Do survival and morbidity of very-low-birth-weight infants vary according to the primary pregnancy complication that results in preterm delivery?

OBJECTIVE: This retrospective study was conducted to determine whether predischarge survival and morbidity of very-low-birth weight infants varied according to the principal pregnancy complication that led to preterm delivery.

STUDY DESIGN: The hospital records of 535 consecutive live-born singleton infants who weighed between 500 and 1499 gm were reviewed, and five primary complications that resulted in preterm delivery were identified: (1) premature rupture of membranes (n = 244, 46%), (2) idiopathic preterm labor (n = 97, 18%), (3) antepartum hemorrhage (n = 58, 11%), (4) pregnancy-induced hypertension (n = 98, 18%), and (5) "other" complications (n = 38, 7%). Neonatal records were studied to identify the presence of respiratory distress syndrome, bronchopulmonary dysplasia, pulmonary interstitial emphysema, patent ductus arteriosus, necrotizing enterocolitis, intraventricular hemorrhage, retinopathy of prematurity, and infant death before hospital discharge. Logistic regression analysis was used to analyze the association of each pregnancy complication with the various forms of neonatal morbidity.

RESULTS: There were no statistically significant differences in discharge survival rates (range 71% to 88%) among infants born to women who experienced one of the five types of primary complications. Independent of all confounders, premature rupture of membranes was associated with a decreased risk of respiratory distress syndrome, bronchopulmonary dysplasia, pulmonary interstitial emphysema, patent ductus arteriosus, and intraventricular hemorrhage. Preterm labor was associated with an increased risk of pulmonary interstitial emphysema, patent ductus arteriosus, and intraventricular hemorrhage. Pregnancy-induced hypertension was associated with an increased risk of respiratory distress syndrome, pulmonary interstitial emphysema, and patent ductus arteriosus. Antepartum hemorrhage was associated with an increased risk of patent ductus arteriosus.

CONCLUSION: The principal pregnancy complication that led to preterm delivery significantly influenced predischarge morbidity but not the predischarge survival of live-born infants.