To ultrasound or not to ultrasound? That is the question.
For most pregnant mamas, ultrasounds are just a given. Of course I’ll get ultrasounds!
But there are actually some potential risks when it comes to ultrasounds. And studies haven’t shown any improvement in fetal outcomes when diagnostic ultrasounds are used.
As a natural mama, we want to avoid as many interventions as possible during pregnancy and birth. But, if you’re anything like me, you might want at least one baby ultrasound throughout your pregnancy to check for baby’s anatomy and make sure everything is OK.
And that’s cool. There may be a sort of “middle way” when it comes to baby ultrasounds, which I detail below.
But just know that, while ultrasounds may be beneficial, they are not evidence-based, mandatory, or without risks.
Benefits of baby ultrasound
There may be a number of benefits to having an ultrasound during pregnancy.
Some studies have concluded that a baby ultrasound before 14 weeks gestation is the most accurate way to predict the due date. Some studies also found that when women had an ultrasound for dating they were less likely to be induced for post-term pregnancy.
However, if you have a practitioner like a midwife who is ok with continuing to closely monitor a post-term pregnancy, this may not be an issue for you.
Other studies have found that dating from the last menstrual period was just as accurate as dating from an ultrasound.
Better yet, use our advanced due date calculator to determine a more accurate result than standard due date calculators.
Keep in mind as ultrasounds get later and later during the pregnancy, they become much less reliable in predicting accurate due dates. Ideally, a dating ultrasound would need to be done in the first trimester, usually around 8-12 weeks gestation. This can be helpful for moms who don’t have predictable periods or remember the last time they menstruated.
Sex of baby
An obvious benefit to a baby ultrasound is learning the sex of your baby.
Sure, many parents prefer to wait and be surprised, but others want to know before the birth, and the ultrasound allows that.
But there are other ways to discover your baby’s sex, including some of the non-invasive genetic screening tests that take a sample of the mother’s blood – e.g. the MaterniT21 test.
If your midwife or OB suspects you are having twins, they will recommend a baby ultrasound to confirm.
What could tip your midwife off? Symptoms of having twins include:
- Being especially famished
- Struggling with intense morning sickness
- Growing larger or faster than normal
- Palpating (feeling from the outside) two babies
- And having an extra active belly 🙂
Some women who are carrying twins don’t have any symptoms. An ultrasound is one way to confirm, although not always in the early trimesters because one twin can hide behind the other in utero.
Find out your chances of having twins in this just-for-fun quiz we created.
An ectopic pregnancy will have it’s own set of symptoms like abdominal pain and bleeding. An ultrasound can help confirm or rule out an this condition.
Typically symptoms of an ectopic pregnancy would be apparent within the first 8-10 weeks of a pregnancy.
If you believe you may be having an ectopic pregnancy, call your doctor right away, as it can be very dangerous.
Placenta previa is when the placenta attaches in the lower part of the uterus and may entirely or partially cover the cervix. Getting a baby ultrasound can help determine if you may have a low lying placenta.
Most cases that are diagnoses early in pregnancy completely resolve by delivery, so some women don’t want to know at 18-20 weeks (when the typical anatomy scan is done). Other moms would prefer to know that everything is OK so they can feel relaxed and confident walking into their natural birth.
However, one study found that early detection of placenta previa through ultrasound didn’t change fetal outcomes. It did find, however, that 246 of the 250 women who were diagnosed with placenta previa ended up NOT having it at delivery.
Additionally, placentas that partially or fully cover the cervix often cause a “warning bleed” sometime after 20 weeks but usually in the last weeks of pregnancy. This is one way moms who choose not to have ultrasounds can evaluate their risk of placenta previa.
Here’s more information about placenta previa.
Heart rate monitoring
The handheld doppler that midwives use to hear the baby’s heartbeat as well as a fetal heart rate monitor that is used at the hospital are other forms of ultrasound.
A doppler can obviously confirm the pregnancy and can be comforting to a new mom who is still not convinced she’s pregnant!
Sometimes, these ultrasounds can detect potential heart issues, which may be confirmed in the 20 week ultrasound. Interesting to note, the doppler actually has higher levels of ultrasound than those used for imaging (more on this later); however, it is used for a much shorter period of time especially for checking the fetal heart beat for prenatal appointments.
One option for moms who don’t want to use handheld dopplers for fetal heart rate monitoring can use a fetoscope. However, a fetoscope, similar to a stethoscope, can’t detect a heartbeat until 18-20 weeks gestation, while a doppler can detect a heartbeat around the 12 week mark. It may also take longer to find the baby’s heartbeat with a fetoscope, so it could be more challenging to use this device during labor when its difficult for the mother to remain still.
