Abstract
Introduction: To determine the optimal time to deliver a baby prematurely due to various clinical situations safely, it is crucial to accurately assess fetal lung maturity. Sonography, a non-invasive technique for evaluating fetal lung maturity, can be useful in predicting the risk of developing neonatal respiratory distress compared to amniocentesis, which is an invasive procedure with associated risks.
Aim: This study aimed to determine if fetal main pulmonary artery doppler can predict the risk of developing respiratory distress syndrome in neonates.
Material and Methods: The participants in this prospective cross-sectional study were 75 pregnant women with gestational ages ranging from 34weeks to 36 weeks +6 days. Ultrasound doppler examination was conducted, and peak systolic velocity (PSV), Systolic /Diastolic ratio, pulsatility index, and resistive index were measured. The acceleration time/ejection time ratio was calculated for the fetal main pulmonary artery. The diagnostic accuracy of these values was tested for predicting neonatal respiratory distress.
Results: Of the 75 fetuses included in the study, 15 (20%) showed some signs of neonatal respiratory distress syndrome (RDS). The Acceleration time/Ejection time (AT/ET) ratio in the fetal pulmonary artery correlated significantly with the development of respiratory distress syndrome in neonates (P=0.001). Fetuses with respiratory distress syndrome had higher Pulsatility Index and Resistive Index values, while their AT/ET ratio was low. AT/ET was found to predict respiratory distress development with a cutoff value of 0.30 (sensitivity: 98.3 percent; specificity: 86.67 percent). Pulsatility Index and Resistive Index displayed lower sensitivity and specificity than AT/ET ratio.
Conclusion: The fetal main pulmonary artery AT/ET ratio has high sensitivity and specificity for predicting the development of neonatal respiratory distress syndrome. Thus, we recommend that a fetus with an AT/ET ratio of <0.30 be delivered to a facility with good neonatal care.

Key words: Newborn RDS, Fetal ultrasonography, Pulmonary artery, Antenatal