Reduced incidence of hyaline membrane disease in extremely premature infants following delay of delivery in mother with preterm labor: use of ritodrine and betamethasone.

Data from two groups of infants (24 to 28 weeks' gestational age) excluded from a controlled trial of the use of calf lung surfactant extract for the prevention of hyaline membrane disease are reported. The two groups were excluded from the trial because the mothers had received betamethasone for greater than 24 hours prior to delivery or because, on admission to the hospital, labor was too far advanced for proper informed consent to enter the trial. Attempts were made to delay delivery of threatened premature labor by the use of ritodrine in all mothers without evidence of infection, heavy vaginal bleeding, or severe preeclampsia and to induce surfactant production by maternal injection of betamethasone. A prospective scoring system and respiratory support variables were used to compare the groups. Infants born to mothers who successfully completed this regimen had a 28% incidence of hyaline membrane disease v a 68% incidence in infants in whose mothers it was unsuccessful due to inability to stop advanced labor (P = .001). Inspired oxygen, mean airway pressure, and ventilator rate were lower and the ventilator efficiency index was higher in the treated group during the first 48 hours of life. An aggressive approach to postpone premature delivery and to induce surfactant production by using tocolysis and a regimen of glucocorticoids reduces the incidence of hyaline membrane disease in very premature infants, 24 to 28 weeks' gestation.