Rescue Antenatal Steroids and Pulmonary Function Tests in Preterm Infants

Rescue Antenatal Steroids and Lung Volumes in Preterm Infants

One course of steroids given to a mother before a premature delivery helps the lungs of the premature infant and decreases breathing problems. One course of antenatal steroids is the standard of care for threatened premature deliveries. It is unclear as to how long the benefit of one course of steroids last. The most benefit to the baby's lungs seem to occur if the steroids are given at least 24 hours before but within 7 days of a premature delivery. It is difficult to predict the timing of a preterm delivery so deliveries often do not occur within this time period. We hypothesize that the benefits of the steroids to the lungs wear off if the steroids are given more than 14 days before a preterm delivery, and that in these circumstances an extra course of steroids will help the premature baby's lungs and the premature baby will have less breathing problems as shown by lung function testing.

The primary purpose of this randomized, blinded placebo controlled trial is to quantify and compare measurements of pulmonary function (including respiratory compliance and lung volumes/functional residual capacity) of hospitalized preterm infants whose mothers received an initial course of antenatal corticosteroids, remained undelivered after 14 days and at < 34 weeks of gestation, and were then randomized to either a rescue course of antenatal corticosteroids or to a rescue course of placebo. In addition, follow-up pulmonary function tests, clinical outcomes, growth parameters, and the neurodevelopmental outcome of these infants will be followed.

Inclusion Criteria:

• Greater than 14 days after first course of antenatal steroids;
• Less than 34 weeks of gestation;
• Identified by primary physician as continued risk for preterm delivery;
• Informed consent

Exclusion Criteria:

• Major congenital anomalies
• Multiple gestation of triplets or greater
• Mother with insulin dependent diabetes