Effect of antenatal administration of thyrotrophin releasing hormone on fetal flow velocity waveforms.
OBJECTIVE
To determine whether antenatal administration of thyrotrophin releasing hormone (TRH), to promote lung maturation, alters blood flow through the fetal middle cerebral, umbilical artery, or ductus arteriosus and through the maternal uterine arteries.


METHODS
The effect of transplacentally administered TRH on the fetal circulation was prospectively evaluated in 30 patients between 24 and 34 weeks' gestation. TRH (400 micrograms) was given to the mother intravenously either as a bolus or an infusion. Fetal effects were determined by measuring the maximum velocity and pulsatility index (PI) in middle cerebral artery, ductus arteriosus, uterine artery and umbilical artery Doppler waveforms. Measurements were made immediately before, and 10 and 60 minutes after maternal TRH administration.


RESULTS
Intravenous injection of TRH had no significant effect on PI in the uterine, umbilical, or middle cerebral artery and the ductus arteriosus within 60 minutes of administration in either group.


CONCLUSIONS
The antenatal use of TRH in conjunction with steroids for fetal lung maturity does not affect utero-placental or fetal haemodynamic variables, as measured by Doppler. These findings, therefore, do not support the suggestion that antenatal intravenous administration of TRH either as bolus or infusion may have immediate adverse vascular effects in the fetus.
Bajoria
R
R
Institute of Obstetrics and Gynaecology, Royal Postgraduate Medical School, Queen Charlotte's and Chelsea Hospital, London. r.bajoria@rpms.ac.uk
Stagiannis
K D
KD
Fisk
N M
NM
D000293:Adolescent; D000328:Adult; D000704:Analysis of Variance; D002536:Cerebral Arteries / Q000187:drug effects / Q000196:embryology* / Q000502:physiology; D004373:Ductus Arteriosus / Q000187:drug effects* / Q000502:physiology; D005260:Female; D006801:Humans; D007262:Infusions, Intravenous; D007275:Injections, Intravenous; D008168:Lung / Q000187:drug effects / Q000196:embryology; D008431:Maternal-Fetal Exchange; D011247:Pregnancy; D011262:Pregnancy Trimester, Second; D011446:Prospective Studies; D011673:Pulsatile Flow / Q000187:drug effects; D012039:Regional Blood Flow / Q000187:drug effects; D012044:Regression Analysis; D013973:Thyrotropin-Releasing Hormone / Q000008:administration & dosage*; D018617:Ultrasonography, Doppler, Pulsed; D016216:Ultrasonography, Prenatal; D014469:Umbilical Arteries / Q000187:drug effects* / Q000502:physiology; D014599:Uterus / Q000098:blood supply*
D013973:Thyrotropin-Releasing Hormone