Understanding Your Baby's Hip Development

Learning that your newborn has a hip issue can feel overwhelming and frightening. It is natural to worry about how this might affect your child’s ability to walk or grow, but please know that you are not alone. Developmental Dysplasia of the Hip (DDH) is a common condition that specialists manage every day ^[1]. When caught early, most cases can be treated effectively, allowing children to develop normally ^[2].

What is DDH?

Developmental Dysplasia of the Hip is an umbrella term. This means it describes a range of different hip issues rather than a single problem ^[3]. Your doctor may use specific terms to describe your baby’s hips:

• Acetabular Dysplasia: The “socket” of the hip joint (the acetabulum) is too shallow to properly hold the “ball” (the femoral head) ^[3].
• Hip Instability: The joint is loose, and the ball may slide around more than it should during a physical exam.
• Subluxation: The ball is partially sliding out of the socket but is not completely disconnected.
• Dislocation: The ball has completely moved out of the socket ^[3].

The term “developmental” is used because the hip may be normal at birth but develop issues as the baby grows, or a mildly immature hip at birth may resolve on its own with time ^[4].

How a Healthy Hip Develops

To understand DDH, it helps to picture the hip as a ball-and-socket joint. For the socket to grow deep and strong, the ball must sit reliably within it ^[3].

The pressure of the ball sitting in the socket acts like a mold, encouraging the socket to curve around it. If the ball is loose or sits outside the socket, the socket may grow shallow or flat ^[3]. In DDH, the goal of treatment is to gently guide that ball back into the socket so they can grow together correctly.

How Common is DDH?

DDH is one of the most common orthopedic conditions in newborns, though the numbers vary depending on how it is defined. Roughly 1 to 2 babies out of every 1,000 are born with a dislocated hip ^[1]. However, when doctors include milder forms like instability or shallow sockets found on ultrasound, the rate can be as high as 5 to 30 per 1,000 babies ^[5].

While anyone can have DDH, certain factors increase the likelihood:

• Breech Positioning: Babies who spent time in a breech position (bottom or feet first) toward the end of pregnancy have a higher risk due to the cramped space in the womb ^[3][6].
• Family History: Having a close relative who had DDH increases the risk ^[6].
• Biological Sex: DDH is significantly more common in girls ^[6].

The Role of Swaddling

It is important to note that parents do not cause DDH; it is a developmental condition influenced by genetics, anatomy, and positioning before birth. However, how a baby is positioned after birth can affect an already susceptible hip.

For decades, researchers have observed that “tight swaddling”—where a baby’s legs are pulled straight down and wrapped tightly together—can restrict normal hip mechanics ^[7]. To support your baby’s hip development, use hip-safe swaddling:

• Allow Freedom of Movement: The blanket should be loose enough around the legs so the baby can bend their knees up and out ^[8].
• Avoid Leg Extension: Never pull the legs straight or wrap them tightly together ^[9].
• Safe Sleep Reminders: Always place your baby on their back on a firm, flat surface. Stop swaddling entirely as soon as your baby shows signs of trying to roll over.

Note that hip-safe swaddling is a healthy practice, but it does not treat an established case of DDH.

What to Expect Next

If your doctor suspects DDH, they will likely use a combination of physical exams and imaging. For babies under six months old, an ultrasound is the preferred tool because a newborn’s hip is made mostly of cartilage, which doesn’t show up well on an X-ray ^[10].

Because the infant hip is incredibly adaptable, stable and mildly immature hips are sometimes simply observed by the orthopedic team. For hips that require intervention, many respond well to a soft brace or harness that safely positions the legs, allowing the joint to deepen naturally as they grow ^[2]. The journey may involve extra appointments and equipment, but the goal is long-term, painless movement.