ANAPHYLAXIS AND PREGNANCY
F. Estelle R. Simons, MD, FRCPC
Anaphylaxis during the first three trimesters of pregnancyis similar to anaphylaxis in the general population with regard to etiologies(eg. food, medication, insect sting), clinical criteria for diagnosis, differential diagnosis, and management of the acute episode. It is important to note, however, that in pregnant women, anaphylaxis symptoms and signs often include uterine cramping, lower back pain, and preterm labor. Additionally, if allergen immunotherapy is indicated, initiation is typically deferred during pregnancy,and if immunotherapy is ongoing, allergen dose increases are typically deferred during pregnancy.
During labor and delivery, anaphylaxisis uncommon,but potentially catastrophic because it can result in death or hypoxic-ischemic encephalopathy in both the mother and the fetus. Typical etiologies include medications such as beta-lactam antibiotics (administered to prevent group B streptococcal infection in the neonate), oxytocin, and muscle relaxants, and natural rubber latex. The differential diagnosis includes amniotic fluid embolism syndrome and other disordersthat potentially cause maternal respiratory and/or cardiovascular compromise.
During labor and delivery, management of anaphylaxis is similar to management of anaphylaxis in the general population, with three major caveats: 1) supplemental oxygen is critically important; 2) the mother should be positioned on her left side rather than on her back, so that the weight of the gravid uterus does not obstruct venous return to her heart; and
3) continuous electronic monitoring of fetal heart rate and continuous non-invasive monitoring of maternal blood pressure, heart rate and oxygenation are necessary.
Through anaphylaxis risk assessment and risk management in all women of child-bearing age, allergy/immunology specialists playa unique role in prevention of anaphylaxis in pregnancy, including potentially catastrophic anaphylaxis episodes during labor and delivery.
REFERENCES:
Simons FER, Ardusso LRF, Bilo MB, El-Gamal YM, Ledford DK, Ring J, Sanchez-Borges M,
Senna GE, Sheikh A, Thong BY, for the World Allergy Organization. World Allergy Organization guidelines for the assessment and management of anaphylaxis. WAO Journal 2011;4:13-36.
Simons FER, Ardusso LRF, Bilo MB, El-Gamal YM, Ledford DK, Ring J, Sanchez-Borges M,
Senna GE, Sheikh A, Thong BY, for the World Allergy Organization (includes both Summary
and full Guidelines). World Allergy Organization guidelines for the assessment and management
of anaphylaxis. J Allergy Clin Immunol 2011;127:587-93.e22.
Schatz M, Simons FER, Dombrowski MP: Anaphylaxis in pregnant and breastfeeding women.
In: Basow DS (editor): UpToDate. Waltham, MA: UpToDate, 2011.