Too Many Ultrasounds During Pregnancy? What Expecting Parents Need to Know

Table of Contents

• Key Points
• Why This Research Matters: The Rapid Rise of Fetal Ultrasounds
• Medical Guidelines: How Many Scans Are Actually Recommended?
• Why Are Ultrasound Rates So High?
• Key Findings: What the Data Shows About Frequent Scans
• Safety Concerns: What We Know and What We Don't
• False Alarms and Unnecessary C-Sections
• Animal Studies: A Cautionary Note
• Clinical Implications: What This Means for Patients
• Limitations: What This Report Couldn't Tell Us
• Recommendations: Questions to Ask Your Doctor
• Frequently Asked Questions
• Source Information

Key Points

• Experts recommend one or two ultrasounds for low-risk pregnancies; about 80% of pregnancies are low-risk.
• Average ultrasound use reached 5.2 per delivery in 2014, a 92% increase from 2004.
• No large safety studies exist for modern ultrasound equipment, which emits eight times more acoustic energy than pre-1992 devices.
• A 2012 study linked fetal-weight ultrasound within a month of delivery to a 44% higher cesarean rate.
• Ask your doctor if each scan is medically necessary, and monitor safety indexes like thermal and mechanical indices.

Why This Research Matters: The Rapid Rise of Fetal Ultrasounds

When Milena Mrosovsky was pregnant with her son, she estimates she underwent a dozen fetal ultrasounds. "I was just happy to get my pictures and keep them in my little album," she recalls. Her experience is far from unusual — American women are getting fetal ultrasound scans at sharply higher rates than ever before, and parents have turned images of their unborn children into social media fixtures.

In 2014, the use of the most common fetal-ultrasound procedures in the United States averaged 5.2 ultrasounds per delivery, according to an analysis of data compiled for The Wall Street Journal by FAIR Health Inc., a nonprofit aggregator of insurance claims. That's a striking 92% increase from 2004. Some women report getting a scan at every single doctor's visit during pregnancy.

This matters because medical experts are now warning that frequent scans in low-risk pregnancies simply aren't medically justified — and there are unknowns about the long-term effects of modern, more powerful ultrasound equipment.

Medical Guidelines: How Many Scans Are Actually Recommended?

In May 2014, a joint statement from several medical societies — including the American College of Obstetricians and Gynecologists (ACOG) — called for one or two ultrasounds in low-risk, complication-free pregnancies. The statement was direct about how the technology should be used:

"Ultrasonogram should be used only when clinically indicated, for the shortest amount of time, and with the lowest level of acoustic energy compatible with an accurate diagnosis."

Experts in fetal medicine have long recommended that women undergo one ultrasound around the 20th week of a low-risk pregnancy. In recent years, they've added a recommendation for an earlier scan around the 12th week as well. About 80% of pregnancies are considered low-risk.

Yet a 2013 study in the journal Seminars in Perinatology, using insurance data to examine a "clearly low risk population," found a mean of 4.55 ultrasounds per pregnancy. "In low risk pregnancies, that's too many," says Daniel O'Keeffe, an author of that study and executive vice president of the Society for Maternal-Fetal Medicine.

Even the doctors involved in publishing that guideline aren't sure many of their colleagues are aware of it. "Some doctors don't read medical journals," Dr. O'Keeffe admits.

Why Are Ultrasound Rates So High?

The reasons behind the surge in ultrasounds are complex — involving a mix of malpractice fears, financial considerations, patient demand, and the sheer appeal of seeing your baby.

Fear of Missing Something

The rising usage rates partly reflect a belief among obstetricians that routine peeks at the fetus can stave off surprises. Obstetrics pays among the highest malpractice premiums of any medical specialty, and experts in the field say it isn't uncommon for lawsuits against obstetricians to allege that more ultrasounds should have been performed.

"You're always afraid you're going to miss something," says Ingrid W. Brown, a physician near Austin, Texas, who says she performed ultrasounds at every maternal visit before discontinuing obstetrics to focus on gynecology. Dr. Brown says she kept scans brief and didn't charge for the majority of them.

Financial Motives

Some experts see financial incentives behind the frequent scans, which can cost up to several hundred dollars each and represent significant revenue for practices. "I suspect that some of this is padding their wallet," says Jeffrey A. Kuller, a Duke University obstetrics professor and practicing doctor.

Parental Demand

Ultrasound has a unique appeal for parents. Offering a magical glimpse inside the womb, it answers one of mankind's oldest questions: "What does my baby look like?"

