Fetal and umbilical flow velocity waveforms between 10-16 weeks' gestation: a preliminary study.
Maximal flow velocity waveform recording was attempted in the umbilical artery, fetal descending aorta, and at the fetal intracerebral level using a cross-sectional study design in 77 normal singleton pregnancies between 10-16 weeks' gestation. At 10-12 weeks, end-diastolic flow velocities were always absent in the fetal descending aorta and umbilical artery, but were present in 58% of the intracerebral artery waveforms. The pulsatility index at all three levels decreased significantly with advancing gestational age, suggesting a reduction in fetal and umbilical placental vascular resistance during the late first and early second trimesters of normal pregnancy. Waveform changes were not related to fetal heart rate.
Wladimiroff
J W
JW
Department of Obstetrics and Gynecology, Academic Hospital Rotterdam-Dijkzigt, The Netherlands.
Huisman
T W
TW
Stewart
P A
PA
D000328:Adult; D001013:Aorta, Thoracic / Q000000981:diagnostic imaging / Q000502:physiology*; D001783:Blood Flow Velocity; D002536:Cerebral Arteries / Q000000981:diagnostic imaging / Q000502:physiology*; D005260:Female; D005333:Fetus; D005865:Gestational Age; D006340:Heart Rate, Fetal / Q000502:physiology*; D006801:Humans; D011247:Pregnancy; D012039:Regional Blood Flow; D016216:Ultrasonography, Prenatal; D014469:Umbilical Arteries / Q000000981:diagnostic imaging / Q000502:physiology*