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Best Motion-Detection Monitors

By: Tara Tuckwiller on March 26, 2018

Motion detection monitors offer an extra layer of monitoring

Most parents have spent at least a few anxious moments hovering over cribs to make sure their baby is still breathing. Motion detection monitors aim to ease this anxiety by sounding an alarm if they don't detect movement in a specified time period. While some have sensor pads that go under the crib mattress, others are designed to be worn by the baby. Parents considering this type of monitor should note that they can be a double-edged sword: Experts say they may give parents a false sense of security, and users will almost certainly have to deal with false alarms.

The Snuza Hero SE (Est. $110), which clips onto baby's diaper, earns the highest praise from owners. If motion isn't detected after 15 seconds, the Hero vibrates to rouse the baby and encourage breathing. If motion isn't detected after 20 seconds, it sounds an alarm. Parents say there are few false alarms, but they do occur, often when the monitor falls off baby's diaper – more often the case for older babies who are more mobile, Baby Gear Lab testers note. Both the vibration and alarm can wake a sleeping baby. Users say that the alarm is loud and clear. Its placement inside baby's clothing eliminates interference from fans, crib mobiles and ambient movements that can affect other motion monitors.

The compact Hero can be positioned at the tummy or on the baby's side. Most say positioning the Hero is easy, but parents of very small infants report fit problems. Others find that they have to adjust diapers to ensure the Hero stays in place. Parents of tummy sleepers may have to opt for side positioning, which some say makes the Hero less sensitive to subtle, deep-sleep breathing. Parents also run the risk of waking a sleeping baby while putting on the monitor. The Hero uses a replaceable CR2 lithium battery, and parents give mixed reports on battery life: Some say they've gone months without replacing the battery, while others say they needed to change it after a couple weeks.

Unlike monitors that use sensor pads under a crib mattress, the Hero can be used anywhere baby sleeps. It is compact and wireless, making it a good choice for families who co-sleep or want to monitor babies on the go. Parents of twins or multiples point out that sensor pads can't be used for more than one baby sharing a sleep space. By contrast, the Hero offers isolated monitoring of the baby wearing it, making multiple units a viable way to monitor more than one baby in the same space. Still, parents who want extras such as nightlights and music will want to look at more traditional monitors.

Some wearable baby monitors don't just track your baby's breathing. The Owlet Smart Sock 2 (Est. $300) actually monitors your baby's heart rate and blood oxygen levels.

The fabric sock contains a wireless pulse oximeter. It beams your baby's vital signs via Bluetooth to a base station, which glows green to let you know everything's OK; the base station blinks red and sounds an alarm if the baby's heart rate or blood oxygen fall below preset limits. It also pushes the info to your smartphone.

Owlet's website publishes dozens of parent testimonials, saying that the Owlet alerted them to serious health problems with their babies. Hundreds of owners rave about the Owlet on retail websites such as Target.com.

However, others warn that this and similar "smart" monitors can lead to a false sense of security or, at the other extreme, cause needless anxiety. Among those, the American Academy of Pediatrics recommends against using these "smart" baby monitors.

"The AAP's main concern is that there's no evidence the devices even work," Dr. Rachel Moon, who chairs the academy's task force on Sudden Infant Death Syndrome (SIDS), tells WebMD. Even FDA-approved, doctor-prescribed cardiorespiratory monitors have not been shown to save babies from SIDS. ("Smart" baby monitors such as the Owlet are not FDA-approved as medical devices.)

AAP also worries that parents might rely too much on the "smart" baby monitor and ignore safe sleep guidelines that are proven to prevent SIDS deaths. "We're worried people will become complacent," Moon said. "If they have a monitor they might feel they can put their baby on its belly to sleep, or sleep with their baby."

Dr. Christopher Bonafide of the Children's Hospital of Philadelpha points out that healthy infants can have sudden drops in their blood oxygen levels, even if there's nothing wrong. "They're just normal fluctuations," he says, but they would set off the Owlet and prompt a parent to bring her baby to the emergency room – exposing the baby to unnecessary germs, medical tests with possible side effects, and causing sleepless, anxious nights for the already sleep-deprived parents.

In fact, that's what happened one night when a woman brought her perfectly healthy infant to Bonafide's hospital after her "smart" alarm kept going off -- prompting Bonafide and others to author an editorial in the Journal of the American Medical Association, cautioning parents to think twice before using these high-tech baby monitors.

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