Several UK retailers have stopped selling baby sleep positioners amid fears they can cause babies to suffocate.

The positioners, sometimes called nests or wedges, are intended to keep the baby in one place on their back and are marketed as suitable for use for infants of up to six months of age.

Some parents use them in the hope that their baby will sleep longer as it can make them feel cosy, while others believe they reduced the symptoms of reflux.

But firms including John Lewis and Tesco have removed the products from their websites after US authorities issued a fresh warning to parents, saying they were unsafe.

The US Food and Drug Administration (FDA) has linked the products to at least 12 baby deaths in America, in some of which babies had rolled from their side to their front and suffocated.

John Lewis has removed the Cocoonababy Sleep Positioner from sale but still has a range of “nests” and “pods” available including the Cocoonababy nest and the Sleepyhead.

The retailer told worried customers on Twitter that both of these products were not considered to be sleep positioners and therefore were still on sale.

“We have one baby sleep positioner and as a precautionary measure we are removing it from sale,” John Lewis said in a statement.

A Tesco spokesman said: “We have removed these products from our website as a precautionary measure.”

Mothercare removed the Babymoov Cosy Dream sleep positioner from sale. Other retailers, however, including Amazon and JoJo Maman Bébé, are still offering them.

A spokeswoman for JoJo Maman Bébé said it was still selling the products but was “investigating the issue as a matter of urgency with our suppliers”.

A spokeswoman for Amazon, which has a range of sleep positioner products for sale, said the firm would not be commenting on the issue.

Several of the products were still available on eBay but a spokeswoman said it was planning to remove them. “Following recent recommendations by US authorities, items of this nature will now be prohibited from being sold on our platform. Our team will be informing sellers and removing any listings that contravene our policies,” she said.

Manufacturers are still selling the products via their websites. Babymoov said in a statement: “We would like to assure customers that our award-winning, paediatrician-approved Cosydream has never been involved in any incident connected with infant fatality.

“Nor does the Cosydream resemble the products that first gave rise to the FDA guidelines seven years ago … our Cosydream has never been sold in the United States and thus can’t be involved in the incidents [cited by the FDA]. Over 100,000 Cosydream units have been sold to satisfied customers worldwide since the product was first launched four years ago.”

It said the design of the Cosydream “enables babies to sleep safely on their back in accordance with recommendations by the NHS”.

The FDA said it was “reminding parents and caregivers not to put babies in sleep positioners. These products – sometimes also called ‘nests’ or ‘anti-roll’ products – can cause suffocation (a struggle to breathe) that can lead to death.”

The FDA and the NHS recommend that infants sleep on their backs on a flat mattress in an empty crib. The FDA said its safety advice was to “never use infant sleep positioners. Using this type of product to hold an infant on his or her side or back is dangerous”.

It said: “The federal government has received reports about babies who have died from suffocation associated with their sleep positioners. In most of these cases, the babies suffocated after rolling from their sides to their stomachs.

“In addition to reports about deaths, the federal government also has received reports about babies who were placed on their backs or sides in positioners but were later found in other, dangerous positions within or next to these products.”

The Lullaby Trust, a baby charity, said: “There are hundreds of baby sleep products on the market and parents assume that if something is for sale it is safe to use.

“We do not recommend wedges and sleep positioners as evidence shows that the safest way for a baby to sleep is on a firm, flat mattress, in a clear cot free of pillows, toys, bumpers and sleep positioners.”

It added: “Babies are at higher risk of sudden infant death syndrome if they have their heads covered and some items added to a cot may increase the risk of head-covering and can also increase the risk of accidents.

“We recommend that, while evidence on individual products is not widely available, parents do not take any chances and stick to scientifically proven safer sleep guidelines.”