At this point a bit of terminology discussion is in order. The term
‘‘anapylactoid syndrome of pregnancy’’ was proposed as an alternative
name to AFE.39,40 Although the name never really caught on, an
occasional author still makes reference to it. The term ‘‘anaphylactoid’’
as distinct from ‘‘anaphylaxis’’ refers to a non-antibodymediated
degranulation of mast cells, releasing histamine (and tryptase).
Clinically indistinguishable from anapylaxis, both processes
involve the release of large amounts of histamines—just from different
underlying mechanisms. ‘‘Anaphylactoid syndrome of pregnancy’’
is thus a misnomer for two reasons. First, the best working hypothesis
for AFE remains a maternal immune response to fetal antigen
leaking into the circulation (i.e. one involving antibody). Thus, a nonantibody
response implied by the term anaphylactoid is not appropriate.
Second, since the case series failed to find any evidence for
mast cell degranulation (whether immune on non-immune mediated),
it is premature to assign the disease a name implying this specific
mechanism.