What is being looked for

The NHS defines it: "Developmental dysplasia of the hip (DDH) is where your baby's hip joint is loose and can move out of its normal position easily." In a normally formed hip the ball at the top of the thigh bone sits deep in a socket in the pelvis. In DDH the socket is shallow or the ball sits loosely in it, so the joint can slip.

The reason it is screened for rather than waited for is in the next line: "Developmental dysplasia of the hip is not usually painful, so many parents do not realise their baby has it." There is no crying, no obvious distress and often nothing to see. The NHS says DDH "is often found during the newborn physical examination", which is exactly why that examination includes the specific hip manoeuvres it does.

NICE's postnatal care guideline NG194 names them: the complete examination of the baby within 72 hours of birth, and again at six to eight weeks, includes checking the "hips: symmetry of the limbs, Barlow and Ortolani's manoeuvres". Those are the two gentle movements a clinician performs to see whether a hip can be pushed out of, or lifted back into, the socket.

Is a click a problem?

Usually not. Newborn joints produce clicks and pops all the time — ligaments and tendons moving over bone in a very loose, very small body. Most clicks heard during nappy changes are not hips dislocating.

But a click is on the NHS's list of things worth mentioning, because when DDH is missed early it can show up later as exactly that. The NHS's symptoms list, for a baby whose DDH was not picked up:

A clicking or popping sound when they move their hips.
One leg moving differently to the other during things like play and nappy changes.
Legs that are different lengths.
Dragging one leg when crawling, or limping when they start walking.

The second and third of those are the more meaningful ones. Asymmetry — one hip that will not open as wide as the other during a nappy change, or an obvious difference in leg length or thigh creases — is a stronger signal than a noise.

Who is more likely to have it

The NHS lists three factors that raise the chance:

Being a girl.
A family history — someone else in the family has had it.
Breech position during pregnancy, lying with the feet upwards, including if you had treatment to turn your baby before birth.

The NHS adds that scanning may be recommended if your baby is more likely to have DDH even when they have no symptoms — which is why some parents are sent for a hip ultrasound after an entirely normal examination. That is screening, not a finding.

How it is diagnosed

The NHS: if a healthcare professional thinks your baby has DDH they will refer you to an orthopaedic surgeon, and DDH is diagnosed in babies using an ultrasound scan of the hip. X-rays are used for older children and adults, because older bones show up more clearly on X-ray than on ultrasound. In a young baby the hip is still largely cartilage, which ultrasound sees and X-ray does not.

Treatment: the harness

The NHS says DDH "can sometimes get better by itself, but most babies need treatment", and describes what that means:

The usual treatment is a soft fabric harness, called a Pavlik harness, that gently guides the hip joint into the right position.
It is fitted by a healthcare professional and worn for six to twelve weeks, depending on severity.
It is left on during nappy changes and bathing, and the hospital will show you how.
Babies "can be restless after the harness is fitted, but most get used to it after 2 to 3 days".
Your baby will have several scans to check the treatment is working, and the harness is adjusted as they grow.

The NHS's framing at the top of its page is the one to hold on to: "Treatment usually works well to correct the problem with your baby's hip." The AAP's guidance on hip dysplasia agrees that treatment started early in infancy is generally successful, and that the point of early detection is to avoid the more involved treatment needed later.

Carrying and swaddling

Hips develop best when they can sit in a flexed, spread position rather than being held straight and pressed together. That is why paediatric guidance advises against swaddling that straps a baby's legs straight, and why slings and carriers should support the thighs so the legs can fall into an M-shape rather than dangling from the crotch. If your baby is in a harness, follow the clinic's instructions over any general advice.

The appointments where this gets checked

Hips are checked more than once, and this is deliberate, because DDH can develop or become detectable after birth. The NHS's newborn physical examination happens in the first 72 hours and is repeated at six to eight weeks. The NHS also notes that hips continue to be looked at during routine health and development reviews, and the HSE's schedule of health and development checks in the first six months covers the same ground for babies in Ireland.

If you have a family history or your baby was breech and nobody has mentioned a scan, ask. It is a reasonable question and the referral criteria are not always obvious to parents.

When to call

Speak to your midwife, health visitor, public health nurse or GP if:

One hip does not open as wide as the other when you change a nappy.
One leg looks shorter, or the skin creases on the thighs or buttocks are not symmetrical.
You hear or feel a clunk rather than a click, especially with one particular movement.
Your baby was breech, or there is a family history of hip dysplasia, and no scan has been arranged.
Your baby drags one leg when crawling, or limps when they start walking.
Your baby seems to be in pain when their hip is moved — DDH is usually painless, so pain is a reason to be seen rather than reassured.

Call your local emergency number (999 in the UK and Ireland, 911 in the US and Canada, 000 in Australia, 111 in New Zealand) if your baby: has a temperature of 38C (100.4F) or above or below 36C (96.8F); looks pale, ashen, mottled or blue; is unresponsive or unrousable; has a weak, abnormally high-pitched or continuous cry; is grunting or breathing over 60 breaths a minute; has a bulging fontanelle, neck stiffness or a seizure; or has a rash that does not fade under a pressed glass. Those are NICE's red flags for serious illness in young babies.

What to let go of

Most clicks are noise. But because DDH is painless and invisible, the noise is worth reporting rather than dismissing — the cost of asking is a five-minute examination, and the cost of missing it, in the NHS's own words, is problems that may not appear until late childhood or adulthood. Double nappies, hip-widening pads and other home remedies are not recommended treatments; the harness is, and it works.

Clicky Hips in a Newborn