would be similar effects in humans.
  • Ultrasound has been linked to the following abnormalities:
    • Left handedness in children who are supposed to be right-handed. Although there is nothing inherently wrong with being left handed, the change is attributed to a subtle damage to the brain. Males are more affected than female fetuses, probably because the male brain develops later.
    • Early labor, premature birth, miscarriage, low birth weight, poorer health at birth, and perinatal death.
    • Increased learning disabilities, autism, epilepsy, delayed speech  development, and dyslexia


Ultrasound is used routinely and considered harmless by the medical profession, and for this reason risks are not discussed. In fact, it is presumed that use of ultrasound and the information it provides is considered valuable and desired by every woman. As with many of the tests and procedures during pregnancy, consider the risks, benefits and implications of the test.  Ultrasound is an elective test; it is not mandatory. According to Beverley Beech, the chair of the Association for Improvements in Maternity Services,

“I am not sure at all that the benefits of ultrasound scans outweigh the downsides.  We should be advising women to think very, very carefully before they have scans at all.”


During my pregnancies, I declined all ultrasound and Doppler tests deferring instead to the old-fashioned obstetric stethoscope which meant my midwife could hear my baby’s heartbeat by my 20th week—late by modern standards!  However, living in our modern world, most pregnant women will undergo a minimum number of ultrasounds. If you are having an ultrasound consider the following:

  • Use ultrasound sparingly; avoid unnecessary scans.
  • Minimize use of ultrasound before 20 weeks of pregnancy. The most sensitive time for development of brain defects is between 10 and 17 weeks of gestation.
  • Work with an experienced ultrasonography technician at a reputable site.
  • Use a scan machine that provides the least exposure in the shortest amount of time.


phpgJJk9uPM-2Lauren Feder, M.D. specializes in homeopathy, pediatrics and primary care medicine. Known for her holistically minded approach and for combining the “best of both worlds,” Dr. Feder is a frequent lecturer for parents and professionals and is the author of Natural Baby and Childcare and The Parents’ Concise Guide to Childhood Vaccinations.

Share this post.

Peggy O'Mara

About Peggy O'Mara

Editor and Publisher of peggyomara.com. Longtime natural living advocate, award winning writer, and independent thinker.

7 thoughts on “Ultrasound: Risks/Benefits

    • lisa

      how can you say there are no risks? There are numerous studies from the ’70’s onward that show risks we know and then there are the unknown risks. To deny research from so many sources all stating the same thing is to be in total denial about reality and therefore would skew your ability to make an informed choice. It is wisest to look at all the options, their risks and benefits, then make a choice based on individual circumstance.
      Personally, I have had ultrasounds ( and Doppler use) and not had them through five pregnancies.

  1. heather

    Strange. I had about 20 ultrasounds. Mostly transvaginal ones due to high Risk. My little guy was delivered at 28 weeks. 2lbs. He suffers from learning disabilities, other disabilitites and he’s even a leftie. Every single side effect. Coincidence?

  2. Pingback: Why I Declined Routine Sonograms - MommypotamusMommypotamus |

Leave a Reply

Your email address will not be published. Required fields are marked *