Anaphylactic reactions are rare events but may be fatal in as many as 10% of cases.
28 Antibiotics, anti-inflammatory agents, oxytocin, anesthetic agents, blood products, colloid solutions, and latex exposures are some of the most common causes of anaphylaxis during pregnancy. Anaphylaxis is a series of events that occur in a sensitized individual on subsequent exposure to a specific antigen. It classically refers to an immunoglobulin (Ig) E-mediated, type I hypersensitivity response, produced by the release of antigen-stimulated mast cells and basophil mediators (eg, prostaglandins, leukotrienes, histamine, tumor necrosis factor alpha). The latter may result in a life-threatening systemic reaction with urticaria, angioedema, hypotension from severe vasodilation, increased vascular permeability with third spacing, airway obstruction from edema, and multiorgan system failure. Anaphylactic reactions may also be non-IgE-mediated responses (ie, reactions to IV immunoglobulins, dialysis circuit membranes, dextrans, and iron). In the past, the latter were referred as anaphylactoid reactions; however, this term is no longer recommended.
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