To evaluate changes in feto-placental markers with plasma exchange in
pregnancy, two patients at varying stages of pregnancy referred to a t
ertiary care hospital and requiring plasma exchange for intercurrent p
roblems were evaluated. Alpha-fetoprotein, human chorionic gonadotropi
n, and free estriol were sequentially measured in the patients' plasma
and in the fluid removed, thus permitting calculations of permeabilit
y rates and clearances. Despite markedly different molecular weights,
all three feto-placental markers had similar permeabilities and cleara
nces. While in both patients maternal levels of alpha-fetoprotein and
human chorionic gonadotropin decreased rapidly with plasma separation
and rebounded rapidly to baseline, free estriol responded differently
and did not appear to decrease with therapy. Maternal levels of feto-p
lacental markers only transiently changed with plasma exchange during
pregnancy and rapidly returned to baseline with no apparent consequenc
es to the pregnancy. (C) 1994 Wiley-Liss, Inc.