Role of fetal pulmonary artery Doppler parameters for predicting neonatal respiratory distress syndrome: A systematic review and meta-analysis of diagnostic accuracy.

Objective: To evaluate the diagnostic accuracy of fetal pulmonary artery Doppler parameters for predicting neonatal respiratory distress syndrome (NRDS). Data sources: MEDLINE, Scopus, Embase, and Google Scholar were searched through March 30, 2026. Study eligibility criteria: Studies reporting a fetal pulmonary artery Doppler parameter and diagnostic accuracy or continuous data for predicting NRDS were eligible. Methods: This systematic review followed PRISMA-DTA guidelines, and risk of bias was assessed with QUADAS-2. Pooled sensitivity, specificity, and likelihood ratios were estimated using a bivariate random-effects model. Hierarchical summary receiver operating characteristic curves estimate the area under the curve (AUC). Subgroup, sensitivity, and meta-regression analyses explored heterogeneity. Results: Twenty-eight studies (n = 3576) were included. Acceleration time-to-ejection time ratio (AT/ET; 21 studies) demonstrated the most robust performance (sensitivity 90%, specificity 87%, AUC 0.94). Peak systolic velocity (PSV) showed a numerically high but highly imprecise performance (sensitivity 85%, specificity 93%, AUC 0.94), followed by pulsatility index (PI; AUC 0.89) and resistance index (RI; AUC 0.86). PI and RI were significantly higher, and AT/ET, PSV, and mean velocity significantly lower, in fetuses whose neonates developed NRDS. Evidence for systolic-to-diastolic ratio, end-diastolic velocity, and mean velocity remained insufficient for pooled diagnostic accuracy analysis. Substantial heterogeneity was observed in the pooled diagnostic accuracy analyses. Conclusions: Fetal pulmonary artery Doppler ultrasonography, particularly AT/ET, PI, and RI, shows promising diagnostic performance for predicting NRDS, with AT/ET most consistent across gestational age strata. Although PSV yielded a numerically high AUC, its limited study number and imprecision preclude firm conclusions regarding diagnostic value.