Bonding with baby
Some mothers, like myself, want a glimpse of their baby in utero as a way to connect with their child and to be sure everything is developing normally. I had a friend who discovered that her baby only had one kidney in her 20 week scan. She was able prepare for his birth by getting some specialists in line so her son had the best care after birth.
Risks of baby ultrasound: Safety has not been proven
The American Congress of Obstetricians and Gynecologists (ACOG) state:
“Currently, there is no reliable evidence that ultrasound is harmful to a developing fetus. No links have been found between ultrasound and birth defects, childhood cancer, or developmental problems later in life. However, it is possible that effects could be identified in the future. For this reason, it is recommended that ultrasound exams be performed only for medical reasons by qualified health care providers.” (emphasis added)
However, there is some concern about the heat generated by ultrasound machines. An increase in tissue temperature of 1.8 – 2.7 degrees F is thought to be safe. Studies have found that ultrasound, either regular pulsed or doppler (ultrasound technology that sends a continuous wave of ultrasound rather than the pulses of a traditional ultrasound), may heat tissue above the maximum safe temperature especially in and around boney areas and especially when the wand is help in place for longer than 2-3 seconds.
Additionally doppler ultrasound has been shown to cause significant heating, especially in the baby’s developing brain, which may point to continuous waves of ultrasound being more problematic than traditional ultrasound.
Animal studies have found a connection between ultrasounds and adverse effects. One study found brain hemorrhages in mouse fetuses exposed to pulsed ultrasound at doses similar to those used on human babies. Another study found that adult mice who were exposed to doses similar to ultrasound had a 22 percent reduction in the rate of cell division. These mice also experienced twice the rate of cell death in small intestine. Ultrasound at diagnostic levels has been shown to produce lung damage and focal haemorrhage in a number of mammalian species.
OK, what about humans?
A new study out of the University of Washington found a correlation with autistic boys who had ultrasound scans in the first trimester and the severity of their symptoms.
Other studies (from the 90’s, when the ultrasounds were 7 times weaker) showed increased risk of miscarriage or preterm birth. One study included over 9,000 pregnant women in two groups, one which received a routine ultrasound at 16-20 weeks and one group who didn’t. In the group who received an ultrasound at 16-20 weeks, there were 16 fetal death after the 16-20 week period while there were none in the group who did not receive ultrasounds.
A UK study found that healthy mothers and babies who received two or more doppler scans to check the placenta had more than 2 times the risk of perinatal death compared to babies unexposed to doppler.
Additionally, new studies from China point to ultrasounds carrying risks including Autism, ADHD, genetic damage, jaundice, childhood cancers, and allergies. Because we know that increases in maternal temperature can cause birth defects it makes sense that if ultrasound raises the mother’s body temperature, even locally, that baby may suffer from birth defects.
Fact: Baby ultrasounds do not improve outcomes
If ultrasounds were able to improve the outcome of babies then the potential risk may be less significant, but studies don’t show any improvement in fetal outcomes when diagnostic ultrasounds are used.
One review of studies found that ultrasound does not improve neonatal outcomes when ultrasound is used for dating, second trimester organ scan, biophysical profile, and amniotic fluid assessment in high and low risk pregnancies.
Another review found that there was no improvement in the APGAR score of babies when ultrasounds were used. This review also found that there were no more live, healthy births in the ultrasound group than the control group.
False positives are significant in routine ultrasound scans. Such false positives can create stress in moms (which is not good for the baby) and additional ultrasounds that may interfere with parents bonding with their unborn child.
Ultrasounds have not been shown to improve infant outcomes but may be increasing the rate of interventions used in pregnancies. One study found that knowledge of estimated fetal weight independently increased a woman’s risk of having a c-section, yet fetal outcomes were not improved. That means OBs may be choosing to go ahead with c-sections based on fetal size alone, even when everything else is perfectly normal.
Why a 8-12 week ultrasound usually isn’t necessary
Some doctors will do an ultrasound at your first appointment to confirm the pregnancy. My recommendation is to skip that one. You can just as easily confirm with an over-the-counter pregnancy test or a blood test; these are safer options and just as accurate.
Some practitioners believe that an early ultrasound is the best way to get an accurate due date, and some studies back this up. However, other studies say that last menstrual period is just as accurate as dating by ultrasound. And going by the last menstrual period is, of course, risk free.
Take into account if you have regular periods or how sure you are of the conception date. If you have irregular periods, determining an accurate due date may be helpful if your care provider has a hard deadline for when induction of labor needs to occur. This way you can be absolutely sure that if you go past your due date you truly are 41 or 42 weeks based on the dating ultrasound.
However if your periods are regular and/or your care provider is comfortable with gestation being long, a dating ultrasound may not be worthwhile.
What they look for in a 20 week ultrasound
A 20-week ultrasound, or anatomy scan, checks for a number of things.
