Human fetal foramen ovale flow velocity waveforms relative to fetal breathing movements in normal term pregnancies.

van Eyck, J; Stewart, P A; Wladimiroff, J W · Ultrasound Obstet Gynecol · 1991

case_series · Level IV

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Abstract

The relationship between foramen ovale flow velocity waveforms and high-amplitude fetal breathing movements was studied in ten normal term pregnancies using Doppler ultrasonography. Peak systolic and averaged flow velocities demonstrated a statistically significant increase during fetal breathing activity, suggesting a raised pressure gradient between the right and left atria. This could be explained by a temporal reduction in pulmonary venous return to the left atrium during the inspiratory phase of the fetal breathing cycle. The breathing-related increase in foramen ovale flow velocity suggests that fetal breathing activity facilitates the distribution of well-oxygenated blood to the aorta and cerebral circulation.