Doppler velocimetry in the adrenal artery in human fetuses.
BACKGROUND
Fetal hypoxia and/or acidosis causes redistribution of blood flow to the high-priority organs including the adrenal glands. Although this phenomenon is well described in the human cerebral and placental circulations using Doppler velocimetry, there are few reports about the adrenal glands.


OBJECTIVE
To clarify the gestational age-related changes in adrenal blood flow in normal fetuses and fetuses at risk of hemodynamic derangement.


METHODS
In 153 normal cases, the resistance indices (RIs) calculated from the blood flow velocity waveforms (FVWs) in the middle adrenal artery (MAA) were obtained from 24 weeks to construct nomogram using regression analysis. Twenty-seven complicated cases were divided according to the 5%ile RI values in the MAA, and clinical outcomes were retrospectively compared.


RESULTS
The RI values in the MAA increased until 31 weeks and decreased thereafter. The 50%ile regression curve was represented as RI=-0.000914 (weeks)(2)+0.0579 weeks-0.181. Of the 27 complicated cases, 13 had RIs in the MAA below the 5%ile. Cases with low RI had significantly higher RI ratio in regard of UA/MCA; higher occurrence of abnormal FHR patterns on observation; higher incidence of cesarean delivery for nonreassuring fetal well-being status; earlier gestational age at delivery; lower birth weights and longer periods of admission to NICU than the cases with normal RI.


CONCLUSIONS
We have described the nomogram for the RI in the MAA. In conditions of fetal hypoxia or acidemia, blood flow redistribution to the adrenal glands may occur and the analysis of the adrenal artery FVWs may be useful in detection of fetal altered hemodynamics.
Fujita
Y
Y
Department of Obstetrics and Gynecology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
Satoh
S
S
Nakano
H
H
D000311:Adrenal Glands / Q000098:blood supply* / Q000000981:diagnostic imaging* / Q000196:embryology; D000328:Adult; D001158:Arteries / Q000000981:diagnostic imaging; D001783:Blood Flow Velocity; D005260:Female; D005865:Gestational Age; D006801:Humans; D011247:Pregnancy; D012016:Reference Values; D015203:Reproducibility of Results; D012212:Rheology; D018608:Ultrasonography, Doppler / Q000379:methods*; D016216:Ultrasonography, Prenatal / Q000379:methods*