title: Maternal plasma progesterone levels fall after rectal administration of estriol.
abstract: Maternal plasma unconjugated estriol (E3), progesterone (P), and estradiol (E2) levels were measured at 30-min intervals for 6 h after the rectal administration of a 100-mg E3 or placebo suppository to 28 pregnant women at term. Mean plasma unconjugated E3 levels showed a sustained rise approximately 50% above baseline levels 2 h after rectal E3 administration (P < 0.003). There was a simultaneous sustained fall of approximately 20% in mean plasma P levels (P < 0.05); the fall in mean P levels was greatest in the women who delivered within 48 h of E3 suppository administration (P < 0.05). There was no change in mean plasma E2 levels. This study demonstrates that a significant rapid increase in maternal circulating E3 levels can be obtained by the rectal administration of E3, and that this increase in maternal E3 levels is associated with a decrease in circulating P levels.
authors.affiliation: Department of Obstetrics and Gynaecology, University College and Middlesex School of Medicine, London, United Kingdom.
authors.forename: D J
authors.initials: DJ
authors.lastname: Moran
authors.forename: H H
authors.initials: HH
authors.lastname: McGarrigle
authors.forename: G C
authors.initials: GC
authors.lastname: Lachelin
mesh_terms: D000328:Adult; D004958:Estradiol / Q000097:blood; D004964:Estriol / Q000008:administration & dosage* / Q000097:blood / Q000494:pharmacology; D005260:Female; D006801:Humans; D007743:Labor, Obstetric; D010919:Placebos; D011247:Pregnancy / Q000097:blood*; D011374:Progesterone / Q000097:blood*; D013488:Suppositories; D013997:Time Factors
chemical_list: D010919:Placebos; D013488:Suppositories; D011374:Progesterone; D004958:Estradiol; D004964:Estriol