Background: Newborn respiratory complication is one of the most prevalent and life-threatening disorders. The clinical indications of early newborn respiratory distress with consistent radiologic features. The Doppler examination of the primary pulmonary artery in the foetus has been proven to be beneficial. The foetal pulmonary artery At/Et ratio is linked to foetal gestational age and amniotic fluid foetal lung maturity (FLM) tests. The aim of the study was to assess the accuracy of foetal main pulmonary artery (MPA) Doppler indices in prediction of the development of neonatal respiratory distress syndrome (RDS) in diabetic mothers.Methods: This was a prospective observational study carried out on 100 cases of diabetic mothers in obstetrics and gynecology department, Tanta University during one year from the approval of the university counsel. The physician evaluated the foetal heart in a methodical manner after a regular ultrasound assessment that included foetal biometry, anomaly scan, measured foetal weight, and amniotic fluid index. Classic chest radiological features include reticulogranular patterns, air bronchogram and ground glass look, as well as the need for surfactant.Results: PI and RI were significantly higher in newborns with RDS than those without RDS (p=0.025 and 0.036 respectively) PSV and At/Et ratio were significantly reduced in neonates with RDS compared with RDS free ones (p=0.004 and <0.001 respectively). RI was significantly higher in neonates with RDS than those without RDS (P = 0.048) PSV and At/Et ratio were significantly reduced in newborns with RDS compared to RDS free ones (p=0.008 and <0.001 respectively). The ROC curve displayed that the cut off value of ≤0.25 for At/Et ratio was associated with a sensitivity of 76.92%, a specificity of 100.0%, a PPV of 100.0% and a NPV of 96.7% for prediction of neonatal RDS with AUC of 0.925 and p≤0.001.Conclusions: development of neonatal RDS in foetus of diabetic mothers with a cut off value of ≤0.25, a sensitivity of 76.92%, a specificity of 100.0%, a PPV of 100.0%, a NPV of 96.7% and AUC of 0.925 The usage of corticosteroids improved the Doppler indices of main pulmonary artery and is accompanied by less morbimortality related to RDS.