Answer to Question #12180 Submitted to "Ask the Experts"

Category: Pregnancy and Radiation — Power lines, magnets, computers, airport screening, cell phones, radar

The following question was answered by an expert in the appropriate field:


Have any studies been done on wearing an Apple Watch during pregnancy and the potential impact on the baby such as birth defects, etc?


To my knowledge, nobody has tested smartwatches for possible health effects from the radiofrequency (RF) signals that they emit. Doing such tests, even with animals, would be very expensive and time consuming. They would also be very difficult to do in any meaningful way because of the difficulty of controlling exposure. The many studies that have been done in search of possible health effects from cell phones have used specialized equipment—not cell phones themselves—to produce the exposures.

Instead, regulatory agencies—for example, the US Federal Communications Commission (FCC)—require smartwatches and all other devices that emit RF energy to be tested to verify that they meet US safety limits. The tests measure the specific absorption rate (SAR), in a manner similar to that used for cell phone handsets. I looked up the FCC test data for the Apple Watch Series 3. The device has two low-powered radios built into it, one for Wi-Fi and one for Bluetooth. Both transmitters meet US SAR limits by a very large factor, and the SAR test results are far below those from cellular phones.

RF exposure limits in the United States are similar to major international safety limits. They are designed to protect against all known adverse effects of RF energy.

There have been many tests over the years using RF energy at the same frequency, 2.45 gigahertz (GHz or billion cycles per second), at which the Apple Watch operates. Overexposure to RF energy is known to cause birth defects in animals but only at very high exposure levels—levels that are sufficient to raise the temperature of a fetus by several degrees. Such exposures would far exceed safety limits and far exceed anything possible from a smartwatch, cell phone handset, or other consumer electronic product.

I am personally more concerned about the potential of smartwatches for distracting drivers. Talking on a cell phone while driving is known to increase the risk of a car accident, and I would guess that reading email on a smartwatch would have the same effect.

Kenneth R. Foster, PhD
Professor of Bioengineering
University of Pennsylvania

Ask the Experts is posting answers using only SI (the International System of Units) in accordance with international practice. To convert these to traditional units we have prepared a conversion table. You can also view a diagram to help put the radiation information presented in this question and answer in perspective. Explanations of radiation terms can be found here.
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