Prenatal ritodrine administration and the incidence of respiratory distress syndrome in premature infants.

Prenatal exposure to ritodrine may be associated with a lower incidence of RDS in premature infants, independent of its effect on prolongation of pregnancy. OBJECTIVE: The purpose of this study was to assess the neonatal respiratory outcome of premature infants according to whether their mothers were treated prenatally with ritodrine. STUDY DESIGN: A retrospective review was done of all 247 infants born at 34 weeks of gestation or less in our hospital during a 6-year period. A multivariate logistic regression was used to adjust for possible confounding variables. RESULTS: Among the ritodrine-exposed infants respiratory distress syndrome developed in 9.5% (4/42) compared with 28% (57/205) in the unexposed group (p < 0.012; adjusted odds ratio 4.88, 95% confidence interval 1.27 to 18.70). The gestational age and birth weight were similar in the two groups. The incidence of transient tachypnea of the newborn and other neonatal complications was not statistically different between the two groups. CONCLUSION: Ritodrine was associated with a significantly lower incidence of respiratory distress syndrome in premature infants, independent of the effect of ritodrine on prolongation of pregnancy.