As people’s habits change, the number of people who develop allergic diseases is gradually increasing. During pregnancy, pregnant women are more prone to allergic diseases than normal people because their immune system is suppressed and therefore their resistance is lowered, and those with existing allergic diseases are likely to have aggravation during pregnancy. Allergic diseases are diseases caused by allergic reactions, such as rash, drug fever, contact dermatitis, urticaria, allergic rhinitis, and even laryngeal edema, bronchial asthma and anaphylaxis in severe cases, which can endanger the life of mother and fetus. Therefore, the clinical manifestations of allergic diseases have different degrees of severity, and doctors mostly choose appropriate anti-allergic drugs according to their conditions during treatment. So can anti-allergy drugs be used during pregnancy? If so, what is the safest choice for pregnant women? The common anti-allergy drugs are antihistamines. Antihistamines do not act directly on histamine, but on histamine receptors, and inhibit the metabolic process by blocking the binding of histamine to the receptors, therefore, these drugs are also called histamine receptor antagonists. Since these drugs mainly act selectively on H1 receptors, they are also referred to as H1 receptor antagonists. There are currently three generations of antihistamines. The first generation of antihistamines has obvious drowsiness, sedation and other adverse effects, affecting the daily life and study and work of the users, clinical application gradually reduced; the second generation of antihistamines has no central sedative effect, but has cardiotoxicity; the third generation of antihistamines, such as desloratadine, is the active metabolite of desloratadine in the body and ethyl ester, which is not metabolized by the liver (CYP3A4) directly In 2001, scholars counted 15 cases of hypospadias in the newborns of 2780 pregnant women who took desloratadine during pregnancy registered in the Swedish birth registry. Later scholars found in studies of male rats from embryonic formation to lactation that dexloratadine administration during pregnancy did not result in hypospadias or other androgen-dependent organismal development. It is presumed that the occurrence of hypospadias reported in Swedish hospitals is a random event. However, considering the specificity of pregnancy and the potential risk of hypospadias with desloratadine, most scholars recommend that the first trimester of pregnancy is a sensitive period, and it is best for pregnant women not to use desloratadine, and that it should be used with caution in the middle and second trimesters. So, what should I do if I have an allergic reaction during pregnancy? Generally speaking, for simple itchy skin caused by allergy, calcium gluconate is also very effective and has no effect on the pregnant woman and the fetus. In addition, there are some studies on allergic diseases in our country in ancient times, and you can also visit a Chinese hospital and choose some decoction or wash formula to improve allergic reactions. Some scholars have prepared their own wash formula for allergic rash during pregnancy (composition of the formula: 15g of thornbush, 15g of windbreak, 30g of bitter ginseng, 30g of white ringworm bark, 30g of comfrey) and applied it to the affected area daily after decoction with water, which has achieved very good results, and the external treatment method does not affect fetal development, and the method is convenient and applicable, which is popular among pregnant patients. In conclusion, pregnant women with allergies or allergic diseases should first and foremost try to avoid contact with or stay away from allergens in their daily lives, and secondly, once an allergic reaction occurs, they must visit a hospital and weigh the pros and cons of using medication under the guidance of a doctor, giving priority to topical topical medication, and the physician will choose the appropriate treatment according to the patient’s condition and the period of pregnancy.