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Adverse Effects of Doppler and Ultrasound During Pregnancy

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It is standard procedure to use a doppler to hear the baby’s heartbeat during every prenatal appointment with your doctor. It is also standard to have at least one ultrasound during pregnancy to determine the baby’s development. The question we should be asking is should we be using doppler and ultrasound as standard procedure during pregnancy?

There are many reasons people opt to get ultrasounds:

  • Find out the sex of the baby
  • Determine the due date
  • See your baby
  • Check the heartbeat
  • Check for multiple pregnancies
  • Check for congenital abnormalities or birth defects
  • Monitor the baby’s growth and position
  • Look at the placenta to check for problems

Many of these are great benefits of getting an ultrasound. Nevertheless, there are also risks. We need to weigh each of them to see if the benefits outweigh the risks.


Ultrasound and doppler ultrasound generate heat. Safe body temperature increases in pregnant women are up to 4.5 degrees F. Research shows that doppler ultrasound can cause significant heating. It can raise temperatures from 2.5 to 10.4 degrees F, which is beyond the level that is believed to be safe.

Possible Autism Risk

In a US study, there is speculation that ultrasound in the first trimester of pregnancy may contribute to autism. The thought is that exposure early in pregnancy could disturb brain development and alter behavior. This is especially for people who are genetically predisposed to autism.

Miscarriage and Preterm Birth

A Helsinki study showed an increased risk in miscarriages for women who received ultrasound between sixteen to twenty weeks in comparison to women who did not receive scans.

In a Michigan study, women at risk for giving premature birth were studied. One group received weekly ultrasound scans. The other group received pelvic exams. In the ultrasound group, women went into preterm labor at 52%. Only 25% of the control group went into preterm labor.

Ultrasounds Do NOT Improve Fetal Outcomes

First of all, ultrasounds are not 100% accurate at determining the development and health of your baby. There are many times the results of an ultrasound have been wrong. This is especially unfortunate for moms and dads who may be emotionally distraught at being told their baby has serious defects.

One study found that fetal outcomes were not improved for women who had an early diagnosis of placenta praevia. 250 women were diagnosed with placenta praevia out of 4,000 women scanned in the study. They were given scans between sixteen to twenty weeks. Once delivery occurred, only four women had placenta praevia. There were also 4 women in the unscanned group who were diagnosed with placenta praevia. All the women received caesarean sections and there were no improved outcomes in the babies.

In an Ohio study, babies with serious defects were studied. Some of the defects included diaphragmatic hernias, abdominal wall defects, meningomyelocele and bladder extrophy. Only 36% of the defects were found before birth. The women received between one to fourteen scans each, with an average of five scans. 3 babies out of 13 who were diagnosed before birth died. There was a only one death in the 23 babies who were undiagnosed. All babies who were diagnosed in utero were delivered by c-section. In addition, 19 of the 23 babies who were undiagnosed had safe, uncomplicated vaginal deliveries. There were lower birth weights in the diagnosed babies. They also were in utero 2 weeks less on average. The outcomes were the same in the diagnosed and undiagnosed groups.

Sadly, more babies died in the diagnosed group despite knowing about the defects in advance. In this case especially, outcomes were not improved.

A German study studies babies with growth retardation. Babies were found to be small on an ultrasound had a 44.3% chance of being delivered by c-section versus 17.4% for babies who were not diagnosed as small. Babies diagnosed with intrauterine growth retardation (IUGR) were pre-term five times more than those were not diagnosed. Pregnancies were 2 to 3 weeks shorter than than for an undiagnosed one. For babies diagnosed with IUGR, the admission rate was 3 times higher for intensive care.

My assessment in all of these cases is that doctors and patients were trying to take precautions by giving pregnant mothers extra ultrasound scans, which resulted many times in early delivery and c-sections, which may have been unnecessary. The research suggests that more babies would have survived if less interventions were taken.

My Recommendations

If you want to use doppler and/or ultrasound to check on the baby, use it less often, or just use it once to check on the baby’s health and development. An alternative to using doppler is a fetoscope. My doctor does not use fetoscopes in his practice, so I purchase one that I bring in to every appointment. It is around $10, so it won’t break the bank. The downside is you won’t be able to hear the baby’s heartbeat until you are around 20 weeks gestation.

If there are no concerns about the baby and you can be patient, it is worth it to wait until 20 weeks to hear the heartbeat. The best reason to wait is there won’t be any adverse effects to the baby from using a fetoscope to listen to the heartbeat.

I believe if you are eating an optimal diet before and during pregnancy and you are in overall good health, there is a low risk that anything would be wrong with the baby. Check out my dietary and supplement recommendations during pregnancy.

There is no alternative to ultrasound, but ultrasounds are less harmful than doppler because they use less levels of ultrasound. My recommendation is to avoid getting an ultrasound unless the doctor suspects something is wrong with the baby.

If you absolutely want to have an ultrasound, just get one around 22 weeks to check on the baby’s development. Tell the sonographer to only show you what is necessary. We didn’t find out the sex of our baby, so that saved a little time. We also declined extra pictures, which can take more time. We did get to keep 2 pictures she captured at the end! She told us that was the fastest she had ever performed an ultrasound!

Finally, do NOT get a 3-D or 4-D ultrasound! The FDA says that ultrasounds should only be performed for medical reasons and by licensed staff and they should not be used for emotional reasons.

What did you do during your pregnancies?

Adverse Effects of Doppler and Ultrasound Pinterest


  1. Kristen says:

    Yes!! I decided years ago that I didn’t want ultrasounds and I was looking for a summary of why to send to my husband. If he insists on getting one, it will just be ONE and later in the pregnancy. Forwarding this to him now!! (this is Kristen from the WOC women’s group)

    • Sarah says:

      Hey Kristen!! I’m so glad this is helpful for you. I mostly had them listen to the heartbeat via the fetoscope, but I did have them use the doppler a couple times (one of the doctors didn’t know how to use it and another time I forgot) and a bunch during labor since that was hospital policy. Ugh. If you can help it, try to just opt for the fetoscope since doppler is worse than ultrasound.

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