The gonadotropic hormones and their subunits in human maternal and fetal circulation at delivery.

The blood levels of HCG, LH, their alpha and beta subunits, and FSH were measured by double-antibody radioimmunoassays in 20 normal pregnanat women and in matched fetal cord arterial and venous samples at term. High levels of HCG, alpha subunit, and HCGbeta subunit, with low levels of LHbeta and FSH, were detected in maternal sera. In the fetal circulation the major detectable components were alpha subunits and presumably HCG. There was no significant arteriovenous difference in any of the hormones in the fetal circulation and no correlation between levels of hormones in maternal and fetal circulation. Column chromatography of sera confirmed that alpha subunits were present independent of intact hormones in both maternal and fetal sera.