Is a phone safe by the crib?

Every phone sends and receives radio waves, and a nursery phone does it all night. Here is where the research stands:

• The FDA says the weight of scientific evidence has not linked cell phone radio frequency radiation with any health problems, and that the evidence doesn’t show a danger to users, children and teenagers included.
• The World Health Organization: “no adverse health effect has been causally linked with exposure to wireless technologies.”
• A 2024 review commissioned by the WHO pooled 63 studies from 22 countries and found moderate-certainty evidence that using a mobile phone likely doesn’t raise the risk of brain tumours, in adults or in children.
• In 2011 the WHO’s cancer agency (IARC) classed radio waves as “possibly carcinogenic” (Group 2B), based on limited evidence of a link between wireless phone use and glioma, a type of brain tumour. That label means, in its words, “there could be some risk”, and that the link should be watched.

Almost all of that research is about phones held against the head for calls. A phone on a shelf across the room is a much smaller exposure, as the next section shows.

Switzerland’s Federal Office of Public Health has a fact sheet on baby monitors that covers phones used as one. Radiation levels “decrease very rapidly with increasing distance,” it says; a phone used as a baby monitor a metre from the child is below the limit values, and based on current knowledge baby monitor radiation “is not expected to be harmful to health.” It also says the long-term effects of this kind of low-level radiation are unknown, and that keeping the monitor at a distance is how to keep exposure low.

Its advice:

• Put the baby unit at least one metre from the cot.
• Keep the power adapter at least 50 cm from the cot.

The UK Health Security Agency makes the same point about phones in general: moving a phone away from the body gives very much lower exposure than holding it to the head. In the US, every phone sold has to stay under the FCC’s exposure limit of 1.6 watts per kilogram, and most of the time a phone runs well below the power it’s tested at.

This is the part to take seriously. A nursery phone streams all night, so it needs to stay on its charger, and fire services advise against exactly that: the London Fire Brigade says it’s best not to leave a phone plugged in overnight, and the US National Fire Protection Association (NFPA) says not to keep charging a device once it’s full. Lithium-ion batteries rarely fail, but a small number are faulty and can overheat or catch fire, the NFPA says.

If you use a phone as a monitor, you’re choosing to charge it overnight, so stack the odds:

• Use the charger that came with the phone, or a genuine replacement from a seller you trust (London Fire Brigade, NFPA).
• Charge it on a hard, flat surface where heat can escape: never on a bed, a sofa, bedding or under a pillow, and never covered (NFPA, London Fire Brigade).
• Keep it at room temperature, out of direct sun and away from radiators, and away from anything that can catch fire (NFPA).
• Use the phone’s battery protection if it has one: many phones can stop charging at around 80% or hold off until the battery is needed.

Stop using the phone if the battery shows any of the NFPA’s warning signs: a smell, a change in colour, too much heat, a change in shape, leaking, or odd noises. If it’s safe to, move it away from anything that can catch fire.

A swelling battery often shows as a bulging back or a screen lifting at the edge. The London Fire Brigade says to stop charging straight away, turn the device off, don’t open the casing, and contact the manufacturer or a qualified repairer. A spare phone that has sat in a drawer for a while is worth a look before its first night.

This one isn’t theoretical. Baby monitor cords strangled seven infants and toddlers between 2002 and 2012, the US Consumer Product Safety Commission (CPSC) reported, aged 6 to 20 months, and three more nearly strangled. The monitors and their cords had been placed within reach.

• Keep cords at least three feet from any part of the crib, bassinet or play yard (CPSC).
• Never put a monitor, or a phone, inside or on the edge of the crib (CPSC).
• Keep the sleep space clear of dangling cords and wires, and keep nothing in the crib but a fitted sheet (AAP).

Three feet is about the width of a crib plus six inches. One metre clears both the CPSC’s rule and the Swiss distance for radio waves.

1. Place the phone on a shelf or dresser at least one metre, about three feet, from any part of the cot, on a stand, pointed at the cot.
2. Run the cable away from the cot, so no part of it is within three feet or within reach.
3. Plug in its own charger at the wall, with the adapter at least 50 cm from the cot.
4. Leave it uncovered on a hard surface, out of direct sun and away from radiators.
5. Turn on battery protection if your phone has it.
6. Check it now and then. Warm is normal; hot, swollen or smelly is not.

The settings that keep the phone awake and the stream steady are in the nursery phone checklist, and the reasons behind each placement rule are in where to put a baby monitor.