Does parity affect the neonatal outcome of very-low-birth-weight infants?

Objective: To evaluate the impact of parity on the neonatal outcome (survival, bronchopulmonary dysplasia and severe intraventricular hemorrhage) of very-low-birth-weight infants, accounting for sociodemographic, obstetric and perinatal variables. Study design: One hundred and eleven singleton premature infants with birth weights of 750-1250 grams, delivered between 1990 and 1994 and treated in the Hadassah University Hospitals in Jerusalem, were evaluated. In the analyses, variables with statistically significant association with the outcome variables were identified and entered together with parity as explanatory variables in a logistic regression. The results were analyzed with and without the inclusion of respiratory distress syndrome, representing an index of initial illness severity, in the multivariate model. Results: Neonatal mortality was higher in the 2-11 parity group when compared with first born infants. This association was of borderline statistical significance (OR=3.3; P=0.09), and was evident only upon exclusion of respiratory distress syndrome from the equation. There was no association between parity and the development of bronchopulmonary dysplasia. The risk for developing severe intraventricular hemorrhage was higher in offspirngs of multiparous women (OR=4.6; P=0,08 for parity 2-4, and OR=7.6; P=0.03 for parity 5-11). Respiratory distress syndrome was significantly associated with all the outcome variables and, to some extent, masked the relevance of pregnancy duration. A short hospitalization period before delivery was associated with increased mortality and with higher incidence of severe intraventricular hemorrhage. High initial Apgar scores appeared protective against severe intraventricular hemorrhage and bronchopulmonary dysplasia. Conclusion. Our results demonstrate a trend for increased survival of first born premature infants when compared with offsprings of subsequent deliveries, and an association between advanced parity and the development of severe intraventricular hemorrhage. Confirmation of these data by other studies is required before resultant implications are considered.