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[Concentration of estrogen and progesterone receptors in the lower uterine segment at term labor]
M Winkler1, S Zlantinsi, B Kemp
1Frauenklinik für Gynäkologie und Geburtshilfe, Universitätsklinikum der Rheinisch-Wesffälischen Technischen Hochschule Aachen. mwinkler@post.klinikum.rwth-aachen.de
Background:
To determine cytosol estrogen and progesterone receptor concentrations in the human lower uterine segment in different stages of cervical dilatation during parturition at term.
Patients And Methods:
Biopsy specimens of the lower uterine segment were obtained from 51 women undergoing non-elective cesarean section at term. The stage of cervical dilatation at the time of cesarean section was < 2 cm (N = 14), 2 to < 4 cm (N = 13), 4 to 6 cm (N = 11) or > 6 cm (N = 13). The cytosolic estrogen and progesterone receptor concentrations were determined by enzyme immunoassays.
Results:
Median estrogen receptor concentrations at < 2 cm and at 2-< 4 cm cervical dilatation were 2.12 fmol/mg protein and 2.03 fmol/mg protein, respectively. After a significant drop at 4-6 cm cervical dilatation (median: 1.08 fmol/mg protein), estrogen receptor concentrations raised again at > 6 cm cervical dilatation (median: 2.00 fmol/mg protein). Median progesterone receptor concentration was 84.7 fmol/mg protein at < 2 cm cervical dilatation, diminished significantly at 2-< 4 cm cervical dilatation (36.6 fmol/mg protein) and increased at further cervical dilatation (4-6 cm: 75.7 fmol/mg protein; > 6 cm: 83.7 fmol/mg protein).
Conclusions:
These data suggest that predominantly a decrease in cytosolic concentration of the progesterone receptor at the beginning of the active phase of first stage labor may play a crucial role in the hormonal control of cervical dilatation during parturition at term.