The disappearance rate of pregnancy-associated plasma protein-A (PAPP-A) after the end of normal and abnormal pregnancies.

PAPP-A is a macromolecular glycoprotein associated with human pregnancy. In vitro, PAPP-A is produced by explant cultures of trophoblast and decidua. The present work was undertaken to see if the presence of decidua had any effect on the disappearance rate of PAPP-A after removal of the placenta either by surgery or by spontaneous delivery. PAPP-A was measured before and at different times after a normal delivery (n = 6), after a termination of early pregnancy (n = 11) and after surgery for ectopic pregnancy (n = 8). The half life of PAPP-A after normal delivery (52.9 +/- 25.8 h, SD) was significantly (p less than 0.03) less than after a first trimester termination (93.9 +/- 41.6 h). After surgery for ectopic pregnancy in patients with curetted decidua, PAPP-A disappeared significantly faster (p less than 0.005) then in patients with intact decidua (84.1 +/- 17.8 vs 241.2 +/- 81.5 h). These results indicate that PAPP-A continues to be produced by the decidua after removal of the trophoblast in early pregnancy.