Be extra careful with medical devices, such as pacemakers and defibrillators, if you own an iPhone 12 and use MagSafe accessories, Apple warns.

In an addition to its support document for the latest iPhones, Apple says that the iPhone and MagSafe accessories, including the MagSafe Charger and MagSafe Duo Charger, should be kept away from implantable medical devices so as not to cause any potential issues. The support document addition was first noted by MacRumors.

Interfering With Medical Devices

Apple writes that, "iPhone contains magnets as well as components and radios that emit electromagnetic fields. All MagSafe accessories (each sold separately) also contain magnets---and MagSafe Charger and MagSafe Duo Charger contain radios. These magnets and electromagnetic fields might interfere with medical devices."

Apple recommends keeping them more than six inches apart at all times, and more than 12 inches when wirelessly charging. It continues by saying:

Medical devices such as implanted pacemakers and defibrillators might contain sensors that respond to magnets and radios when in close contact. To avoid any potential interactions with these devices, keep your iPhone and MagSafe accessories a safe distance away from your device … [C]onsult with your physician and your device manufacturer for specific guidelines.

Related: The Next MacBook Air Will Be Thinner, Lighter, and Revive MagSafe

Apple does, however, suggest that, while the MagSafe-equipped iPhone 12 models do feature more magnets than previous iPhones, they are "not expected to pose a greater risk of magnetic interference to medical devices than prior [iPhones.]"

That makes it sound as if it's the devices like Apple's MagSafe chargers that are the main potential risk factor---although, as Apple suggests, it might be worth seeking out some expert advice from your physician and the manufacturer of any medical device you happen to use, just to be on the safe side.

MagSafe on the iPhone

Recently, an article in the publication Heart Rhythm Journal claimed that the iPhone 12 could "potentially inhibit lifesaving therapy in a patient" as a result of its magnets interfering with implantable medical devices like cardioverter defibrillators.

"Medical device manufacturers and implanting physicians should remain vigilant in making patients aware of this significant interaction of the iPhone 12 and other smart wearables with their cardiac implantable electronic devices," the publication observed.

The MagSafe system was introduced to the iPhone with last year's iPhone 12 series. (It was previously the branding for a neat magnetic charging system for MacBooks, which may be making a return.) The MagSafe iPhone system can be used for charging, as with the two chargers mentioned above. But it can also support non-charger accessories like card holders.