The effects of isoproterenol on fetal oxygenation
Myers, R.E.; Joelsson, I.; Adamsons, K.
Acta Obstetricia et Gynecologica Scandinavica 57(4): 317-322
1978
ISSN/ISBN: 0001-6349 PMID: 29437 Document Number: 134189
Infusion of isoproterenol (1 .mu.g/kg per min, i.v.) into the anesthetized pregnant rhesus monkey near term consistently reduced fetal oxygenation, despite diminishing myometrial activity. The decline in pO2 [O2 partial pressure] of fetal arterial blood (mean = 4.3 .+-. 2.3 mmHg SD) was accompanied by an increase in pCO2 [CO2 partial pressure] tension (mean = 4.6 .+-. 2.7 mmHg) and a decline in pH (mean = 0.04 .+-. 0.02 SD). There was an increase in heart rate and a widening of pulse pressure in the mother and also in the adequately oxygenated fetus providing evidence that the agent crosses the placenta. The poorly oxygenated fetuses developed bradycardia and hypotension. Administration of isoproterenol directly to the fetus elicited similar changes in the composition of blood, blood pressure and heart rate to those observed after administration of the agent to the mother.