Is an early ultrasound safe for the baby?

What the FDA and medical societies say

No harm to a baby from diagnostic ultrasound has been proven. Safety bodies still ask for care: a reason for every scan, and the lowest exposure that does the job.

• The FDA. Ultrasound “has an excellent safety record.” But it “can heat the tissues slightly,” and “the long-term consequences of these effects are still unknown” (FDA).
• ACOG. Ultrasound and MRI “are not associated with risk and are the imaging techniques of choice for the pregnant patient.” ACOG adds that they should be used “prudently and only when use is expected to answer a relevant clinical question or otherwise provide medical benefit to the patient” (ACOG Committee Opinion 723).
• The AIUM. The American Institute of Ultrasound in Medicine finds “insufficient justification” to conclude that diagnostic ultrasound causes recognized harm in humans. It asks for “a conservative approach that obtains necessary diagnostic information at minimal exposure” (AIUM).
• WFUMB and ISUOG. That’s the World Federation for Ultrasound in Medicine and Biology, writing with the International Society of Ultrasound in Obstetrics and Gynecology. Their 2015 statement on souvenir images says there have been “no reported incidents of human fetal harm in over 40 years” of medically indicated, supervised use. But ultrasound has “the potential to initiate biological effects,” and some “might, under certain circumstances, be detrimental” to a developing baby. So “the uncontrolled use of ultrasound without medical benefit should be avoided” (WFUMB/ISUOG, 2015).
• BMUS (UK). “There is no evidence that diagnostic ultrasound has ever produced any harm to adults, children or the human foetus and embryo.” But “laboratory tests have shown that ultrasound can cause heating and other potentially harmful effects inside the human body if used at inappropriate power levels or for prolonged periods” (British Medical Ultrasound Society).
• The NHS (England). “There are no known risks to the baby or the mother from having an ultrasound scan” (NHS).

…the absence of conclusive studies demonstrating causal relationships does not constitute proof that adverse effects are impossible.

American Institute of Ultrasound in Medicine, 2020

How ultrasound could affect tissue

Ultrasound uses sound, not X-rays: the FDA says it “is based on non-ionizing radiation.” But it puts energy into the body, and the FDA says that in laboratory studies, diagnostic levels can have physical effects on tissue, such as these (FDA):

The two safety numbers on the screen

ISUOG says two safety estimates “should be displayed on the ultrasound screen” (ISUOG, 2021).

• TI, the thermal index, compares the probe’s power with the power needed to warm tissue by 1°C under model conditions. It’s an estimate of possible heating, not a thermometer reading (Health Canada). Up to 10 weeks, counted from your last period, the soft-tissue version (TIS) applies. After that, once the beam can meet bone, the bone version (TIB) does (BMUS).
• MI, the mechanical index, shows “the relative potential for ultrasound to induce an adverse bio effect by a non thermal mechanism such as cavitation,” BMUS says. It should be kept “as low as reasonably achievable.”

ALARA, in numbers

ALARA, short for “as low as reasonably achievable,” means the lowest output and the shortest scan time that still get the needed medical information, BMUS says. In its section on Doppler at 11 to 14 weeks or earlier, the AIUM says “All scans should begin at a displayed TI of 0.7” (AIUM).

Its limits for obstetric scans tie the TI to “dwell time,” how long one spot stays in the beam without a break. At a TI of 0.7 or below, there’s no time limit. Up to 1.0, it’s under 60 minutes, shrinking to under 1 minute between 2.5 and 3.0. Above 3.0, scanning is “not recommended” (AIUM). The AIUM adds that “the principle of ALARA should be followed so that examination times are only as long as necessary to produce a useful diagnostic result.” It strongly discourages scans done only for keepsakes.

Why the earliest weeks get extra care

The guidance singles out early pregnancy. BMUS says potential effects “are likely to be of greatest significance in the embryo or fetus,” and its chart of scanning times labels its recommended range “(especially in 1st trimester).” ISUOG stresses avoiding “unduly harmful ultrasound energy, particularly in the earliest stages of pregnancy.” Neither reports a known harm from early scans.

Doppler in the first trimester

Doppler checks movement, such as blood flow, and can let you listen to the heartbeat (RadiologyInfo.org, FDA). It uses more energy than the ordinary black-and-white (B-mode) picture: ISUOG says, “Compared with grayscale imaging, color Doppler increases the total power emitted” (ISUOG, 2021).

