Are Ultrasounds During Pregnancy Safe for Babies?

It's natural to wonder whether ultrasounds during pregnancy might be harmful to your baby. After all, there's a list of things from certain foods to skincare ingredients you're told to avoid when you're pregnant—what about ultrasound waves directed right at your belly? Fortunately, the American College of Obstetricians and Gynecologists (ACOG) states that there is no current evidence that ultrasounds pose any risk to an unborn baby.

"No links have been found between ultrasound and birth defects, childhood cancer, or developmental problems later in life," the ACOG adds. However, the organization also notes that while there is no current evidence that ultrasounds are dangerous to a baby during pregnancy, they also say that it's best to be on the safe side, so they do recommend limiting ultrasounds to only those that are medically necessary.

Here's what else expecting parents should know about the safety of ultrasounds during pregnancy.

How Do Ultrasounds Work?

To understand the safety of ultrasounds, it helps to learn how they work. Ultrasounds send sound waves through the body to get a glimpse at the fetus's tissues and organs. They’re especially useful for observing fetal development, and they can detect abnormalities in the womb—including some that can be addressed before your baby is born.

"There is a much higher likelihood that birth defects of all types will be identified by ultrasound," says Bart Putterman, M.D., an OB-GYN at Texas Children's Pavilion for Women in Houston.

During the 15- to 30-minute procedure, the sonographer (someone trained to do ultrasounds) puts gel on your abdomen, then uses a special wand called a transducer that emits the sound waves to create pictures of your baby on the screen. The waves bounce off of different structures in your body, like tissue, bones, and fluid, to produce an image the sonographer can interpret.

Are Ultrasounds Safe for Babies?

According to both the Food and Drug Administration (FDA) and the American College of Obstetricians and Gynecologists (ACOG), there’s no evidence that ultrasounds harm a developing fetus. The exams don’t use radiation or X-rays, two things that do have known risks.

But there’s also a catch: Scientists aren’t sure if non-medical long-term ultrasound exposure is potentially dangerous. The main concern is that energy from ultrasound waves heats up the tissues in your growing baby, and this might somehow affect them down the road. "ACOG makes it very clear that the energy delivered to the fetus cannot be assumed to be completely safe," says Michele Hakakha, M.D., an OB-GYN in Beverly Hills and author of Expecting 411. "The possibility exists that some ill effects may occur when ultrasound is used inappropriately."

So how many ultrasounds are safe during pregnancy? There’s no clear answer, but despite the very slight possibility of risks, most experts agree that medically necessary ultrasounds are nothing to worry about. But that also means that you should skip any non-medical ultrasounds, such as those from companies that offer "sneak peaks" or advertise finding out your baby's sex.

What About 3D and 4D Ultrasounds?

Some doctors use 3D ultrasounds to provide pictures of the baby with clear, photograph-quality details. Others have 4D ultrasounds with video capabilities, which let you see moving images of your baby in the womb. There are benefits to these types of exams; for example, high-quality imaging can help doctors better diagnose certain defects, says Dr. Hakakha.

Like their traditional two-dimensional counterparts, 3D and 4D ultrasounds are considered safe, as long as they’re conducted by a certified professional based on medical recommendation. Parents shouldn’t get a 3D or 4D ultrasound to simply have a “better look” at their baby’s face, says Dr. Hakakha. They should also avoid commercial shops that offer “keepsake" 3D ultrasound images and 4D videos.

"Ultrasounds should be done only when medical information about pregnancy is needed, and should be done only at the lowest possible setting," says Dr. Hakakha. "Ultrasounds at the mall, administered by a technician of unknown training using a machine of unknown calibration and safety, done for an unknown duration of time in order to get a picture of a fetus' face, may be dangerous."

In fact, the FDA issued a special update urging consumers to avoid these fetal "keepsake" ultrasound images and videos, as well as heartbeat monitors.

The Bottom Line

"Ultrasound has been in use during pregnancy for the past 35 to 40 years, and it has an extremely good safety record," says Dr. Putterman, adding that there's no scientific data that indicates that ultrasound examinations are harmful for pregnant people or developing fetuses.

Still, experts recommend that you have ultrasounds only when medically necessary‚ and that means that you should avoid those commercial ultrasound shops. Only visit a trained professional who can interpret the results with accuracy and detect abnormalities. Your technician should be schooled in obstetrical ultrasound, preferably at a center accredited by the American Institute of Ultrasound in Medicine.

And when in doubt, don't hesitate to talk to a health care provider about any concerns you have or to discuss why they have ordered any ultrasounds during your pregnancy. Your pregnancy care provider is there to ensure the safety of both you and your baby, so it's perfectly acceptable to make sure all your concerns are addressed.