A Novel Combination of Ultrasound Patterns of Fetal Breathing Movements for the Assessment of Fetal Lung Maturity

Abstract

Objective: Several patterns of fetal breathing movements (FBMs) i.e. abdominal wall movements,
thoracic movements (TMs), nasal fluid flow velocity waveforms (NFFVW) were investigated by
ultrasound (US) technology and related to fetal pulmonary maturity/immaturity, i.e., fetal lung maturity
(FLM) tests and neonatal outcome in order to validate our hypothesis that some FBMs patterns may
indicate that the fetal lung is mature or immature, regardless of gender, weight and gestational age.
Main outcome measures: We prospectively enrolled 39 high-risk pregnancies in
whom a complete US study of FBMs was performed and correlated to FLM tests. All women delivered
by cesarean section within 24 hours from amniocentesis, and neonatal outcome was evaluated up to 7
days after birth. US-FLM was defined as the presence of nasal fluid flow velocity waveforms (NFFVW)
detected by pulsed Doppler and spectral analysis, synchronous with thoracic movements (TMs)
detected by M-mode. An US guided amniocentesis was performed in order to collect amniotic fluid (AF)
and FLM was evaluated byL/S (lecithin/sphingomyelin) determination, phosphatidylglycerol (PG)
analysis and lamellar bodies count.
Results: Diagnostic accuracy for US evaluation of FLM, with NRDS as endpoint parameter, was as
follows: sensitivity: 100%, specificity: 80%, PPV: 73% and NPV: 100%.
Conclusion: FBMs are known to reflect pulmonary development and maturity and thus, are
conceivably correlated with the risk of the newborn infant to develope RDS after birth. Synchronous
presence of NFFVW and TMs correlate accurately with conventional FLM tests. We suggest that this
non-invasive procedure may be helpful to assess FLM, using a rapid and low cost technique; its use is
particurlarly important when certain situations arise, e.g., amniocentesis refusal, religious concerns,
oligo-anhydramnios, laboratory logistic equipment or heavily stained AF sample.