Assessment of fetal lung maturity and prediction of neonatal respiratory distress syndrome by MV-Flow imaging.

Summary

In a prospective two-part study, MV-Flow visualized fetal peripheral lung microvasculature and produced highly reproducible VIMV metrics that increased with gestational age. Lower VIMV predicted neonatal RDS, with each 1% increase in VIMV associated with roughly a 70% reduction in NRDS risk and predictive performance of 82% sensitivity and 84% specificity.

Key Findings

• MV-Flow visualized fine peripheral fetal lung vessels undetectable by conventional Doppler.
• VIMV was highly reproducible (ICC >0.92) and increased with gestational age (r≈0.8, P<0.001).
• Lower VIMV was associated with NRDS; each 1% VIMV increase reduced NRDS risk by ~65–73% (adjusted OR≈0.3, P<0.005).
• Peripheral-lung VIMV predicted NRDS with 82% sensitivity and 84% specificity.

Clinical Implications

MV-Flow VIMV could inform timing of antenatal corticosteroids, delivery planning, and neonatal team preparedness, reducing invasive testing and enabling targeted perinatal care.

Limitations

• Part 2 sample size was modest (n=42) and likely single-center, requiring external validation.
• Technology- and vendor-specific parameters may affect generalizability and standardization.

Future Directions

Multicenter validation, device-agnostic standardization, prospective integration with antenatal steroid timing, and head-to-head comparisons with existing lung maturity tests.