Cardiovascular responses to maternal betamethasone administration in the intrauterine growth-restricted ovine fetus.
OBJECTIVE
The objective was to characterize the effect of glucocorticoid treatment on fetal organ blood flow and regional cerebral blood flow in normally grown fetuses and fetuses with intrauterine fetal growth restriction (IUGR).


METHODS
Studies were undertaken in both control and IUGR fetal sheep; growth restriction was induced by ligation of 1 umbilical artery. Fetuses received colored microspheres for organ blood flow calculations before and after 2 maternal betamethasone injections (BM1 and BM2).


RESULTS
Following BM1, cardiac output was significantly decreased in the control fetuses and blood flow to the heart and placenta was unchanged, whereas total cerebral blood flow was significantly decreased (P<.001), consistent with cerebral vasoconstriction. In the fetuses with IUGR, the cardiac output was significantly increased at +33 hours relative to BM1, and blood flow was increased in all organs; notably, there was a 2-fold increase in cerebral blood flow (P=.03).


CONCLUSIONS
The cardiovascular response of the fetus with IUGR to glucocorticoids is profoundly different from the control fetuses, which may induce both short- and long-term injury.
Miller
Suzanne L
SL
Department of Obstetrics and Gynecology, Monash Institute of Medical Research, Monash University, Clayton, VIC, Australia. suzie.miller@med.monash.edu.au
Supramaniam
Veena G
VG
Jenkin
Graham
G
Walker
David W
DW
Wallace
Euan M
EM
D000818:Animals; D001623:Betamethasone / Q000494:pharmacology* / Q000627:therapeutic use; D002319:Cardiovascular System / Q000187:drug effects*; D002560:Cerebrovascular Circulation; D003326:Coronary Circulation; D005260:Female; D005317:Fetal Growth Retardation / Q000188:drug therapy*; D005333:Fetus; D005938:Glucocorticoids / Q000494:pharmacology* / Q000627:therapeutic use; D010920:Placenta / Q000098:blood supply; D011247:Pregnancy; D012756:Sheep
D005938:Glucocorticoids; D001623:Betamethasone