Anaphylaxis in pregnancy – a condition that poses risks for both the mother and the fetus – now has published guidelines, thanks to work done at the University of California in San Diego and the Kaiser Permanente Medical Center. Guidelines previously did not exist. The authors point out that just as the general incidence of anaphylaxis is increasing, it is also increasing in pregnant women.
During the three trimesters of pregnancy the causes of anaphylaxis are the same as in the general population. In order of decreasing frequency these are: foods, stinging insects, medications, biologic agents (X-ray dyes) and latex. At the time of labor and delivery the causes shift. Again in the order of decreasing frequency they are: antibiotics, latex, neuromuscular blockers (used as part of anesthesia), oxytosin (used to stimulate contractions of the uterus), local anesthetics and transfusion of blood or blood products.
The symptoms of anaphylaxis in pregnancy are the same as in non-pregnant women, with a few caveats, and include itching, rash, swelling, throat constriction, wheezing, nausea, vomiting, diarrhea, tachycardia and low blood pressure. Symptoms somewhat unique to pregnancy include severe vulvar and vaginal itching, low back pain and premature labor contractions.
Treatment of anaphylaxis in pregnancy is the same as for non-pregnant women with some special considerations. Adrenalin (epinephrine) is still the mainstay of therapy. It is critical to give enough adrenalin to maintain the mother’s systolic blood pressure above 90 (and thereby the fetal blood flow).
IV fluids are used as in all people with anaphylaxis, as is oxygen – except in pregnant patients high levels, even 100 percent oxygen, are recommended. Recumbency is part of treatment of all anaphylaxis, but it is best for the pregnant woman lie on her left side so as to better ensure uterine blood flow.
Finally, if the anaphylaxis is protracted or severe, emergency C-section delivery of the infant is indicated.