title: Human fetal foramen ovale flow velocity waveforms relative to fetal breathing movements in normal term pregnancies.
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.
authors.affiliation: Department of Obstetrics and Gynecology, Academic Hospital Rotterdam-Dijkzigt, The Netherlands.
authors.forename: J
authors.initials: J
authors.lastname: van Eyck
authors.forename: P A
authors.initials: PA
authors.lastname: Stewart
authors.forename: J W
authors.initials: JW
authors.lastname: Wladimiroff