  Premature births can lead to complications, with fetal lung immaturity being
a primary concern. Currently, fetal lung maturity (FLM) requires an invasive
surfactant extraction procedure between the 32nd and 39th weeks of pregnancy.
Unfortunately, there is no non-invasive method for FLM assessment. This work
hypothesized that fetal breathing movement (FBM) and surfactant levels are
inversely coupled and that FBM can serve as a proxy for FLM estimation. To
investigate the correlation between FBM and FLM, antenatal corticosteroid (ACS)
was administered to increase fetal pulmonary surfactant levels in a high-risk
35th-week pregnant woman showing intrauterine growth restriction. Synchronous
sonographic and phonographic measurements were continuously recorded for 25
minutes before and after the ASC treatments. Before the ACS injection, 268
continuous movements FBM episodes were recorded. The number of continuous FBM
episodes significantly decreased to 3, 43, and 79 within 24, 48, and 72 hours,
respectively, of the first injection of ACS, suggesting an inversely coupled
connection between FBM and surfactant level s. Therefore, FBM may serve as a
proxy for FLM estimation. Quantitative confirmation of these findings would
suggest that FBM measurements could be used as a non-invasive and widely
accessible FLM-assessment tool for high-risk pregnancies and routine
examinations.
