Allergen Immunotherapy (AIT), commonly known as allergy shots, is a long-term treatment designed to desensitize the body to specific allergens like pollen, dust mites, or pet dander. The process involves injecting small, increasing amounts of these substances to help the immune system build tolerance over time. When a woman becomes pregnant, a primary question often arises regarding the continuation of this treatment due to concerns about the developing fetus. Medical consensus provides a clear distinction between continuing an established regimen and initiating a new one during pregnancy.
Continuing Immunotherapy During Pregnancy
For women who were already receiving allergy shots and had reached the maintenance phase prior to conception, continuing the treatment is generally recommended. Continuing AIT at a stable dose is considered safe for both the mother and the developing baby. Retrospective studies have shown no increased risk of adverse outcomes, such as prematurity or congenital malformations, in women who maintained their injections throughout pregnancy.
Since the body is accustomed to the maintenance dose, the likelihood of a severe systemic reaction is low. The dose should not be increased during pregnancy. Some allergists may recommend a slight dose reduction to further minimize the chance of any reaction, even a mild one. Close coordination between the allergist and the obstetrician is recommended to monitor the patient’s health and reaction profile.
Starting New Immunotherapy
Initiating a new course of allergen immunotherapy during pregnancy is strongly discouraged by medical professionals. AIT involves a build-up phase where the allergen dose is gradually increased, and this period carries the highest risk of a systemic allergic reaction. Since the mother’s body is not yet desensitized, the potential for a severe reaction is elevated during this initial phase.
The primary concern is not the allergen itself, but the potential consequences of a severe allergic reaction, or anaphylaxis. Anaphylaxis can cause a drop in blood pressure and restrict the airways, leading to a temporary reduction in oxygen supply for the mother. This decreased oxygen level, known as fetal hypoxia, poses a theoretical risk to the fetus, potentially leading to complications. Therefore, guidelines recommend postponing the start of AIT until after delivery to avoid this high-risk period.
Managing Allergic Reactions While Pregnant
Managing general allergy symptoms during pregnancy is important for maternal well-being, even if AIT is paused. Uncontrolled allergic rhinitis or asthma can complicate pregnancy, making it important to use safe alternative medications. Many over-the-counter oral antihistamines are considered safe, including second-generation options like cetirizine (Zyrtec) and loratadine (Claritin).
Intranasal corticosteroid sprays are often a first-line treatment for persistent symptoms and are also generally considered safe, with budesonide (Rhinocort) being a preferred choice due to extensive safety data. For a systemic reaction during an allergy shot, the protocol for treatment remains the same as for non-pregnant patients. Administering epinephrine to treat anaphylaxis is always prioritized, as the life-saving benefit to the mother outweighs any theoretical risks to the fetus. Uncontrolled anaphylaxis is far more dangerous to the fetus than the administration of epinephrine.
Resuming Treatment After Delivery
After delivery, women can typically return to their pre-pregnancy AIT regimen with the guidance of their allergist. If the treatment was maintained throughout the pregnancy, the woman can usually resume the standard schedule and begin increasing the dose again to continue the desensitization process. If the treatment was paused for several months, a dose adjustment may be necessary before resuming the full maintenance dose.
Allergen immunotherapy is considered safe to continue while breastfeeding. The small amounts of allergen injected do not pass into the breast milk, meaning they pose no risk to the nursing infant. Continuing AIT postpartum can also help manage the mother’s symptoms, which is essential for her ability to care for the newborn. The allergist will determine the appropriate schedule for safely returning to dose increases, depending on the length of the pause and the patient’s individual tolerance.