Doppler measurements on branches of the uterine artery in normal, hypertensive and growth-retarded pregnancies.
The quality and reliability of pulsed Doppler recordings from branches of the uterine artery were tested by studying 37 normotensive pregnancies and 14 complicated by pregnancy-induced hypertension (PIH) lasting for several minutes. The coefficients of variation of mean velocity and A/B ratio (= peak systolic/end diastolic velocity) were 0.06 and 0.08, respectively. Thus, calculations of A/B ratio from a limited number of heart beats should be reliable. Calculations were then made from uterine artery Doppler recordings in 65 normotensive pregnancies and 32 with PIH. A significantly higher A/B ratio was found in the PIH group. Among the normotensives, no statistically significant difference in A/B ratio was found between those who gave birth to appropriate-for-gestational-age (AGA) and small-for-gestational-age (SGA: less than 10th centile) infants. In the PIH group a significant difference was found; A/B: 1.95 versus 1.78 in the SGA and AGA groups, respectively. The latter was still significantly higher than the normotensive (= 1.60). Two PIH subgroups with equivalent blood pressures and proteinuria, but who gave birth to AGA or SGA infants, were compared. A/B ratio from the latter was significantly higher. These findings show that PIH is associated with increased uteroplacental vascular resistance; increased vascular pathology is associated with fetal growth retardation.
Janbu
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Department of Obstetrics and Gynaecology, Akershus Central Hospital, Nordbyhagen, Norway.
D000328:Adult; D001158:Arteries / Q000000981:diagnostic imaging; D001783:Blood Flow Velocity / Q000502:physiology; D005260:Female; D005317:Fetal Growth Retardation / Q000000981:diagnostic imaging* / Q000453:epidemiology; D006801:Humans; D006973:Hypertension / Q000000981:diagnostic imaging*; D011247:Pregnancy; D011249:Pregnancy Complications, Cardiovascular / Q000000981:diagnostic imaging*; D011256:Pregnancy Outcome / Q000453:epidemiology; D014465:Ultrasonics; D016216:Ultrasonography, Prenatal; D014599:Uterus / Q000098:blood supply*; D014655:Vascular Resistance / Q000502:physiology