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Updated: Aug 17, 2026

Fetal Mouse Cardiovascular Imaging Using a High-frequency Ultrasound (30/45MHZ) System
Published on: May 5, 2018
The effects of isoproterenol on fetal oxygenation
Infusion of isoproterenol (1 microgram/kg/min, i.v.) into the anesthetized pregnant rhesus monkey near term consistently reduced fetal oxygenation, despite diminishing myometrial activity. The decline in pO2 of fetal arterial blood (mean = 4.3 +/- 2.3 mmHg S.D.) was accompanied by an increase in pCO2 tension (mean = 4.6 +/- 2.7 mmHg) and a decline in pH (mean = 0.04 +/- 0.02 S.D.). 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, and in blood pressure and heart rate, to those observed after administration of the agent to the mother.
Infusion of isoproterenol (1 microgram/kg/min, i.v.) into the anesthetized pregnant rhesus monkey near term consistently reduced fetal oxygenation, despite diminishing myometrial activity. The decline in pO2 of fetal arterial blood (mean = 4.3 +/- 2.3 mmHg S.D.) was accompanied by an increase in pCO2 tension (mean = 4.6 +/- 2.7 mmHg) and a decline in pH (mean = 0.04 +/- 0.02 S.D.). 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, and in blood pressure and heart rate, to those observed after administration of the agent to the mother.
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