The sonographer will look at and measure baby’s body parts to make sure they look normal and measure the right size. He will examine baby’s head, face, spine, abdomen, stomach, kidneys and limbs. If baby is more than 10-14 days bigger or smaller than expected you may get a revised due date (but remember, due dates are just guidelines!).
He will also look at the placenta to check for a low lying placenta which could mean placenta praaevia. But, as we discussed earlier, a low lying placenta typically moves to a more favorable position by the end of a pregnancy.
Ultrasounds are also starting to routinely examine the insertion of the umbilical cord into the placenta and the blood flow through the placenta and umbilical cord. The shape of the placenta, including the presence of any extra lobes, may also be documented.
Of course, at the 20 week ultrasound, the sonographer can usually discover the sex of your baby.
Avoid 3-D, 4-D ultrasounds!
Even the FDA warns against getting the 3-D or 4-D type ultrasounds. In their report, they state that “Ultrasounds can heat tissues and in some cases, produce very small bubbles or cavitation in some tissues.” The FDA only recommends using ultrasounds for medical use by a trained medical professional.
While moms love to see a more detailed picture of baby’s face in utero, the intensity of this ultrasound could be quite dangerous! There is just not enough data on this exposure to make it worth the risk, IMHO.
Furthermore, these types of scans are usually NOT preformed by a Registered Sonographer. There is an art to scanning, and a sonographer will control the length and intensity of the ultrasound, being much more knowledgable about this technology.
Side note: Resist the urge to buy a hand-held fetal monitor or doppler for home use since most moms are not trained to use this device.
How to reduce your baby’s ultrasound exposure
Ok, so we know that ultrasounds don’t necessarily improve baby or maternal outcome but you still want one (I get it!). Here are some tips to help you lessen your baby’s ultrasound exposure:
- After you hear your baby’s heartbeat for the first time around 12 weeks with Doppler, don’t check again until 18 or 20 weeks when your practitioner can use a fetoscope. Or better yet, skip the Doppler altogether and just wait to hear your baby’s glorious heartbeat through the fetoscope in second trimester. (Brownie points for patience!)
- Only get one ultrasound during your pregnancy. And instead of getting your anatomy scan at 18-20 weeks, ask if you can wait till 22-23 weeks. At that time, baby is bigger and your sonographer will be able to see everything he/she needs. I know many moms who have to get a follow up scan because the baby wasn’t big enough for certain measurements at 18-20 weeks.
- Ask the sonographer not to use doppler ultrasound, which gives a continuous pulse of ultrasound waves. Doppler is used to check the umbilical cord but you can forgo this assessment to reduce baby’s exposure to ultrasound waves.
- Ask the sonographer to get in and out. Some will want to stop, be extra chatty, and take lots of pictures to give you as souvenirs. Politely ask that she forgo these things and just get right to checking anatomy and getting measurements. Also consider seeing an experienced sonographer who can efficiently collect all of the necessary information. This can reduce your baby’s exposure by 15 to 20 minutes!
- Practice your prenatal exercises regularly to ensure your baby’s position is most ideal for birth. Practitioners may want to do ultrasounds in final weeks of pregnancy if they think baby is breech or posterior. And don’t forget, ultrasounds can be nearly two pounds off when predicting fetal size, so utilizing ultrasounds as a tool for checking if the baby is too big is not evidence based.
- Avoid 3-D and 4-D ultrasound shops. Don’t purchase a fetal monitor or doppler for home use.
The “Middle Way” with baby ultrasounds (aka what I did)
I was really torn with my first pregnancy, since I knew some of the risks. I decided to go ahead with only a mid-pregnancy scan and kept it to a minimum.
With my second pregnancy, I also had a single scan at 22 weeks, and the sonographer was in and out in less than 15 minutes!
I did use the Doppler with each baby just to verify the heartbeat early on in pregnancy. Once I heard it, I didn’t use again and just waited to use the fetoscope around 20 weeks.
Interesting to note, both of my children hid from the doppler. It took awhile to hear a heartbeat for either of my babies because my midwife had to keep “chasing” them with the instrument. I think instinctively my babies knew to stay away!
If I knew what I know now, I would choose to not get ultrasounds and/or dopplers since the science shows that they do not improve baby or mother health outcome. We also just don’t know enough about the side effects and risks.
Having said that, I did know a mom friend who discovered that her son had only one kidney in her 20 week ultrasound and was able to get him the best medical care right after birth… so I can definitely see how they can be helpful in some instances.
The middle way may be to get just a single ultrasound mid-pregnancy, and leave it at that.
Here’s what other natural mamas did about baby ultrasounds during pregnancy
I asked the moms on my Facebook page what they did about ultrasounds during pregnancy. Here are some of their responses.
