Changes in steroid hormones in plasma and myometrium and uterine activity in ewes during late pregnancy and parturition
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Updated: Aug 19, 2026

Instrumentation of Near-term Fetal Sheep for Multivariate Chronic Non-anesthetized Recordings
Published on: October 25, 2015
Abstract:
In 7 ewes during late pregnancy, peripheral plasma concentrations of oestrogens were correlated with uterine activity (P less than 0-01; r=+0-47). In myometrial tissue, the concentration of progesterone was similar to that in plasma; it rose to a plateau from Days 115 to 130 of pregnancy and then fell, but was still detectable during parturition. Myometrial oestrogen concentration was much higher than in plasma; from a peak at Days 100-115 it decreased, but rose sharply just before parturition.
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