Correlations of maternal and fetal endocrine events with uterine pressure changes around parturition in the ewe

Abstract

In 4 ewes maternal peripheral plasma concentrations of progesterone were still elevated at the onset of parturient uterine activity. Fetal and maternal plasma concentrations of estrogen started to rise before parturition and concentrations in maternal plasma were positively correlated with parturient uterine activity (P < 0.05; r [correlation coefficient] = +0.42). Fetal plasma concentrations of corticosteroids were positively correlated with fetal plasma concentrations of estrogen (P < 0.01; r = +0.65), but negatively correlated with maternal peripheral plasma progesterone concentrations (P < 0.05; r = -0.50). Before parturition plasma concentrations of PG[prostaglandin]F rose but stayed high only in maternal peripheral plasma. Maternal peripheral plasma concentrations of PGF were positively correlated with uterine activity (P < 0.05; r = +0.79) and plasma concentrations of estrogen (P < 0.05; r = +0.79), but negatively correlated with plasma concentration of progesterone (P < 0.01; r = -0.54).