- We only had the anatomy scan with our second baby. We planned a homebirth and wanted to make sure the baby didn’t have any issues that would require immediate medical attention (wanted to be sure the homebirth was a safe option for the baby). That’s the only one we had with him…we didn’t want any others since they weren’t necessary, so why do it? With our first, I had horrible cramping, so I had one at 7 weeks to rule out an ectopic, and we had the anatomy scan as well to rule out anything that would risk us out of a homebirth. – Lisa K
- I did not want anything that wasn’t medically necessary. With our first we didn’t have any. With our second I had one two days before he was born because I thought he had flipped to breech. With our third we had one when we found out our baby no longer had a heartbeat at 17 weeks. If there is a medical reason to get one in a future pregnancy then I have not problem having one but I still want to limit the number I receive. – Lacie D.
- We didn’t get any. There wasn’t anything it could tell us that we were interested in knowing (we didn’t want to know the sex, the midwife palpitated position, I had charted my ovulation, no family history of genetic disorders or other problems). Since we didn’t need one, it seemed silly to pay for and go through one just for the heck of it knowing there are risks, albeit extremely small. – Roxanne B.
- I think it’s important to have at least one ultrasound. There are some conditions that can be seen during the diagnostic scans and if my baby had a condition that would need attention after birth I would want to know about it so I could research and prepare myself for it. – Beth T.
- With my 1st one we did when I was 8 months along bc midwife thought we were having twins. Turned out she was just situated funny, head down with her kicking my ribs, w/ my second one we didn’t not sure why. With my 3rd we got one when I ended up in the emergency room with placenta previa, and with fourth one we did to make sure placenta was in a good spot. The first two I did water births at home, third baby by c-section, and 4th in hospital VBAC w/ epidural. – Crystal CS.
- Out of 5 children only 1 ultrasound with my first. Not worth all the unknown risks for the high rate of inaccurate information and the possible cascade of further interventions based on that incorrect information. It creates doubt, which is not empowering. – Patricia V.
- With our first, we got a bunch. We thought it was fun to get to see him, and (being typical first timers) we figured it would help alert us to any potential problems. The next time around, we had 3 (10 weeks, 20 weeks, and 38 weeks) because all of the extras seemed like overkill. The 3rd time, after 2 unnecessary c-sections with unsupportive care providers and pressure because the ultrasounds showed big babies, I told my new OB that he got to do 1 around 20 weeks. I didn’t care how big the ultrasound said the baby was going to be; I wasn’t going to change my plans to have a VBA2C because of a size guess that’s notoriously inaccurate. – Elizabeth P.
- As a Registered Diagnostic Medical Sonographer here is my opinion. Ultrasound has been proven in clinical studies to be safe and effective in diagnosing medical issues in pregnancy and directly related to the fetus. There are plenty of studies that prove this. Some of the studies I have read that steer away from diagnostic ultrasounds have not had a clear basis and seem a bit fear based. However, with that being said, I don’t see a reason in fun ultrasounds or ultrasounds not done by registered sonographers. Our machines have safety settings that only a person with a well radiology based education can understand Like that of minimizing dose with ALARA, minimizing use of things like power Doppler or other unnecessary higher energies. If you go somewhere who performs for fun 3d imaging or gender fun checks, most likely you aren’t getting someone who has a bachelors degree or higher education in sonography and radiology. We find medical conditions every day by ultrasound that could potentially save you or your baby’s life. Or things like heart defects which when baby is born could then have a cardiac team waiting for him as soon as he is born. We also don’t just focus on the fetus but also look at things like the cervix, placenta, uterus and fluid. There are literally thousands of diagnostic things we can exclude or find and refer patients to the best plan given any abnormal findings. Maybe instead of asking whether to have an ultrasound we should start asking who is performing the ultrasound and what is the purpose? That way we only have the most qualified performing them as necessary. – Jessica S.
- We avoided them like the plague over over exposure worries. The Chinese have done research on fetal ultrasound exposure and it is alarming. – Shane L.
- I had 2-3 with my first pregnancy. 1 with my second-20 week scan. Even if my midwife had been ok with more, I would have declined. 1 max is our choice. – Camille E.
Conclusion on baby ultrasounds
After looking more closely into the ultrasound research, I wouldn’t have gotten any ultrasound or Doppler with either of my pregnancies. (Sorry kiddos!)
I am glad that I only got a single ultrasound with each of my babies to keep their exposure at a minimum. And, to moms facing intense pressure to get ultrasounds (whether internal or external), I’d recommend going ahead but keeping exposure at an extreme minimum.
Yes, there are cases where an ultrasound may be the right choice, but the science points to routine ultrasounds not being beneficial to a healthy pregnancy. Ultimately, you have to decide what’s right for your family and whether the benefits outweigh the risks in your case.
How about you?
Did you have an ultrasound? Why or why not?