A line of baby-monitoring socks, marketed to measure a baby’s vital signs while they sleep, has been discontinued after a warning letter from the Food and Drug Administration.

Owlet, the maker of Smart Sock, has pulled its product from its website after the Food and Drug Administration issued a warning letter last month stating that the socks are medical devices that Owlet has sold without the FDA’s “marketing approval, clearance, or authorization,” according to the letter.

Owlet said in a statement on its website it plans to “pursue marketing authorization from the FDA for these features.”

The company said it also plans to “work toward the submission of a device application to FDA” to make the Smart Sock a medical device.

“As a result of the letter and in light of our plans to submit a device application to the FDA, we will no longer be selling the Smart Sock,” the company said in the statement. “We plan to offer a new sleep monitoring solution, which we believe will be available soon. We also plan to continue to support our current customers.”

Owlet also specifies on its website that the FDA’s warning letter is not a recall of the product and that no safety issues have been identified.

“There has not been any change to your product’s functionality or a request from the FDA to exchange or return your product at this time,” the statement said. “We will notify customers of any updates to the Smart Sock products that have already been distributed. This action is specific to the U.S. only and no other countries or regions are affected by this.”

The company said it has sold over 1 million Smart Socks, which fit on an infant’s foot.

The American Academy of Pediatrics (AAP) advises against relying on home monitors and other devices that may be marketed to reduce the risk of sudden infant death syndrome, or SIDS.

“Do not rely on home heart or breathing monitors to reduce the risk of SIDS,” the AAP states on its website. “If you have questions about using these monitors for other health conditions, talk with your pediatrician.”

Here are five safe sleep practices for infants recommended by the AAP.

1. Place babies to sleep on their backs, on a firm surface.

2. Avoid use of soft bedding, pillows, crib bumpers or stuffed animals.

3. Co-sleeping is not recommended, but parents should co-share a bedroom with their infant preferably until the baby turns 1, but at least for the first six months. The APA says that room sharing decreases the risk of SIDS “by as much as 50 percent.”

4. Do not place a baby to sleep on a couch , sofa or armchair or on nursing pillows or pillow-like lounging pads.

5. Give your baby a pacifier at nap time and bedtime.