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Updated: Aug 23, 2026
Instrumentation of Near-term Fetal Sheep for Multivariate Chronic Non-anesthetized Recordings
Published on: October 25, 2015
The effects of low-dose endotoxin on the umbilicoplacental circulation in preterm sheep
A B C Coumans1, Y Garnier, S Supçun
1Department of Obstetrics and Gynecology, University of Maastricht, Maastricht, The Netherlands.
Objective:
In the present study we examined the effects of low-dose endotoxin (lipopolysaccharides, LPS) on continuously recorded umbilical blood flow.
Methods:
Twenty fetal sheep were catheterized at a gestational age of 107 +/- 1 days. A flow probe was placed around either the common umbilical artery or one single umbilical artery. Three days later fetuses received either 100 or 500 nanograms of LPS (n = 14) or 2 mL saline (n = 6) intravenously. Six fetuses died within 12 hours after LPS. Fetal heart rate (FHR), mean arterial pressure (MAP), and umbilical blood flow (Q(umb)) were monitored for 3 days.
Results:
FHR increased by 25 +/- 4% at 4-5 hours after LPS (P <.01) and was elevated for 15 hours after LPS. MAP increased by 18 +/- 5% 1 hour after LPS (P <.01) and returned to control value 4-5 hours after LPS. Q(umb) began to decrease 1 hour after LPS and was minimal (-30 +/- 7%, P <.001) at 4-5 hours after LPS. Q(umb) slowly returned to the control value at 12 hours after LPS. Placental vascular resistance increased by 73 +/- 37% (P <.01), whereas pH did not appreciably change.
Conclusion:
Intravenous application of endotoxin caused a substantial and long-lasting decrease in umbilical blood flow resulting in fetal hypoxemia without acidemia. These effects may be of significance in the development of fetal brain damage associated with intrauterine infection.