Hypocalcemia refers to an abnormally low blood calcium level. Calcium levels can be measured at the bedside or in the lab.

A healthy baby's body usually has very careful control of blood calcium levels. There are several common causes of hypocalcemia in the sick newborn, including prematurity, stress, infection, maternal diabetes, and some medications. There are also some rare illnesses that can result in low calcium levels.

Calcium is a salt that is important to many systems in the body, especially heart and muscle function. There are frequently no signs in babies with hypocalcemia -- the diagnosis is usually made when a blood test that measures the calcium is low. Sometimes, babies with low calcium levels are jittery, and rarely even have seizures.

For the short-term, severe hypocalcemia may cause jitteriness or seizures. For the long-term, prolonged low calcium supply results in poor bone formation (osteopenia) which may result in very brittle bones that are prone to fractures.