Ex vivo human placental transfer and the vasoactive properties of hydralazine.
OBJECTIVE
The purpose of this study was to determine the placental transfer and fetal vascular effects of hydralazine in an ex vivo human placental system.


METHODS
Nine placentas from uncomplicated term vaginal or cesarean deliveries were studied by means of the ex vivo single-cotyledon perfusion system. Antipyrine was used for the reference compound in the determination of the clearance index of hydralazine. Fetal vascular effects of hydralazine were determined by the effects on the perfusion pressure of the fetal artery in a constant-flow open system. Variations in fetal pressure were analyzed with the 1-sample Student t test.


RESULTS
The clearance index of hydralazine ranged from 0.61 +/- 0. 18 to 0.73 +/- 0.14. The accumulation of hydralazine in the recirculated fetal compartment was linear in relationship to the maternal concentration. Fetal pressure changes were noted in 6 of the 9 placentas, or 66.6%. The mean change in pressure was -4.1 +/- 4.4 mm Hg (P =.0231).


CONCLUSIONS
Hydralazine readily crosses the ex vivo human placental perfusion system.
Magee
K P
KP
Department of Obstetrics and Gynecology, University of Texas Southwestern Medical Center, Dallas 75265-9032, USA.
Bawdon
R E
RE
D002851:Chromatography, High Pressure Liquid; D005260:Female; D005312:Fetal Blood / Q000378:metabolism; D006801:Humans; D006830:Hydralazine / Q000378:metabolism* / Q000494:pharmacology*; D066298:In Vitro Techniques; D008431:Maternal-Fetal Exchange; D010920:Placenta / Q000378:metabolism*; D011247:Pregnancy; D011312:Pressure; D014665:Vasodilator Agents / Q000378:metabolism* / Q000494:pharmacology*
D014665:Vasodilator Agents; D006830:Hydralazine