Understanding Ultrasound Safety: Both Sides of the Story

Is ultrasound safe during pregnancy? The answer isn’t black and white. This post dives into the research, weighing the benefits and risks, so you can feel confident making a decision that aligns with your values and perspective on pregnancy.

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If you want to spark strong feelings when talking about pregnancy, bring up ultrasound safety. Discussions about the risks, benefits, and side effects of ultrasounds can get heated real quick. But few of us really understand all the nuances of this topic or the evidence on both sides.

Initially, my perspective was shaped by birth educators I’d learned from and care providers. But I wanted to share more than my opinion with you. So I dug into the studies and other resources to better understand why ultrasounds are so controversial.

So is ultrasound safe during pregnancy? Here’s what I found:

In short, there’s no definitive answer. Like many things, this isn’t a black or white issue. There’s a lot of gray area, leaving room for personal interpretation and decision-making.

But in order to make a wise decision, you need information—you need truth. So let’s get into it.

Understanding the “Safe” Side

Many experts and women believe that ultrasound is safe and useful during pregnancy. Early ultrasounds (before 20 weeks) can be helpful in determining gestational age and identifying multiple pregnancies. They can also help providers to detect birth defects (called “anomalies”), monitor a baby’s growth, and assess the placenta’s functioning.

But are ultrasounds truly safe during pregnancy?

Short answer: Yes. There is no scientifically significant and clearly proven evidence that ultrasounds harm mom or baby.

(If you don’t agree with that, bear with me. I’ll get to the other side of things.)

The Long Answer

Several studies have examined whether ultrasound exposure poses risk. Most have found no change in outcome with or without exposure. Some have found a slight change in outcomes but still no direct harm.

For example, some studies found lower birth weight in babies exposed to ultrasounds. But the results never indicated direct harm.

In this 1996 study, the difference in birth weight was not “statistically significant,” meaning it could have been due to chance.

In this 2004 study, weight differences were due to soft tissue mass (muscle, fat, etc.) not bone structure AND the difference in size was gone by the time the kids were 8 years old.

Nearly every study concludes that ultrasounds appear to be “relatively safe.”

That said, most studies also caution against unnecessary use. A 2009 m et a-analysis states, “Based on the currently available evidence it is still prudent to expose patients to the least amount of ultrasound energy necessary to obtain diagnostic information.” (emphasis mine)

In specific cases, ultrasounds can be life-saving. One small group of studies found that perinatal mortality was reduced in pregnancies where an ultrasound was performed (compared to no ultrasound). This highlights that ultrasounds, when medically indicated, can prevent life-threatening complications.

So why do some experts and parents avoid them? Let’s explore the concerns.

Understanding the “Risky” Side

Here’s what makes the topic of ultrasound safety so complex: we can ask the same fundamental question—should we be doing ultrasounds?—and end up with surprisingly similar answers on both sides.

Both camps agree there’s a lack of strong evidence, leaving us with uncertainty rather than clear-cut conclusions.

One review states, “Routine [ultrasounds] do not seem to be associated with reductions in adverse outcomes for babies or in health service use by mothers and babies.” In other words, routine ultrasounds haven’t demonstrated clear benefits, prompting some to avoid them altogether rather than risk potential downsides.

Let’s look at the details on this side of things.

Concerns and Potential Risks

While many studies suggest ultrasounds are relatively safe during pregnancy, others point to potential risks. These findings are often from small studies or less rigorous research methods, but they still provide valuable insights.

Let’s look at several of them:

Energy exposure: Ultrasounds introduce energy into the body, potentially causing pressure oscillations, temperature rises, or gas pockets in tissues. The FDA states that “the long-term consequences of these effects are still unknown.”
Birth weight: Some studies suggest ultrasounds may lead to slightly lower birth weights, which can be linked to developmental struggles and increased health risks. (Though, as mentioned earlier, these differences are often small and may not be directly caused by the ultrasound itself.)
Fetal growth restriction: In a 1993 study, researchers found that babies exposed to 5 or more doppler ultrasound were more likely to experience fetal growth restriction (FGR). (The authors state that while it is plausible that frequent exposure to ultrasound influences fetal growth, it could also be that a mother’s stress or subsequent interventions because of doppler findings led to FGR rather than the ultrasound itself.)
Fetal malformations: There is a small potential risk of malformations (though the rate remains under 1%).
Dyslexia: One study found a higher rate of dyslexia in children exposed to ultrasounds. (The authors note, however, that this could be linked to other factors, such as a higher rate of pregnancy complications in the ultrasound-exposed group.)
Brain development: Research on mice suggests ultrasound exposure can alter brain development. Since mammalian brain development across species follows similar patterns, these findings may be relevant.
Autism-like behaviors: Another study done on mice found that 30 minutes of ultrasound exposure led to mice exhibiting “autistic-like behavior, specifically social deficits and hyperactivity in social circumstances.”
Delayed speech: One small study found evidence that kids with delayed speech are twice as likely to have been exposed to ultrasound in the womb than kids without ultrasound exposure. (The authors specifically note, though, that “it is still premature to suggest a link between [delayed speech] and exposure to ultrasound waves.”)
Preterm birth: A small study found that women monitored by ultrasound experienced preterm labor more often than those monitored by vaginal exams.
Non-right-handedness: Some studies suggest that ultrasound exposure may be linked to non-right-handedness in boys. Of course, being left-handed can be totally normal. But it can also indicate a disruption in brain development.
Fatality: One study found that routine ultrasounds may increase the risk of perinatal death by 2.4 times. While this finding is alarming, it’s important to note that the risk remains small and other factors may play a role.

