Babywearing
How to choose an ergonomic carrier
What to look for in an ergonomic carrier. Panel width and height, a knee-to-knee seat, carriers from birth, the EN 13209-2 standard, facing out, and adjusting it correctly.
In-depth guide 4 min read
Ergonomic carrying and healthy hips
In babywearing there is a lot of talk about the “froggy” position and “healthy hips”. Here is what the International Hip Dysplasia Institute actually says about it, what is established and what is exaggerated.
What the M position is
When you lift a newborn under the arms, they usually draw up their legs and spread them to the sides, as if trying to cling on. The IHDI describes this as a natural position: the thighs spread around the parent’s body, the hips bent and the knees slightly higher than the bottom, with the thighs supported.1 Seen from the side it resembles the letter M, hence the M position (also called the “froggy” or “spread-squat” position).
Why the first six months
According to the IHDI, the hips develop fastest up to six months and then more slowly until the age of one.1 When the hip is in the M position, the head of the thigh bone is pressed evenly into the socket. That is why the Institute recommends carrying facing the parent for the first six months, where the M position is easiest to maintain.1
What is established and what isn’t
The Institute is careful in what it says, and it is worth drawing the distinctions:
| Claim | What the IHDI says |
|---|---|
| The M position is healthy for the hips | yes, it recommends it; there is epidemiological evidence that it may reduce the risk of persistent dysplasia3 |
| A narrow seat causes dysplasia | there is no evidence that it causes it in otherwise healthy hips3 |
| A narrow seat is fine for long carries | it does not recommend it; the forces on the hip may not suit a loose joint2 |
| Legs straightened and pressed together are harmful | yes, this is the only position for which there is evidence of harm, for example in tight swaddling2,3 |
| A wide seat holds the hips better than a narrow one | a 2023 ultrasound study confirmed this4 |
The IHDI also gives figures: about one in ten newborns has a mildly unstable hip and about one in a hundred needs treatment.3 Carrying in the M position is therefore a sensible habit, not a cure. If your baby has been diagnosed with hip dysplasia or wears a brace, talk to an orthopaedic specialist about carrying.
How to check the M position
- Look from the side. The knees are slightly higher than the bottom.
- Run your hand under the thighs. The fabric or panel reaches right to the hollows behind the knees.
- Look from behind. The bottom sits deep in the seat, the pelvis is tilted slightly forward, the back is in its natural curve.
- Don’t force the legs apart. For small babies, less spread and more bend is healthier; as they grow, the opposite.1
Swaddling and the hips
The same principle applies beyond babywearing. When swaddling, The Lullaby Trust advises leaving looser room around the hips so the legs can move naturally, because swaddling too tightly can lead to hip problems.5
The M position in different slings and carriers
| Sling or carrier | How to achieve the M position |
|---|---|
| Wrap | spread the seat from knee to knee, with the bottom edge of the fabric in the hollows behind the knees |
| Ring sling | as with a wrap; tighten the bottom edge too |
| Ergonomic carrier | adjust the panel width for the child’s age; belt higher, so the child sits deep |
| Hip seat | difficult with small babies; the IHDI points out that in seats and when facing out the M position is harder to maintain6 |
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Frequently asked questions
Will a carrier with a narrow seat cause hip dysplasia?
The IHDI says there is no evidence that a narrow seat causes dysplasia in otherwise healthy hips. At the same time, it does not recommend a narrow seat for long carries, because it does not support natural development, and it may be unsuitable for babies with loose hips.
Until when does the M position matter?
The IHDI considers it most important in the first six months, when the hips develop fastest. After that development slows, but well-supported thighs are comfortable for an older child too.
Where this comes from
The numbers in the text refer to these sources. The links go to the publishers’ own pages; we simply cite them.
- International Hip Dysplasia Institute:Baby Wearing
- International Hip Dysplasia Institute:Baby Carriers & Other Equipment
- International Hip Dysplasia Institute:Benefits of the spread-squat position for baby carryingAbout one in ten newborns has a mildly unstable hip and about one in a hundred needs treatment; there is no evidence that carrying in another position causes dysplasia in healthy hips.
- International Hip Dysplasia Institute:Babywearing research confirms hip-healthy position in wide-base carriers (2023)
- The Lullaby Trust:Safer sleep awareness (booklet)When swaddling, leave looser room around the hips for hip development.
- International Hip Dysplasia Institute:Infant Carrier Design Considerations – Criteria for Hip-Healthy Designation
We last checked these sources on 13 October 2026.
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