title: Blood flow velocity waveforms from the fetal external iliac artery as a measure of lower extremity vascular resistance.
abstract: Blood flow velocities were recorded in the external iliac artery (EIA) and umbilical artery (UA) in 94 normal pregnancies and in 14 with intrauterine growth retardation (IUGR) between 25 and 36 weeks gestation. In normal pregnancy the pulsatility index (PI) in both vessels decreased significantly with advancing gestational age, reflecting a reduction in lower extremity and placental vascular resistance. The EIA PI/UA PI ratio also decreased significantly with gestational age suggesting that vascular resistance is more pronounced in the lower extremities. In the pregnancies with IUGR, PI values from both vessels were nearly always above the upper limit (+2 SD) of the normal curve reflecting increased vascular resistance at lower extremity and placental level. In two pregnancies, absent end-diastolic flow velocities in the umbilical artery were associated with reversed end-diastolic flow velocities in the external iliac artery.
authors.affiliation: Department of Obstetrics & Gynaecology, Erasmus University, Rotterdam, The Netherlands.
authors.forename: P A
authors.initials: PA
authors.lastname: Stewart
authors.forename: J W
authors.initials: JW
authors.lastname: Wladimiroff
authors.forename: T
authors.initials: T
authors.lastname: Stijnen
mesh_terms: D001783:Blood Flow Velocity; D005260:Female; D005312:Fetal Blood; D005317:Fetal Growth Retardation / Q000503:physiopathology*; D005865:Gestational Age; D006801:Humans; D007083:Iliac Artery / Q000503:physiopathology*; D011247:Pregnancy; D011673:Pulsatile Flow; D014469:Umbilical Arteries / Q000503:physiopathology; D014655:Vascular Resistance / Q000502:physiology