[Concentrations of steroid hormones in maternal vein, amniotic fluid and chorionic tissue during early stages of pregnancy].

: To study the steroid concentration in human amniotic fluid in early stages of pregnancy between 6-10 weeks, progesterone (P4), 17 alpha-OH-progesterone (17P4), estrone (E1), estradiol (E2) and estriol (E3) levels in amniotic fluid (AF), maternal vein (MV) and chorionic tissue (CH) were measured by RIA. The levels of P4, 17P4, E1, E2 and E3 in CH were significantly higher than in AF and MV. The levels of P4 and E1 in AF were significantly higher than in MV, but the levels of 17P4 in MV were higher than in AF between 6-10 weeks of gestation. Although a peak at 7th week of gestation in AF was noticed, the levels of P4 increased gradually between 6-10 weeks of gestation in AF,MV and CH. There was no significant change in 17P4 levels in AF and CH, except for a slight decrease between 6-8 weeks of gestation in MV. The levels of E2 in MV increased after the 9th week of gestation and the levels were significantly higher than in AF. All estrogens (Es) in CH significantly increased at 10th week of gestation. The levels of P4 in AF and that in CH correlated well. A significant correlation was observed between the levels of E1 and E3 in MV and in CH. These results indicate the possible transference of P4 from CH to AF rather than that to MV. The transference of Es from CH to AF seems to be less than that of P4.(ABSTRACT TRUNCATED AT 250 WORDS)