PRENATAL PREDICTION OF FETAL LUNG MATURITY BY MEASURING FETAL MAIN PULMONARY ARTERY DOPPLER INDICES

Background: Respiratory distress syndrome (RDS) is a leading cause of neonatal morbidity and mortality, particularly in preterm births. Non-invasive methods to predict fetal lung maturity are needed to guide obstetric decisions and reduce neonatal complications. Fetal main pulmonary artery (MPA) Doppler evaluation has been proposed as a promising tool. The present study aimed to evaluate the diagnostic performance of fetal MPA Doppler indices in predicting fetal lung maturity and neonatal RDS. Methods: This prospective observational study included 50 pregnant women between 28–40 weeks gestation at SAMC & PGI, Indore. All underwent real-time obstetric ultrasonography with MPA Doppler assessment (RI, PI, AT, ET, AT/ET ratio). Neonatal outcomes including birth weight, gestational age at birth, sex, NICU admission, and diagnosis of RDS were documented. Data were analyzed using SPSS v26.0, with calculation of sensitivity, specicity, PPV, and NPV for each Doppler parameter. Results: Of 50 neonates, 20 (40%) developed RDS. Mean birth weight (2055 ± 210 g vs 2265 ± 190 g, p = 0.002) and gestational age (33.1 ± 1.3 vs 34.3 ± 1.2 weeks, p = 0.002) were signicantly lower in the RDS group. RDS-positive neonates had higher PI (2.01 ± 0.22 vs 1.78 ± 0.18, p = 0.001) and RI (0.83 ± 0.05 vs 0.79 ± 0.04, p = 0.01), and reduced AT (37.4 ± 3.2 vs 41.2 ± 2.8 ms, p = 0.0005) and AT/ET ratio (0.20 ± 0.02 vs 0.23 ± 0.02, p < 0.001). AT/ET ≤0.21 predicted RDS with sensitivity 85%, specicity 80%, PPV 77%, and NPV 87%. All RDS neonates required NICU admission compared to 20% of non-RDS neonates (p < 0.001). Conclusion: Fetal MPA Doppler, particularly AT/ET ratio, provides a reliable non-invasive method for predicting neonatal RDS and may improve prenatal risk stratication.