Amniotic fluid concentrations of secreted pregnancy-associated endometrial alpha 1- and alpha 2-globulins (alpha 1- and alpha 2-PEG).

The levels of pregnancy-associated endometrial alpha 1- and alpha 2-globulins (alpha 1- and alpha 2-PEG), the two major proteins synthesized and secreted by the endometrium in vitro, have been assayed in 210 amniotic fluid specimens obtained at termination of pregnancy or by amniocentesis, or at delivery. alpha 1-PEG was undetectable until week 10 and thereafter rose to peak levels between weeks 20 and 24. Levels fell 15-fold by week 35 but substantial amounts were still present at parturition. alpha 2-PEG was present at highest levels during early pregnancy, at weeks 6-15, but thereafter levels rapidly fell until during weeks 31-42 alpha 2-PEG was detectable in only 3 of 25 specimens. During weeks 15-20, when alpha 2-PEG levels fell and alpha 1-PEG levels rose, a high correlation was observed between the week of gestation and the log of the ratios of the concentration of these proteins. These observations provide the opportunity to assess the role of endometrial and decidual dysfunction in the aetiology of pregnancy disorders.