Duplex ultrasonography of the fetal aorta, umbilical artery, and placental arcuate artery throughout normal human pregnancy.
A cross-sectional duplex study of blood flow in the fetal aorta, umbilical artery, and arcuate arteries of 111 normal subjects was performed once at between 20 and 42 weeks gestation. Peak systolic velocity, end-diastolic velocity, mean velocity, and volume flow were measured in the fetal aorta, and systolic to diastolic (S/D) ratios were measured in all three vessels. Velocities show an inverse exponential (Y = Exp [1/X x B + C]) increase with gestational age, reaching a plateau just before term, while S/D ratios in the aorta and umbilical arteries show a linear decrease. Such findings are at variance with some published data. Our results suggest a reduction in fetal placental resistance at term and provide useful data concerning normal fetal and placental circulations.
Cameron
A
A
Department of Obstetrics and Gynecology, University of Calgary, Alberta.
Nicholson
S
S
Nimrod
C
C
Harder
J
J
Davies
D
D
Dempster
C
C
Garvey
P
P
D001011:Aorta / Q000196:embryology / Q000502:physiology*; D001158:Arteries / Q000502:physiology; D001783:Blood Flow Velocity; D003430:Cross-Sectional Studies; D005260:Female; D005333:Fetus / Q000502:physiology*; D005865:Gestational Age; D006801:Humans; D009200:Myocardial Contraction; D010920:Placenta / Q000098:blood supply*; D011247:Pregnancy; D011296:Prenatal Diagnosis; D012039:Regional Blood Flow; D014463:Ultrasonography / Q000379:methods*; D014469:Umbilical Arteries / Q000502:physiology*