Doppler Assessment of Fetal Pulmonary Artery as a Predictor in Neonatal Respiratory Distress

Abstract Background: Respiratory distress (RD) in newborns is a major cause of neonatal morbidity and mortality. Evaluating fetal lung maturity before labor is therefore essential, particularly in high-risk pregnancies where early termination may be considered. A key clinical challenge is identifying fetuses at risk for respiratory distress syndrome (RDS) to optimize the timing of delivery. Methods: This prospective study included pregnant women between 28 and 40 weeks of gestation. Doppler ultrasound was performed within 72 hours of delivery, assessing the fetal main pulmonary artery (MPA) parameters including resistance index (RI), pulsatility index (PI), and the acceleration-to-ejection time (At/Et) ratio. Scans were conducted using advanced ultrasound systems equipped with modern obstetric and fetal echocardiography software. After birth, neonates were evaluated for RD based on birth weight, APGAR score, clinical signs (such as tachypnea, chest retractions, grunting, and wheezing), and need for neonatal intensive care unit (NICU) admission. Results: The At/Et ratio of the fetal pulmonary artery showed significant predictive value for the occurrence of neonatal RDS. Among the Doppler indices assessed, the At/Et ratio demonstrated the highest sensitivity and specificity in predicting fetal lung maturity and the risk of neonatal respiratory distress. Conclusion: The At/Et ratio measured in the fetal pulmonary artery is a promising non-invasive marker for assessing fetal lung maturity and predicting the development of neonatal RDS. Larger studies are warranted to validate its clinical utility and potential as an alternative to amniocentesis in the prevention of neonatal RDS.