While the absolute risks are small and the research limited, these findings raise an important question: With possible negative effects, can ultrasounds be routinely performed under the principle of “first do no harm”?

Private Ultrasound Clinics: Are They Safe?

Private ultrasound clinics—places offering keepsake photos or videos of your baby in the womb—are increasingly popular. However, many professionals and organizations, including the FDA, advise against using these non-medical services.

The concerns include:

Technician training: Private clinics may employ staff who lack proper training or credentials.
Regulation: These clinics may not adhere to the same safety standards as medical facilities.
Overexposure: Sessions at private ultrasounds may involve longer and/or higher-than-necessary ultrasound exposure.

Since unnecessary exposure to ultrasound may carry risks, avoiding private clinics aligns with the general recommendation to use ultrasounds only when medically indicated.

Inaccuracy and Misdiagnosis

Another concern with ultrasounds is their potential for inaccuracy. For example, ultrasounds are often used to:

Measure baby’s size
Assess amniotic fluid levels
Detect anomalies (birth defects)

These measurements have a broad margin of error (fluid, size). Even when checking for birth defects or anomalies, ultrasounds have a false-positive rate of about 8–10%, meaning 10% of the time, a doctor will diagnose a baby with a defect that isn’t there at all.

While experienced technicians can minimize inaccuracies, they cannot eliminate them entirely.

Stress and anxiety caused by a misdiagnosis can affect both parents’ well-being and pregnancy outcomes. Interventions based on incorrect findings can introduce additional risks. For these reasons, using ultrasounds prudently is key.

Times Have Changed

Now let’s talk about something that doesn’t get enough attention: most studies on ultrasound safety were conducted in the 1990s or early 2000s. And since then, a couple of big things have changed:

The upper limit of intensity increased from 94 mW/cm2 to 720 mW/cm2. (That’s nearly 8 times higher!)
Women are getting more ultrasounds than ever before.

Because of these changes, it’s tough to apply findings from decades ago. What if ultrasound exposure adds up over time, like x-rays, where more exposure increases the risk?

The truth is, we just don’t know.

Why Perspective Matters

Now that we’ve gone through the facts, let’s talk about something that’s just as important in this discussion: your perspective on pregnancy.

Here’s what I mean:

Everyone approaches pregnancy with one of two underlying beliefs—often without realizing it.

Pregnancy is a natural, safe process that can be trusted to unfold as it should, with complications being the exception rather than the rule.
Pregnancy is inherently risky and commonly involves complications, requiring frequent monitoring and intervention to manage those risks.

These beliefs aren’t just abstract ideas; they influence nearly every decision you make:

Do you fear the intensity of labor, or do you embrace it as a natural part of bringing your baby into the world?
Does your care team encourage interventions at the first sign of variation, or do they help you trust your body to do what it was designed to do?
Do you and your provider treat your due date as a hard deadline, or do you trust your baby to come when they’re ready?
Do you feel like ultrasounds are necessary to check on baby, or do you believe that your healthy pregnancy doesn’t need constant monitoring?

When pregnancy is viewed as inherently risky, frequent monitoring—like ultrasounds—can feel necessary, even when there’s no clear medical need. But when you trust that pregnancy is a natural and safe process, you might approach it differently.

Most pregnancies progress without complications, so there’s often no need to check on baby repeatedly. Instead, women can learn to tune into their intuition and listen to their bodies.

The Importance of Intuition

I believe that when intervention or an ultrasound becomes truly necessary, a mother will feel it in her heart. Trusting in the divine design of our bodies—and leaning into divine guidance—empowers mothers to customize their care without relying on routine ultrasounds.

Ultimately, how you view pregnancy shapes more than just your decisions—it influences your mindset, the care you seek, and your entire experience. Believing in pregnancy’s normalcy and safety can be a powerful compass as you decide whether interventions like ultrasounds are truly needed for your journey.

The Power of Choice and the Wisdom of Trust

When it comes to ultrasounds—or any decision in pregnancy—the key is knowing that you have a choice. You don’t have to accept routine procedures just because they’re common, nor should you feel pressured to avoid them if they align with your values and needs.

It all starts with perspective. Viewing pregnancy as a natural and safe process allows you to approach your decisions with confidence and trust, rather than fear. And when challenges arise, you have within you the ability to discern what’s truly needed.

The best advice I could give you is to follow your intuition. But good intuition is preceded by good information. Now that you know the facts, turn inward—and upward. Seek guidance and confirmation of how to approach your pregnancy.

Remember: you were made for this.

Trust your body, trust God, and lean into the wisdom that comes from both evidence and experience. After all, no one knows what’s best for your pregnancy better than you.

Until next time,

Allison

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Understanding Ultrasound Safety: Both Sides of the Story