Magnesium sulfate treatment of preterm labor as a cause of abnormal neonatal bone mineralization.

Twelve infants born to mothers who received i.v. magnesium sulfate for > 6 weeks for the cessation of preterm labor were evaluated radiographically shortly after birth. All infants were born at > 33 weeks gestational age. All twelve infants demonstrated consistent and unique radiographic abnormalities in the metaphyses of their long bones. The extent of abnormality was at least partially related to the length of magnesium sulfate exposure, and appeared to completely resolve within the first few months of life.