The localization of pregnancy proteins (hPL, SP1 and PAPP-A) in intra- and extrauterine pregnancies.

The localization of human placental lactogen (hPL), pregnancy-specific beta-1 glycoprotein (Schwangerschaftsprotein 1, SP1) and pregnancy-associated protein A (PAPP-A) was examined in intrauterine and tubal ectopic gestation (n = 5) by the immunoperoxidase technique. The distribution of hPL and SP1 was identical in placental tissues obtained from intra- and extrauterine pregnancies, being uniformly seen throughout the syncytiotrophoblast. hPL and SP1 were not demonstrated in uterine decidual tissue from ectopic pregnancies. During early (week 8) intrauterine pregnancy, PAPP-A was not restricted to the mature syncytiotrophoblast, being observed also in some trophoblast-like cells adjacent to islands of syncytiotrophoblast. In contrast, in ectopic gestation, PAPP-A was observed in these cells at six weeks' gestation only. We were unable to detect PAPP-A in trophoblastic tissue of chorionic villi and uterine decidual tissue from ectopic gestation.