Anaphylaxis Treatment in Pregnant Women

Immediate Management

The American College of Hematology recommends administering intramuscular epinephrine immediately at 0.3-0.5 mg (1:1000 concentration) into the anterolateral thigh for anaphylaxis in pregnancy, with no absolute contraindications to its use, including pregnancy 1, 2, 3, 4
Stop the IV FCM infusion immediately upon recognition of anaphylaxis, as recommended by the American Journal of Hematology 1, 2, 3
Inject epinephrine 0.3-0.5 mg intramuscularly (0.01 mg/kg, maximum 0.5 mg) into the vastus lateralis muscle in the anterolateral thigh, as suggested by Radiology 2, 3, 4
Repeat epinephrine every 5-15 minutes if symptoms persist or worsen, according to Praxis Medical Insights 3, 4
Do not delay epinephrine administration to give antihistamines or corticosteroids first, as delay is directly associated with increased mortality and biphasic reactions, warned by Radiology and Praxis Medical Insights 2, 3, 4

Consider IV epinephrine infusion (1:10,000 concentration, 4.0 μg/mL at 1-4 μg/min, maximum 10 μg/min) for protracted anaphylaxis unresponsive to multiple IM doses, as recommended by Praxis Medical Insights 3, 4
Administer additional IV fluid boluses as needed, according to Praxis Medical Insights 3, 4
Consider vasopressors (dopamine) for refractory hypotension despite volume replacement and epinephrine, suggested by Praxis Medical Insights 4

Observe until all signs and symptoms completely resolve, as recommended by Praxis Medical Insights 3, 4
Extended observation of at least 6 hours is warranted for severe anaphylaxis or patients requiring more than one dose of epinephrine, as these are risk factors for biphasic reactions, warned by Praxis Medical Insights 3, 4
Transfer to emergency department or intensive care for continued monitoring, according to Praxis Medical Insights 3, 4

Never delay epinephrine while administering antihistamines or corticosteroids first, as this is the most dangerous error, warned by Radiology and Praxis Medical Insights 2, 3, 4
Never rely on antihistamines alone to treat cardiovascular collapse or respiratory distress, cautioned by Praxis Medical Insights 4
Never use first-generation antihistamines or vasopressors as initial treatment for what may be a minor infusion reaction, as they can exacerbate hypotension and convert minor reactions into serious adverse events, advised by American Journal of Hematology 1

True anaphylaxis from IV iron is exceedingly rare (<1:200,000 administrations) and must be distinguished from complement activation-related pseudo-allergy (CARPA), which is more common and self-limited, according to American Journal of Hematology 1, 5, 6
Features of true anaphylaxis include systemic hypotension, wheezing or respiratory stridor, peri-orbital edema or angioedema, gastrointestinal pain, and urticaria with cardiovascular or respiratory compromise, as listed by American Journal of Hematology and Radiology 1, 2, 5, 7

Prescribe epinephrine auto-injector for potential future reactions, recommended by Praxis Medical Insights 4
Refer to allergist for evaluation and identification of safe alternative iron formulations, suggested by Praxis Medical Insights 4
Document the reaction thoroughly and list FCM as a contraindication for future use, advised by American Journal of Hematology 1
Consider alternative IV iron formulations (ferumoxytol, LMWID, FDI) if future IV iron is needed, as these have lower rates of hypersensitivity reactions, according to American Journal of Hematology 6