Osteopenia - premature infants Health Article

Alternative Names

Neonatal rickets; Brittle bones - premature infants; Weak bones - premature infants; Osteopenia of prematurity

Definition

Osteopenia is a decrease in the amount of calcium and phosphorus in the bone. This can cause bones to be weak and brittle, and increases the risk for broken bones.

Causes, incidence, and risk factors

During the last 3 months of pregnancy, large amounts of calcium and phosphorus are transferred from the mother to the baby so that the baby's bones will grow.

A premature infant may not receive the proper amount of calcium and phosphorus needed to form strong bones. While in the womb, fetal activity increases during the last 3 months of pregnancy. This activity is thought to be important for bone development. Most very premature infants have limited physical activity, which may also contribute to weak bones.

Very premature babies lose much more phosphorus in their urine than do babies that are born full term.

A lack of vitamin D may also lead to osteopenia in infants. Vitamin D helps with the body absorb calcium from the intestines and kidneys. If babies do not receive or make enough vitamin D, calcium and phosphorous will not be properly absorbed. A liver problem called cholestasis may also cause problems with vitamin D levels.

Diuretics or steroids can also cause low calcium levels.

Symptoms

Most premature infants born before 30 weeks have some degree of osteopenia, but will not have any physical symptoms.

Infants with severe osteopenia may have decreased movement or swelling of an arm or leg due to an unknown fracture.

Signs and tests

Osteopenia is more difficult to diagnose in premature infants than in adults. The most common tests used to diagnose and monitor osteopenia of prematurity include:

• Blood tests to check levels of calcium, phosphorus, and a protein called alkaline phosphatase
• Ultrasound
• X-rays

Treatment

Therapies that appear to improve bone strength in infants include:

• Calcium and phosphorus supplements, added to breast milk or IV fluids
• Special premature formulas (when breast milk is not available)
• Vitamin D supplementation for babies with liver problems