Metabolic Bone Disease of Prematurity (MBDP)

What Is MBDP?

MBDP happens when a baby’s bones don’t fully develop before birth. It is fairly common in babies born too early (premature), affecting about 40–54% of preterm babies.

It was previously referred to as osteopenia of prematurity or rickets of prematurity, but MBDP is now the preferred name. It covers a wide range of bone concerns—from small changes found on lab tests to weak bones or even fractures (broken bones).

What Causes MBDP?

Most of a baby’s bone growth happens during the last three months of pregnancy. When a baby is born early, their bones don’t get all the nutrients and time they need to fully develop.

After birth, premature babies often need help with breathing and eating. Some of the treatments and medicines they need can also make it harder for bones to grow normally.

Babies may have a higher risk of MBDP if they:

• Are born very early (before 28 weeks)
• Have a very low birth weight (under 2–3 pounds)
• Need IV nutrition for 4 weeks or more
• Have digestive problems like necrotizing enterocolitis (NEC)
• Have chronic lung conditions (like bronchopulmonary dysplasia/BPD)
• Can’t move much or can’t bear weight for a while
• Need certain medicines such as steroids, diuretics, seizure medicines, or blood thinners

What Are the Signs & Symptoms of MBDP?

MBDP usually appears when a baby is 4–6 weeks old. Many babies don’t show any obvious symptoms at first, and changes are only found on blood tests.

In more serious cases, doctors may see:

• Rickets (soft or weak bones) on x-rays
• Pain or less movement in the arms or legs
• Bone fractures that show up on x-rays

How Is MBDP diagnosed?

Because MBDP can be “silent,” doctors often order regular blood tests starting around 4 weeks old. Depending on the results, they may recommend:

• More blood or urine tests
• Monitoring over time
• Starting treatment

How Is MBDP Treated?

Treatment depends on the baby’s needs. It may include:

• Supplements like calcium or phosphorus
• Extra vitamin D or special forms of vitamin D
• Orthopedic care if fractures are found

The goal is to help the bones get stronger and grow as they should.

What to Expect with Our Care Team

If MBDP is suspected or diagnosed, our team may see your baby while they’re still in the hospital. We work closely with the NICU team, dietitians, and pharmacists to make sure your baby is getting the right nutrition and support.

After your baby goes home, we’ll continue to follow their bone health and recommend any needed tests or treatments.

Looking Ahead 

Every NICU may handle MBDP a little differently. We are working with other hospitals to create the best possible care plans to support healthy bone growth in premature babies.