OBJECTIVE: This study investigates whether fetal pulmonary artery Doppler waveforms can predict the subsequent development of respiratory distress syndrome (RDS). STUDY DESIGN: A prospective cohort study was performed in women with impending preterm birth. Pulsatility index, resistance index, systolic-to-diastolic ratio, peak systolic velocity, and acceleration time-to-ejection time (At/Et) ratio were measured in the main pulmonary artery of fetus just before delivery. RESULTS: Neonates who developed RDS (n = 11) had significantly lower gestational age at birth than those without RDS (n = 31; median: 28.7 [range: 24.7 to 34.9] versus 32.9 [range: 25.7 to 36.0] weeks; p = 0.003); there was no difference in antenatal corticosteroid administration. Pulmonary artery At/Et ratio was significantly higher in fetuses that developed RDS compared with those that did not (median: 0.37 [range: 0.26 to 0.41] versus median: 0.30 [range: 0.21 to 0.44]; p = 0.008). RDS prediction score (=a hundredfold At/Et ratio) is significantly associated with the subsequent development of RDS after controlling for gestational age by logistic regression analysis (odds ratio = 1.31, 95% confidence interval 1.05 to 1.63, p = 0.017). CONCLUSION: An elevated At/Et ratio in the fetal pulmonary artery is independently associated with the development of RDS in preterm infants. These data suggest that fetal pulmonary artery Doppler velocimetry may provide a reliable noninvasive technique to evaluate fetal lung maturity, similar to the way in which middle cerebral artery Doppler has replaced amniocentesis for the assessment of fetal anemia. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.
OBJECTIVE: This study investigates whether fetal pulmonary artery Doppler waveforms can predict the subsequent development of respiratory distress syndrome (RDS). STUDY DESIGN: A prospective cohort study was performed in women with impending preterm birth. Pulsatility index, resistance index, systolic-to-diastolic ratio, peak systolic velocity, and acceleration time-to-ejection time (At/Et) ratio were measured in the main pulmonary artery of fetus just before delivery. RESULTS: Neonates who developed RDS (n = 11) had significantly lower gestational age at birth than those without RDS (n = 31; median: 28.7 [range: 24.7 to 34.9] versus 32.9 [range: 25.7 to 36.0] weeks; p = 0.003); there was no difference in antenatal corticosteroid administration. Pulmonary artery At/Et ratio was significantly higher in fetuses that developed RDS compared with those that did not (median: 0.37 [range: 0.26 to 0.41] versus median: 0.30 [range: 0.21 to 0.44]; p = 0.008). RDS prediction score (=a hundredfold At/Et ratio) is significantly associated with the subsequent development of RDS after controlling for gestational age by logistic regression analysis (odds ratio = 1.31, 95% confidence interval 1.05 to 1.63, p = 0.017). CONCLUSION: An elevated At/Et ratio in the fetal pulmonary artery is independently associated with the development of RDS in preterm infants. These data suggest that fetal pulmonary artery Doppler velocimetry may provide a reliable noninvasive technique to evaluate fetal lung maturity, similar to the way in which middle cerebral artery Doppler has replaced amniocentesis for the assessment of fetal anemia. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.