Acceleration time-to-ejection time ratio in fetal pulmonary artery predicts the development of neonatal respiratory distress syndrome: A prospective cohort study

Sun Min Kim, Joong Shin Park, Errol R. Norwitz, Eun Ju Hwang, Hye Sim Kang, Chan Wook Park, Jong Kwan Jun

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15 Scopus citations


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.

Original languageEnglish
Pages (from-to)805-811
Number of pages7
JournalAmerican Journal of Perinatology
Issue number10
StatePublished - 7 Jan 2013


  • Doppler
  • fetal pulmonary artery
  • prematurity
  • preterm birth
  • respiratory distress syndrome

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