Many parents long to see their unborn child at every visit. "There was a time or two when it seemed as though she wasn't going to do an ultrasound, so my husband and I requested one, and she obliged," says Tracy Bunye, a 36-year-old New York psychologist who believes regular glimpses of her unborn daughter helped foster bonding.

North Carolina obstetrician Laura Houston describes the reaction when she sticks to the guidelines: "When I say we only need to do as many as are clinically indicated, patients look at me like I'm being mean."

Posting fetal images on social media has become a new rite of parenthood. Ultrasound-equipment maker General Electric even advertises to expecting parents: "Get to Know Your Baby Before It's Born." GE says it markets fetal-ultrasound equipment only to health-care providers for medically necessary scans.

Some parents go beyond their doctors, patronizing nonmedical businesses offering storefront fetal scans. "We offer expectant families the opportunity to bond with their unborn child in a private & peaceful atmosphere with all the comforts of home," says the website of Baby's Premiere 3D/4D Ultrasound Studio LLC in New Jersey. In December 2014, the FDA issued a warning against such "keepsake" or "entertainment" ultrasound providers, advising women to undergo the procedure only for medical reasons.

Key Findings: What the Data Shows About Frequent Scans

The Wall Street Journal's analysis, based on insurance-claim data representing more than 150 million individuals, found the average of 5.2 ultrasounds per delivery included high-risk pregnancies, which require more scans and skew the number higher. But insurance data don't capture all ultrasound use — some physicians perform more scans than they charge for, and keepsake scans at nonmedical shops aren't included at all.

The most important research finding: multiple scans don't appear to produce better outcomes. Consider what major studies have found:

• A 1993 study in the journal Lancet set out to prove the superiority of five fetal ultrasounds over one — but found no benefit to additional scans.
• A 2010 analysis by the Cochrane Collaboration, a medical-research nonprofit, concluded: "Routine scans do not seem to be associated with reductions in adverse outcomes for babies."

Had Ms. Mrosovsky known that more than two scans were unnecessary for her low-risk pregnancy, she says, "I would certainly have asked more questions before blindly following my doctor's lead." Her son is now a healthy 2-year-old.

Safety Concerns: What We Know and What We Don't

Fetal ultrasound in humans has never been shown to cause harm. That's the good news. But there's an important caveat: nearly all research supporting its safety was conducted using equipment made before 1992, when the procedure produced about one-eighth the acoustic energy it is allowed to emit today — and when fetal-ultrasound scanning was far less frequent.

Here's what changed. In 1992, a consortium of physicians and manufacturers persuaded the FDA to raise power limits for fetal ultrasound from 94 to 720 milliwatts per square centimeter — a measurement of acoustic energy and intensity. One reason: with previous constraints, the obesity epidemic was making it difficult to gain clear images of some fetuses. Obstetricians also argued that clearer images would enable more accurate findings.

Since that change, no large epidemiological studies have been performed on the safety of fetal ultrasound at these higher power levels. As a 2012 British Institute of Radiology book, "The Safe Use of Ultrasound in Medical Diagnosis," put it: "No epidemiological or other evidence was then [in 1992], or is now, available to support the assertion of safety at these higher exposures." That book still concluded that the benefits of fetal ultrasound outweigh potential risks — if the procedure is used cautiously.

The US Food and Drug Administration, in its December 2014 warning about keepsake scans, acknowledged the unknowns: "Ultrasound can heat tissues slightly, and in some cases, it can also produce very small bubbles (cavitation) in some tissues. The long-term effects of tissue heating and cavitation are not known."

When the FDA raised power limits in 1992, it required equipment to display two safety indexes:

• A thermal index (TI), which indicates the potential for rising temperature in tissues
• A mechanical index (MI), which indicates the potential for mechanical effects that could pose risks to tissue and cells

Here's the concern: most ultrasound operators pay little attention to these indexes, according to at least four studies published since 2008. A study published in spring 2015 in the Journal of Diagnostic Medical Sonography found that giving operators a "reference tool" didn't help: "Operators in this research study exhibited little knowledge about the TI or MI, and these findings are similar to previous studies on the topic."

Many doctors still assume ultrasound is inherently safe because it doesn't deliver carcinogenic radiation. "They think, 'It's not X-ray. It's safe. Period,'" says Jacques Abramowicz, a Wayne State University obstetrician who chairs the safety committee of the World Federation For Ultrasound in Medicine and Biology. He added that he wasn't aware ultrasound-usage rates were as high as the Journal found.

The American Institute of Ultrasound in Medicine's newly elected president, Harvard obstetrics professor Beryl Benacerraf, says one of her goals is to improve ultrasound training so the safety indexes aren't ignored. "We're trying to rectify that," she says.

