Plasma progestagens and oestrogens in fetus and mother in late pregnancy.

R. J. Barnes, P. W. Nathanielsz, P. D. Rossdale, R. S. Comline, M. Silver

Research output: Contribution to journalArticlepeer-review

37 Scopus citations


Normal Thoroughbred and catheterized Pony mares and their fetuses were used. Fetal oestrogen and progestagen concentrations in late gestation were much higher than maternal values. A major feature of the umbilical steroid concentrations was a large venous-arterial difference in progestagens and total oestrogens throughout late gestation which may indicate a metabolic cycle in the fetus between progesterone and other steroid metabolites. Metabolites of 20alpha-dihydroprogesterone were present in high concentrations in maternal and fetal plasma. In Thoroughbreds, and to a lesser extent in Pony mares, plasma progestagens rose towards parturition while total plasma oestrogen fell. The only oestrogen which showed a rise in concentration near term was oestradiol-17beta. In one Pony mare and fetus, fetal plasma progestagen fell 24 to 36 hr before parturition when maternal peripheral progestagen concentrations remained high.

Original languageEnglish (US)
Pages (from-to)617-623
Number of pages7
JournalJournal of reproduction and fertility. Supplement
Issue number23
StatePublished - Oct 1 1975
Externally publishedYes

ASJC Scopus subject areas

  • Medicine(all)


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