Fetal peripheral bronchial fluid flow during breathing movement in normal pregnancies: a preliminary study

Objective To determine the fluid flow velocity waveforms in the fetal perip heral bronchus during fetal breathing movement by means of pulsed Doppler u ltrasonography. Design A preliminary cross-sectional study. Subjects Twenty-eight normal pregnant women between 32 and 38 weeks of gest ation. Methods Velocity waveforms from fetal peripheral respiratory fluid flow wer e acquired from the segmental bronchus (B-6 or B-8) which runs along the se gmental artery (A(6) or A(8)) The maximum velocity of the intrabronchial fl uid flow and duration of inspiratory and expiratory phases were quantified. Results The flow velocity signal from the fluid in the fetal segmental bron chus of 17 of the 28 fetuses was detected. We observed two types of fetal b reathing movement. Conclusion During fetal breathing movement, the fluid in the fetal respirat ory tract moves in the fetal segmental bronchus. This movement can be detec ted by pulsed Doppler velocimetry aided by power Doppler ultrasonography.