• Immunotherapy for pollen or house dust mite allergy

Pregnant women can continue desensitisation (specific immunotherapy) if the therapy is tolerated without any complications. This is stated in the guidelines of the professional allergy associations. If the patient is being treated for a pollen or house dust mite allergy, most doctors will decide against continuing the therapy due to the risk of anaphylactic shock with circulatory collapse, which is a potential adverse effect. It occurs in extremely rare cases, usually at the beginning of therapy (if at all), and not during ongoing, well-tolerated therapy. Nevertheless, such a reaction could jeopardise the oxygen supply to the foetus. Since specific immunotherapy is not urgently needed for the health of the mother, it is better to minimise the risk.

Furthermore, many allergen extract producers recommend in their information leaflets that therapy be discontinued in the event of pregnancy, even though there has been no indication to date of any harm caused to the embryo by the extracts.

• Immunotherapy for bee or wasp venom allergy

The situation is different if you are being treated for a life-threatening bee or wasp venom allergy. It may be advisable in this case to continue with specific immunotherapy if it is well tolerated. After all, the insect sting itself can trigger anaphylactic shock. Successful specific immunotherapy significantly reduces this risk. In the end, the decision should be made together with the doctor on a case-by-case basis.

As for whether specific immunotherapy can be started during pregnancy, the authors of the guidelines take a very clear position: an existing pregnancy is generally considered a contraindication, and therefore therapy should not be started.

What if the woman is not yet pregnant but is trying to conceive? Can she start specific immunotherapy if she suffers from severe allergy symptoms? Again in this case, family planning should be completed before embarking on desensitisation therapy. Even so-called short-term therapy for hay fever, which consists of only four injections, is not an option, since the treatment must be repeated the following year.

However, there is a possibility that specific immunotherapy will no longer be necessary after the pregnancy. This is because hormonal changes can cause the allergy to become milder or go away.