Although neonatal pulmonary hemorrhage is rare, it is associated with high mortality. We aimed to evaluate the risk factors associated with pulmonary hemorrhage in preterm infants and to describe the clinical course, including neonatal morbidity, of infants who developed pulmonary hemorrhage.

We performed a retrospective case-control study of 117 newborn infants aged less than 37 gestational weeks admitted to the neonatal intensive care unit of Daegu Fatima Hospital between January 1995 and December 2008. Control group infants without pulmonary hemorrhage were matched according to the gestational age, duration of mechanical ventilation, and birth weight range (≤100 g). Pulmonary hemorrhage was defined as the presence of hemorrhagic fluid in the trachea and severe respiratory decompensation.

Pulmonary hemorrhage occurred in 17 cases of very low birth weight infants (VLBW; birth weight < 1,500 g; median age, 3 days) and 22 cases of low birth weight infants (LBW; 1,500 g ≤ birth weight < 2,500 g; median age, 1 day). Antenatal maternal glucocorticoid treatment significantly reduced the incidence of pulmonary hemorrhage in VLBW infants. Low APGAR score (≤3 at 1 min) and acidosis at birth were associated with significantly high incidence of pulmonary hemorrhage in LBW infants.

Antecedent factors and timing of pulmonary hemorrhage of LBW infants were different from those of VLBW infants. The mortality rates of VLBW and LBW infants were 88.2% and 45.5%, respectively. Pulmonary hemorrhage was the principal cause of death in 66.6% VLBW infants and 40.0% LBW infants.