Abstract
Oxytocin was infused either continuously or in pulses to pregnant ewes to compare the responses of myometrial activity (contractures) and changes in fetal arterial Po2. Group 1 (n = 5) was infused with saline solution throughout the experiment. In group 2 (n = 5) oxytocin was infused continuously (160 μU · kg-1 · min-1) for 7 days whereas group 3 (n = 5) ewes received 960 μU · kg-1 · min-1 for 5 minutes every 30 minutes for 7 days. Contracture frequency increased in both oxytocin-infused groups. With continuous infusion contracture frequency returned to preinfusion levels during the last 4 days of infusion, whereas with pulsatile infusion contracture frequency remained increased throughout the infusion period. Fetal arterial Po2 was decreased throughout the 7 days of infusion in both oxytocin-infused groups. Pulsatile group fetal arterial Po2 levels remained decreased after the oxytocin infusion was stopped. These findings show; (1) Myometrial response to oxytocin in late pregnant ewes is influenced by the mode of administration; (2) administration of oxytocin to pregnant ewes resulted in a decrease in fetal Po2, and thus fetal hypoxemia cannot be attributed exclusively to increased contracture frequency.
Original language | English (US) |
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Pages (from-to) | 242-247 |
Number of pages | 6 |
Journal | American Journal of Obstetrics and Gynecology |
Volume | 160 |
Issue number | 1 |
DOIs | |
State | Published - Jan 1989 |
Externally published | Yes |
Keywords
- Oxytocin
- fetal oxygenation
- myometrial activity
ASJC Scopus subject areas
- Obstetrics and Gynecology