Ultrasound: Helpful or Harmful?

So, it’s all a little abstract, other than the nausea, and maybe some sore breasts, you are still basically feeling like yourself.  You can’t imagine that in a mere 9 months you will balloon out and eventually birth a baby, one with a personality and a destiny all its own. This is when the siren song of the ultrasounds starts calling.  It would make you FEEL pregnant if you could see the baby.  It would make it all real.


I remember one mother, frazzled and besought with four children under the age of 7, finding herself pregnant unexpectedly again. In between the meals and meltdowns, she found herself in such anxiety as she anticipated adding a fifth to this already busy household. The finances were tight and there was no family  nearby to help.  She’d never had an ultrasound in any of her other pregnancies.  We weren’t clear about when she conceived, so I  suggested an ultrasound.  That ultrasound was the best medicine for this distraught mother.  Once she saw that little heart, she fell in love


It wasn’t going to be easy, but it was hers, and that was enough to readjust her mental state. And there have been studies that have shown that women who have ultrasounds in the first trimester not only have a greater degree of attachment to their babies, but also consume less alcoholic drinks! Peeking into the mystery of human gestation is fascinating. It can also be an important tool in certain pregnancies. I’d like you to think about what an ultrasound is, from your baby’s perspective.  Similar to the echolocation system of bats, whales, and dolphins, ultrasound works by sending out high frequency sound waves, which hit the body of your baby, and are reflected back onto the probe. 


These sound waves have been recorded to be as loud as a subway train coming into a station, or 100 decibels.  Most ultrasound technicians will tell you anecdotally, that babies do indeed move away from the probe once its placed on the mother’s abdomen. Ultrasounds also generate an intense amount of heat. The amniotic fluid and other affected tissues absorb the energy from the ultrasound which increases the heat in the cells being examined. The fetus has no way to perspire, and so heat can cause trouble with fetuses. Depending on the timing of the heat exposure it can cause growth retardation and developmental defects.  


Doctors and midwives frequently caution women against taking hot baths, so why would ultrasounds – which generate more heat than a bath – be repeatedly used? Frequent ultrasound has been associated with an increase in left-handedness amongst males, which by itself is inconsequential, but does indicate some level of brain involvement.   It is also increasingly linked with autism.  And just so you are fully informed, ultrasound is not only encountered when you see your baby on the screen.  Dopplers for listening to heartbeats during pregnancy, and continuous fetal monitoring in labor are also forms of ultrasound. Unlike the larger ultrasound machines, the Doppler uses continuous ultrasound rather than a pulsating form. I know, I know, you’re barely pregnant, and I’m already frightening you!  Don’t fear, there is much you can do to lessen the ultrasound exposure in your baby.

  • Surprise! It’s a ? Embrace old fashioned surprise.  Orange, yellow, green, brown, teal, are lovely baby colors for any boy or girl you may produce
  • Ask your health care practitioner to use a fetascope, a stethoscope designed to hear a fetus’s heartbeat. They work beautifully.
  • Ask for intermittent fetal monitoring in labor, rather than continuous monitoring, which exposes baby to a lot of ultrasound. Or consider a birth center or home birth!

7295416642_8f7222dfdaUltrasound is a useful tool in many situations, and as a midwife I am frequently grateful for it’s many uses.  Here are some things that ultrasound is useful for:

  • Placental location – this is important for mothers who have bleeding later in pregnancy, and for VBAC mothers to ensure that the placenta is not covering their previous scar.
  • Threatened miscarriage – I often refer mothers to the ultrasound technician when there is bleeding in the first trimester and we are unsure if the pregnancy is viable or not. If it’s not we can use herbs and things to help if necessary, and if we see a heartbeat, then we can all breathe a sigh of relief.
  • Sometimes you just get that nagging feeling that there’s two in there.  My hands can tell, but we still need to look at the position of the twins and confirm.
  • Uncertain dates.  If a woman is uncertain of when she conceived, a first trimester ultrasound will tell us an accurate due date. After the first trimester fetal development is more varied and so a dating ultrasound is not as accurate after the first trimester

Ultrasound is a useful tool, but like most technologies in modern American maternity care – overused. One or two ultrasounds are most likely harmless, it’s the repeated use that many practitioners employ  that is of concern.  Almost always a laying on the hands is just as good.  My favorite part of the prenatal visit is checking the baby’s position. There’s so much that my hands tell me about baby in that moment, and this is useful to me throughout the pregnancy and labor. In the postpartum, I feel like I’ve known this baby all along too! Make sure your doctor or midwife is skilled in palpation, the ancient art of using ones hands to feel the baby. Those bumps and lumps mean something to a skilled maternal practitioner, and are often more adept at determining position, weight and overall health of the baby. Photo Credit, Photo Credit 3


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