False Alarms and Unnecessary C-Sections

Beyond safety unknowns, there's another real-world concern: multiple ultrasounds can raise false alarms. When a scan overestimates fetal size, for example, it can lead to potentially unnecessary cesarean deliveries.

A 2012 paper in the American Journal of Obstetrics and Gynecology found that women who received a fetal-weight estimate via ultrasound within a month of delivery were 44% more likely to be delivered by caesarean section. The paper stated: "Increased use of prenatal ultrasound scanning may be contributing to the rising CD [caesarean delivery] rate."

Unnecessary scans can create a cascade of follow-up testing. "If you go looking for trouble, you will find it," says Duke's Dr. Kuller.

Animal Studies: A Cautionary Note

Some neuroscientists have been studying the effects of ultrasound on fetal animals, with results that warrant attention:

• A 2006 Yale University study published in the Proceedings of the National Academy of Sciences found neurological abnormalities in mice exposed to ultrasound in utero.
• A 2009 study by Australian researchers in the International Journal of Developmental Neuroscience found that fetal chicks exposed to ultrasound in eggs demonstrated post-birth learning and memory deficits.
• A University of Washington study published in 2014 in the journal Autism Research found that mice exposed to ultrasound in utero exhibited hyperactivity and social deficits when around other mice.

In a study funded by the National Institutes of Health, Yale neurobiology chief Dr. Pasko Rakic is subjecting fetal primates to ultrasound to examine their brains after birth for possible neurological abnormalities. These animal findings don't prove harm in humans — but they underscore that the question of long-term safety remains genuinely open.

Clinical Implications: What This Means for Patients

The practical takeaway is straightforward: for a low-risk pregnancy, one or two ultrasounds is sufficient — unless complications or medical concerns arise. The benefits of ultrasound are proven: they provide a more accurate estimate of when conception began, help determine when to induce labor in overdue pregnancies, identify multiple fetuses, and detect abnormalities that elevate pregnancy risk. In high-risk pregnancies, additional scans often are crucial.

Research also suggests that seeing images of the unborn can help foster bonding and may persuade some pregnant women to quit smoking. These are meaningful benefits.

Yet doctors routinely warn pregnant women to avoid alcohol, hot tubs, excessive stress, and other potential risks. There haven't been similar warnings about ultrasound, in part because experts don't want to scare women away from procedures whose medical value far outweighs any potential risks. But now, some fetal-ultrasound experts say women should be explicitly told that — in the absence of complications or alarms — one or two scans are sufficient.

"The message needs to be gotten out," says Phillip J. Bendick, an ultrasound scientist and editor of the Journal of Diagnostic Medical Sonography. "The public needs to be made aware that if you're pregnant, you don't drink alcohol, you don't smoke and you don't need to have an ultrasound at every doctor's visit."

Even the Mayo Clinic updated its website after the Journal asked it to define "routine." Its pregnancy pages previously stated: "Routine fetal ultrasounds are considered safe for both mother and baby." After the inquiry, Mayo's experts "did make some changes to clarify when fetal ultrasounds are appropriate and when they are not."

Limitations: What This Report Couldn't Tell Us

It's important to understand what this reporting could and couldn't establish:

• The FAIR Health data represent insurance claims from more than 150 million individuals, but they don't capture every ultrasound — including scans performed without charge by physicians and keepsake scans at nonmedical businesses. The true usage rate may be even higher than 5.2 per delivery.
• The research on ultrasound safety is based largely on pre-1992 equipment with much lower acoustic energy output. No large epidemiological studies have been conducted on modern equipment since the FDA raised power limits.
• Animal studies showing neurological effects in mice and chicks cannot be directly translated to humans, but they do raise questions that remain unanswered.
• This analysis includes high-risk pregnancies, which legitimately require more ultrasounds — though even looking only at "clearly low risk" populations, the 2013 study found an average of 4.55 scans per pregnancy, still well above the recommended one or two.

Some obstetricians, such as Frank A. Chervenak, chairman of obstetrics at NewYork-Presbyterian Hospital/Weill Cornell Medical Center, believe further research will prove fetal ultrasound harmless. But he still says usage should be once or twice absent medical reasons — "on the chance that there is some unknown association."

