Hip Health in baby
carriers, car seats, swings, walkers, and other equipment
Summary Statement: The Medical Advisory Board of the
IHDI does not endorse nor advise against any particular baby carrier or
other equipment. The purpose of this educational statement is to provide
information about healthy hip development to guide manufacturers in the
development of safe designs of infant equipment, and to help parents
make informed choices about the devices they use for their babies.
Parents and caregivers are encouraged to choose a baby carrier that
allows healthy hip positioning, in addition to other safety
considerations. When babies are carried, the hips should be allowed to
spread apart with the thighs supported and the hips bent.
Education Statement: The IHDI recommends healthy hip
positioning for all babies to encourage normal hip development. Within
the womb, a baby spends a long time tucked in the fetal position, in
which both hips and knees are bent or flexed.
Baby in normal (fetal) womb
After birth, it takes several months for the joints to stretch out
naturally. Babies that have been in the breech (bottom first) position
may need even more time to stretch out naturally. The hip joint is a
ball and socket joint. During the first few months of life the ball is
more likely to be loose within the socket because babies are naturally
flexible and because the edges of the socket are made of soft cartilage
like the cartilage in the ear. If the hips are forced into a
stretched-out position too early, the ball is at risk of permanently
deforming the edges of the cup shaped socket (hip dysplasia) or
gradually slipping out of the socket altogether (hip dislocation). Hip
dysplasia or dislocation in babies is not painful so this may go
undetected until walking age and may also result in painful arthritis
during adulthood. The risk of hip
dysplasia or dislocation is greatest in the first few months of life.
By six months of age, most babies have nearly doubled in size, the hips
are more developed and the ligaments are stronger, so are less
susceptible to developing hip dysplasia.
The most unhealthy position for the hips during infancy is when the
legs are held in extension with the hips and knees straight and the legs
brought together, which is the opposite of the fetal position. The risk
to the hips is greater when this unhealthy position is maintained for a
long time. Healthy hip positioning avoids positions that may cause or
contribute to development of hip dysplasia or dislocation. The
healthiest position for the hips is for the hips to fall or spread
(naturally) apart to the side, with the thighs supported and the hips
and knees bent. This position has been called the jockey position,
straddle position, frog position, spread-squat position or human
position. Free movement of the hips without forcing them together
promotes natural hip development.
Some types of baby carriers and other equipment may interfere with
healthy hip positioning. Such devices include but are not limited to
baby carriers, slings, wraps, pouches, car seats, exercisers, rockers,
jumpers, swings, bouncers and walkers, and molded seating items. These
devices could inadvertently place hips in an unhealthy position,
especially when used for extended periods of time. Any device that
restrains a baby’s legs in an unhealthy position should be considered
a potential risk for abnormal hip development. It is also important to
assess the size of the baby and match the device and carrier to the size
of the child so that the hips can be in a healthy position during
transport. Parents are advised to research the general safety and risks
of any device they wish to use. When in doubt, we recommend involving
your primary health-care provider in any further decision-making that
may be medically relevant.
These series of drawings demonstrate typical devices that allow
healthier hip positioning in comparison to those which do not.