• The AIUM says spectral Doppler “should not be used to document the fetal heart rate unless clinically indicated.” For the heart rate, it recommends M-mode or B-mode, with the TI “preferably less than or equal to 0.7.” Pulsed Doppler, it adds, “should not be used routinely” (AIUM).
• WFUMB and ISUOG set a TI of 1.0 or lower for Doppler at 11 to 14 weeks or earlier. Exposure should be “usually no longer than 5-10 minutes” and never over 60 (WFUMB/ISUOG). The AIUM’s version asks for 0.7.

When can you see the heartbeat on an ultrasound? explains seeing versus hearing the heartbeat.

What studies of children have found

Two large reviews pooled the evidence.

• Cochrane, 2015. This review asked whether routine scans before 24 weeks change diagnosis, care and outcomes. Its 11 trials, with 37,505 women, compared routine scans with scans only “for specific indications” or with scans whose results were concealed, so both groups could be scanned. On children, it says: “Long-term follow-up of children exposed to scan in utero does not indicate that scans have a detrimental effect on children’s physical or cognitive development.” Its summary doesn’t say how many children were followed up (Whitworth and colleagues).
• WHO, 2009. A review for the World Health Organization covered 61 publications from 41 studies (16 controlled trials, 13 cohort and 12 case-control studies) of B-mode or Doppler scans at any stage of pregnancy. Ultrasound wasn’t linked to worse outcomes for mothers or for babies around birth, impaired physical or neurological development, childhood cancer, lower intellectual performance or mental illness. In the trials, there was “a weak association” with non-right-handedness (being left- or mixed-handed) in boys, with an odds ratio of 1.26. The authors concluded that “according to the available evidence, exposure to diagnostic ultrasonography during pregnancy appears to be safe” (Torloni and colleagues).

Their limits:

• They aren’t first-trimester studies. “Early” meant before 24 weeks in the Cochrane review, and the WHO review covered any stage.
• Machines have changed. The AIUM says the evidence comes mostly from before 1992, when output limits for pregnancy scans were “substantially increased.”
• Findings were mixed. Some studies reported low birth weight, delayed speech, dyslexia and non-right-handedness, and others didn’t, the AIUM says. It sees no proof that ultrasound causes harm, and no proof that harm is impossible.
• The quality was modest. The Cochrane authors rated the evidence for their main outcomes moderate or low, and said lack of blinding was “a problem common to all studies.”

Can an internal scan cause a miscarriage?

Two NHS hospital trusts in England say no. Their patient leaflets say an internal (transvaginal) scan poses no risk to the safety of your pregnancy. “There is no increased risk of miscarriage,” they add (Leeds Teaching Hospitals, Cambridge University Hospitals). Internal or belly ultrasound? explains how each scan is done.

Why the worry? About 10% to 20% of known pregnancies end in miscarriage, most because the pregnancy doesn’t develop properly (Mayo Clinic). And the NHS notes that “sometimes you may have no symptoms and you’ll only find out you’ve had a miscarriage at a pregnancy scan” (NHS). A scan can be where a loss is found. That’s different from being its cause.

If you lost a pregnancy after a scan and wondered whether it played a part, the guidance above says internal scans don’t raise the risk. Mayo Clinic says that “most of the time, miscarriage happens because of a random event that is no one’s fault.” The National Maternal Mental Health Hotline is free, confidential and open 24/7, in English and Spanish: call or text 1-833-TLC-MAMA (1-833-852-6262) (HRSA). Pregnant after a loss: seeing your baby early is for the next pregnancy.

Whatever you’ve had done, bleeding or pain needs attention:

In the UK, the NHS says to call 999 if you’re pregnant with vaginal bleeding and any of these: heavy bleeding, severe tummy pain, shoulder pain, or feeling sick, faint or dizzy. For light bleeding or spotting with no or only mild pain, it points you to your maternity unit, an early pregnancy unit or NHS 111 (NHS).

How many ultrasounds are safe?

There’s no set number, and none of the bodies quoted here gives a safe count. Each medical scan is meant to have a reason: ACOG’s test is whether it “is expected to answer a relevant clinical question or otherwise provide medical benefit.”