Recommendations: Questions to Ask Your Doctor

Here are five things to discuss with your obstetrician about fetal ultrasound scans, based on the experts cited in this article:

1. Is this ultrasound medically necessary? Ask why the scan is being performed and what clinical information it will provide.
2. What if I'm low-risk? If your pregnancy is uncomplicated, remember that one or two scans are the recommended standard.
3. What are the safety indexes? You can ask whether the operator is monitoring the thermal index (TI) and mechanical index (MI) during your scan.
4. Can we keep it brief? The guideline recommends the shortest scan time and lowest acoustic energy needed for an accurate diagnosis.
5. Should I have an elective "keepsake" scan? The FDA advises against ultrasound for nonmedical reasons — entertainment or keepsake purposes — because the long-term effects are not fully known.

No large epidemiological study has found harm from ultrasound in humans, and the medical value of indicated scans far outweighs potential risks. But the experts featured here agree on one thing: in a healthy, low-risk pregnancy, more isn't necessarily better. A dozen photos in a baby album may be lovely, but the medical evidence supports keeping it to one or two carefully performed scans.

Frequently Asked Questions

How many ultrasound scans are recommended during a low-risk pregnancy?

For a low-risk, complication-free pregnancy, medical experts recommend one to two ultrasound scans: one around 12 weeks and one around 20 weeks. About 80% of pregnancies are low-risk. Additional scans are only medically necessary if complications or concerns arise. One or two carefully performed scans are sufficient for healthy pregnancies.

Why are so many pregnant women getting more ultrasounds than recommended?

The rise is due to multiple factors: fear of medical malpractice, financial incentives for practices, parental requests for images, and the appeal of seeing the baby. Some doctors perform scans at every visit. Insurance data show an average of 5.2 ultrasounds per delivery in 2014, a 92% increase from 2004.

Is fetal ultrasound safe for my baby?

Fetal ultrasound has never been shown to cause harm in humans. However, most safety research used equipment from before 1992, which emitted about one-eighth the acoustic energy of today's devices. Modern equipment can heat tissues slightly and create small bubbles, but long-term effects are unknown. No large safety studies have been done at current power levels.

What are the potential risks of having too many ultrasounds?

Beyond unknown long-term effects, excessive scans can lead to false alarms and unnecessary interventions. For example, a 2012 study found women who had a fetal-weight ultrasound within a month of delivery were 44% more likely to have a cesarean section. Unnecessary scans can also trigger a cascade of follow-up testing.

What questions should I ask my doctor before an ultrasound?

Ask: Is this ultrasound medically necessary, and what will it show? If your pregnancy is low-risk, remember one or two scans are standard. Ask whether the operator is monitoring the thermal and mechanical safety indexes. Ask if the scan can be kept brief with the lowest energy needed. Avoid keepsake scans, as the FDA advises against ultrasound for nonmedical reasons.

Should I have a keepsake or entertainment ultrasound?

The FDA advises against ultrasound for nonmedical reasons, such as keepsake or entertainment scans. These are offered by nonmedical businesses and are not included in medical guidelines. The long-term effects of ultrasound at modern power levels are not fully known. For medical purposes, ultrasound benefits can outweigh risks, but for purely bonding or photos, a nonmedical scan is not recommended.

Do more ultrasounds lead to better outcomes for the baby?

No. A 1993 study in the Lancet found no benefit to five ultrasounds versus one. A 2010 Cochrane analysis concluded that routine scans do not seem to reduce adverse outcomes for babies. Even in a clearly low-risk population, a 2013 study found an average of 4.55 scans per pregnancy, which is more than guidelines recommend.

When should a pregnant person with a low-risk pregnancy seek a second opinion about the number of ultrasounds their doctor recommends?

For a low-risk, complication-free pregnancy, medical guidelines call for one or two ultrasounds, with one scan around 20 weeks and an earlier one around 12 weeks. Research shows that in clearly low-risk populations, the average is 4.55 scans per pregnancy, and multiple scans have not been shown to improve outcomes. Modern ultrasound equipment emits more acoustic energy than pre-1992 devices, and long-term effects at these higher levels remain unknown. If your doctor recommends frequent scans, ask whether each is medically necessary and whether safety indexes are monitored. Diagnostic Detectives Network provides independent expert second opinions.

Source Information

This patient-friendly article is based on peer-reviewed research and reporting from the following original source:

• Original title: "Pregnant Women Get More Ultrasounds, Without Clear Medical Need"
• Author: Kevin Helliker (with Rob Barry)
• Publication: The Wall Street Journal, updated July 17, 2015
• Data source: FAIR Health Inc., a nonprofit aggregator of insurance claims representing more than 150 million individuals
• Note: This patient-friendly article is based on peer-reviewed research and investigative journalism. It is provided for informational purposes and is not a substitute for professional medical advice. Always discuss your individual pregnancy care plan with your healthcare provider.