[Changes of dehydroepiandrosterone (DHA), 16 alpha OH-DHA and estriol levels in maternal peripheral blood during late pregnancy and labor--measured by gas chromatography-mass spectrometry with application of deuterated steroids as internal standards (author's transl)].

Serum levels of DHA, 16 alpha OH-DHA and estriol (E3) were determined in maternal peripheral vein by gas chromatography-mass spectrometry (GC-MS) with application of deuterated steroids as internal standards during late pregnancy and labor. Deuterium labeled 3,4,4-d3-DHA, 3,4,4-d3-16 alpha OH-DHA and 2,4-d2-E3 were newly synthesized and highly specific method for determination of serum DHA, 16 alpha OH-DHA and E3 was developed by GC-MS. The mean total steroid concentrations in the third trimester (III), in the stage when patients had irregular contraction (P) and during the first stage of labor (1st) were as follows; DHA, 612.9 +/- 265.3, 877.5 +/- 365.6 and 1522.5 +/- 580.6, 16 alpha OH-DHA, 30.2 +/- 20.2, 49.4 +/- 21.9 and 161.3 +/- 43.6, E3, 50.9 +/0 25.7, 70.4 +/- 19.8 and 108.6 +/- 44.5 ng/ml (mean +/- S.D.). The values of these three steroids increased significantly from the III to the 1st. Correlation between the levels of total DHA and total E2 measured in ten patients individually in the III was 0.8665 (p less than 0.001) which changed to -0.6650 (p less than 0.01) and -0.5362 (p less than 0.05) in the stage of P and 1st. ACTH was given to eight pregnant women in the third trimester, and response of these steroids to ACTH was studied. In addition to these steroids, cortisol (F) levels were also measured by RIA. Following the administration, F increased significantly whereas no changes of DHA, 16 alpha OH-DHA and E3 levels were noticed suggesting that these steroids may not be influenced by maternal adrenal secretion. From the results obtained above, it is suggested that the endocrinological environment in maternal blood as indicated by correlations between DHA and E3 levels, changes prior to the onset of labor.