In the U.S., Cleveland Clinic says most people have two, and a provider may suggest more if a pregnancy is high-risk or a problem is suspected (Cleveland Clinic). Hospitals in England offer at least 2, and “you may be offered more than 2 scans, depending on your health and the pregnancy” (NHS). What to expect at your first pregnancy ultrasound covers the first one.

For keepsake scans, the FDA and AIUM give no number; they discourage scans done only for keepsakes. The FDA says ultrasound is “generally considered to be safe with very low risks,” but the risks “may increase with unnecessary prolonged exposure to ultrasound energy, or when untrained users operate the device” (FDA). Is an early reassurance scan worth it? helps you weigh an extra look.

Keepsake scans and home devices

You should hear this from a keepsake studio before you book: the FDA and the AIUM discourage scans done only for keepsakes. Safety, in plain words quotes their statements. If you have a fever, the AIUM says scans should be done only if clinically indicated, and put off until your temperature is normal, if possible (AIUM).

• The FDA says “the use of ultrasound solely for non-medical purposes such as obtaining fetal ‘keepsake’ videos has been discouraged.” Keepsake images are reasonable, it says, when they come from a medically indicated exam “and if no additional exposure is required” (FDA).
• The AIUM “strongly discourages the nonmedical use of ultrasound.” Using ultrasound without a medical indication to see a baby, take pictures of it or identify its sex “is inappropriate and contrary to responsible medical practice,” it says. Of the places keepsake images come from, it finds only medically indicated exams and teaching programs “consistent with the ethical principles” of the AIUM, the American Medical Association and ACOG. That leaves out “freestanding commercial fetal imaging sites,” a group that includes studios like ours (AIUM).
• Inteleos, which runs the ARDMS sonography credentials, says: “We do not recognize or endorse use of ultrasound for non-diagnostic purposes.” It has adopted the AIUM’s position on keepsake ultrasound (Inteleos).
• BMUS says ultrasound “should not be used on pregnant women solely for ‘entertainment’ or ‘bonding’ purposes” (BMUS).
• WFUMB, in its statement with ISUOG, “disapproves” of using ultrasound only to provide souvenir images of a baby (WFUMB/ISUOG, 2015).

Some places go further. Connecticut law allows an obstetric ultrasound only for a medical or diagnostic purpose, ordered by a licensed provider (AuntMinnie). Germany has banned non-medical ultrasound in pregnancy, 3D and 4D included, since January 1, 2021 (Deutsches Ärzteblatt). Can you get a pregnancy ultrasound without a doctor’s referral? covers where elective scans are allowed.

Home Dopplers and home scanners

Home heartbeat monitors, or fetal Dopplers, are sold over the counter, but the FDA says they “should only be used by trained health care providers when medically necessary.” Untrained use, it warns, could expose a baby to “prolonged and unsafe energy levels” or be misread (FDA). The NHS advises against them: “Even if you hear a heartbeat, this does not mean your baby is well” (NHS).

Home ultrasound scanners raise the same worries. Two UK professional bodies warned in 2020 that untrained home scanning “could provide false reassurance” and “can result in much longer exposures” (SCoR and BMUS). In the U.S., the FDA authorized one home pregnancy ultrasound system in October 2025. It’s a prescription device for checking the heart rate of one baby at 14 to 38 weeks, ordered for a medical reason, with a physician reading the images remotely (FDA). If you’re worried about your pregnancy, call your doctor or midwife rather than checking at home.

Where we stand, as a keepsake studio

We’re a keepsake studio in Glendale, Los Angeles County, so this article is partly about us. The FDA and the AIUM discourage what we do, and we won’t tell you the experts are wrong. Safety, in plain words quotes them and sets out how we work, knowing that.

Our Pregnancy Check is a short, private 2D ultrasound in the first 10 weeks, and it takes a few minutes. It’s a keepsake, not a health check: we don’t screen or diagnose, and we’ll never tell you that everything is fine. You take home 8 black-and-white prints, for $100.

Whether to have a keepsake scan is your decision, and it’s worth talking over with your doctor or midwife. Keep every appointment and every scan they order; ours replaces none of them. If you have any worry about your pregnancy, call them, not us. If you decide to come, call (818) 243-7010 first and tell us the first day of your last period. How the Pregnancy Check works.

Give the planner a due date, even an approximate one, and it lists the sessions you could book now and the ones that open next. Your entries stay on your device.

Questions