Objective:To determine if fetal heart rate (FHR) decelerations peridically occur with uterine contractures during 6 hours' induced hypoxemia in goats.
Methods:In five chronically catherized goat fetuses at 125-130 days' gestation, incidence of FHR decelerations was compared between 6 hours' control time and 6 hours' induced hypoxemia with two-way ANOVA and Duncan's multiple range test. Three other fetuses were used as controls for circadian rhythm.
Results:Fetal Pao2 was significantly decreased from 26.1 to 16.3 mmHg without acidemia. During hypoxemia, 42 decelerations were induced along with 5 initial decelerations during the acute phase hypoxemia. Incidence of decelerations increased significantly from 0.07 ± 0.15 per hour in 6-hour controls to 1.40 ± 0.28 per hour during 6 hours' induced hypoxemia. Short-term variability and long-tern variability of the 42 decelerations were significantly increased. These variabilities were also increased during the 5 initial decelerations. Grequency of uterine contractures did not change during hypoxemia. There was an observable association of FHR deceleratious with uterine contractures during hypoxemia.
Conclusion:Fetal heart rate decelerations occurred periodically in association with uterine contracture during induced 6 hours' hypoxemia, which were characterized by show onset and recovery with increases in variability.
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