Are baby carriers safe for my baby's hips?

The verdict

Carrying a baby in a sling or carrier is not a hip problem when the hips are positioned properly, and the positioning that protects hips is the position babies naturally adopt anyway: knees higher than the bottom, thighs supported, legs bent and spread rather than hanging straight down.

What is genuinely worth your attention is the airway. That is where the recorded harms are, and it is where every UK and US authority puts its emphasis. The Lullaby Trust states that although there is no reliable evidence that slings are directly associated with SIDS, there have been a number of accidents worldwide where infants have died while being carried in a sling, particularly in young infants, and that the risk of these accidents happening appears to be greatest when a baby's airway is blocked, either because their chin is resting on their chest or their mouth and nose are covered by the parent's skin or clothes.

The hip question, answered properly

Hip dysplasia, formally developmental dysplasia of the hip, is described by the AAP as a condition in which a child's upper thighbone is dislocated from the hip socket, which can be present at birth or develop during a child's first year of life. The AAP lists the risk factors as family history, breech birth position, and birth order, with firstborn children most at risk. Carriers do not appear on that list.

What does appear in AAP guidance is tight wrapping of the legs. Its swaddling advice states that babies who are swaddled too tightly may develop a problem with their hips, and that studies have found that straightening and tightly wrapping a baby's legs can lead to hip dislocation or hip dysplasia. Its recommendation, developed with the Pediatric Orthopaedic Society of North America and the AAP Section on Orthopaedics, is hip-healthy swaddling that allows the baby's legs to bend up and out, with the practical test being that you should be able to get at least two or three fingers between the baby's chest and the swaddle.

That is the actual mechanism, and it applies to any device that holds the legs extended and pressed together. A well-fitted carrier does the opposite: it supports the thigh from knee to knee so the hip sits flexed and abducted, which is the position that keeps the femoral head seated in the socket.

The AAP's own carrier guidance approaches this from the fit side: take your baby with you when you shop for the carrier so you can match it to their size, and make sure the carrier supports their back and the leg holes are small enough that they can't possibly slip through.

What a badly fitting carrier looks like

A carrier where the baby's weight hangs from a narrow crotch strap, with the legs dangling straight down and the thighs unsupported, is the configuration to avoid. It is uncomfortable, it loads the spine rather than the hips and thighs, and it is the design that gives carriers their reputation. Adjust the panel width so the fabric reaches from the back of one knee to the other.

Your pediatrician or GP checks hips at every well-child appointment. The AAP notes that a pediatrician will check a newborn for hip dysplasia right after birth and at every well-child exam until the child is walking normally, flexing and rotating the legs to see if the thighbones are properly positioned. If you have any concern about clicking, uneven skin creases or asymmetric leg movement, raise it there.

The airway rules, which matter more

The UK acronym is TICKS, from the Consortium of UK Sling Manufacturers and Retailers, and it is reproduced by both the Lullaby Trust and the NHS:

• Tight. Slings and carriers should be kept tight enough to hug your baby close to your body.
• In view at all times.
• Close enough to kiss their head.
• Keep chin off the chest.
• Supported back.

The Lullaby Trust's framing is that these guidelines help you make sure your baby can breathe easily and is not overheating.

The AAP adds detail on why the C-shape is the danger: some sling carriers may curl your baby's body into a C-shape, which greatly increases the risk of breathing problems. If you use a sling, your baby's neck should be straight and their chin not pressed into their chest, and you should always be able to see their face. In any type of carrier, check on your baby frequently and make sure that their mouth and nose are not blocked by fabric or your body, and that airflow is not restricted.

The AAP notes that the Consumer Product Safety Commission warns about the suffocation hazard to infants, particularly those younger than 4 months, carried in infant sling carriers. Its sling checklist is: the baby's head is up and above the fabric, their face is visible, and their nose and mouth are clear of anything that could block airflow.

Do not feed hands-free

The Lullaby Trust is explicit and the NHS repeats it. Hands-free breastfeeding or bottle feeding, where the wearer moves around and does other jobs while the baby is feeding, is unsafe. This is especially true for babies under four months old, and also applies to babies born prematurely or those with a health condition. Moving around with loose sling fabric could also be a trip hazard. If the baby needs to feed, take them out of the sling; when they have finished, either return them to the sling or put the baby down in a safe space.

The NHS puts it in six words: it's not safe to feed your baby while they are in a sling.

Who should be extra careful

The AAP states that infants born prematurely or with respiratory problems should not be placed in backpacks or other upright positioning devices, as the positioning in these devices may make it harder for them to breathe.

How long is too long

Slings are not the concern here; reclining seats are. The NHS advises that long periods in reclining carriers or seats, or seats that prop your baby in a sitting position, can delay your baby's ability to sit up on their own, and that if you do use a baby walker, bouncer or seat, it's best to use them for no more than 20 minutes at a time.

An upright, well-fitted sling with a baby held against your body is a different proposition from a semi-reclined bucket seat, and none of the guidance sets a time limit on the former.

Where guidance differs

Not much, on advice. Considerably, on regulation.

The US has mandatory federal standards; the UK does not. The CPSC codifies sling carriers at 16 C.F.R. part 1228, incorporating ASTM F2907, published at 82 FR 8671, defining a sling carrier as a product designed to contain up to two occupant children, with a child defined as between full-term birth and 35 lbs, which is 15.9 kg, in an upright or reclined position while being supported by the caregiver's torso. Soft infant and toddler carriers are separately regulated at 16 C.F.R. part 1226, incorporating ASTM F2236. The requirements cover structural integrity, restraint systems, openings, warning labels sewn to the fabric, and flammability. UK carriers are covered by general product safety law and voluntary standards rather than an equivalent mandatory regime.

The UK has an acronym; the US has a checklist. TICKS is a UK industry consortium product carried by the Lullaby Trust and the NHS. US advice makes the same points without the mnemonic.

Nobody publishes a hip-position rule. The AAP's hip-healthy language attaches to swaddling, not carriers. No national authority in these countries publishes a carrier hip standard, which is why this page describes the mechanism rather than quoting a rule.