Bidzina Kulumbegov
Allergist/Immunologist. MD. Clinical Director of the Center of Allergy and Immunology.
Immunological Tolerance and the Management of Allergic Diseases During Pregnancy
Clinical Review and Epigenetic Perspectives
During pregnancy, the mother’s body undergoes a fundamental immunological reconfiguration. In this period, the immune system maintains a delicate balance between tolerance toward the fetus and protection against environmental pathogens. Disruption of this balance often leads to the exacerbation of allergic diseases or the manifestation of new pathologies. Understanding the mechanisms behind this adaptation is essential for optimal management.
Mechanisms of Immunological Adaptation
During pregnancy, hormones — estrogen, progesterone, and cortisol — drive the transformation of the immune system from a pro-inflammatory response to a tolerant one. In many patients, conditions like asthma or urticaria (hives) go into remission during pregnancy due to the effects of endogenous cortisol; however, in approximately ⅓ of patients, symptoms worsen. Recognizing how these immunological shifts affect respiratory conditions is particularly important.
Hormone | Effect on Allergy |
Estrogen | Increase in TH2 cytokines — possible exacerbation of atopy |
Progesterone | T-cell suppression — promotes tolerance |
Cortisol | Anti-inflammatory — often reduces symptoms |
Differential Diagnosis of Rhinitis and Bronchial Asthma
Approximately 20–40% of pregnant women suffer from nasal congestion. Clinicians must distinguish allergic rhinitis from so-called pregnancy rhinitis, which is caused by hormonal influences and increased blood volume — not allergens.
Symptom | Allergic Rhinitis | Pregnancy Rhinitis |
Sneezing/Itching | Pronounced | Rare |
Discharge | Watery | Mucous, thick |
Duration | Exposure-dependent | Disappears within 2 weeks after childbirth |
Approximately 1 in every 100 pregnant women suffers from asthma. The core principle: untreated asthma is far more dangerous to the fetus than the treatment itself. During an asthma exacerbation, hypoxemia poses a direct threat to the fetus; therefore, inhalation therapy is not only permitted but mandatory.
Epigenetics and Fetal Immune Programming
Pregnancy represents a critical window for the development of the child’s immune system. Studies have shown:
- Omega-3: Demethylation of the FOXP3 gene, enhancement of Tregs, reduction of atopy risk.
- Probiotics: Demethylation of the IL-10 gene, enhancement of the anti-inflammatory response.
- Diverse diet: Consuming a varied diet (including milk, peanuts, and gluten) reduces the risk of allergies in the child. Artificial dietary restriction is only warranted in cases of confirmed maternal allergy.
Practical Recommendations and Specialist Referral
A 2025 study by the American College of Allergy, Asthma & Immunology (ACAAI) revealed significant gaps in care: ¼ of surveyed obstetrician-gynecologists never refer pregnant patients to an allergist.
An allergist’s intervention is critical for:
- Confirming drug allergies (to ensure the safe use of antibiotics required during childbirth).
- Achieving optimal asthma control (prevention of hypoxia).
- Managing chronic urticaria.
- Environmental control: Practices such as nasal irrigation with saline solution, using allergen-proof encasements, utilizing HEPA filters, and keeping windows closed during pollen seasons can significantly reduce the need for medications.
Conclusion
Allergological consultation during pregnancy planning and throughout its course is an integral part of modern prenatal care. Adequate management — comprising symptom control, appropriate pharmacotherapy, and a diverse maternal diet — ensures both the mother’s comfort and the immunological well-being of the fetus.