Anaphylaxis in Pregnancy

Anaphylaxis during pregnancy is a relatively rare but potentially life-threatening event that can be devastating to the mother and the infant. Etiologies during the first three trimesters are similar to anaphylaxis in nonpregnant individuals and include foods, medications, insect stings, latex, and exercise. Etiologies during labor and delivery include most commonly antibiotics (beta-lactams) used for infection prophylaxis, oxytocin, and perioperative agents. In addition to typical cutaneous, respiratory, and gastrointestinal symptoms of anaphylaxis, unique signs and symptoms of anaphylaxis during pregnancy include intense vulvar and vaginal itching, low back pain, uterine cramps, fetal distress, and preterm labor. Prevention of anaphylaxis can be achieved by doing a prepregnancy risk assessment for anaphylaxis in all women of childbearing age and implementing risk reduction strategies. This includes performing appropriate skin testing, challenge tests, and implementing immunotherapy prior to pregnancy. It also includes confirming the etiology of prior systemic reactions/anaphylaxis. A personalized anaphylaxis emergency action plan should be developed, medical alert jewelry/identification should be worn, and injectable epinephrine should be prescribed and be available at all times. During pregnancy, skin testing, challenge tests, and initiation of immunotherapy are almost always deferred to avoid iatrogenic risk. Patients on maintenance immunotherapy may continue after risk communication, though doses should generally not be increased during pregnancy. Management of anaphylaxis during pregnancy includes injecting intramuscular epinephrine promptly, positioning the mother on her left side to improve venous return to the heart, providing high-flow supplemental oxygen, continuous monitoring, and maintaining systolic blood pressure at 90 mm Hg or higher to maintain perfusion of the placenta. Cardiopulmonary resuscitation and emergency cesarean delivery should be performed when indicated. Prospective studies of anaphylaxis during pregnancy and following women at higher risk for anaphylaxis (i.e., such as those on immunotherapy or with known food, drug, or insect sting allergies) are needed to help advance optimal management strategies.