The causes of urticaria in late pregnancy may be infection, allergy, mental and endocrine factors, etc. The causes of urticaria are complex, and most of them are difficult to identify the causes of the disease 1. Infection: Urticaria can be induced by bacterial, viral, fungal, intestinal parasites and Helicobacter pylori infections during pregnancy. 2. Allergy: If pregnant women in late pregnancy are allergic to animal dander, dust mites, fungal spores, etc. in the environment, or to food such as fish, shrimp, crab, milk, eggs, etc., the contact with these substances will cause an allergic reaction of the organism, triggering urticaria. 3. Mental and endocrine factors: due to endocrine changes, mental tension, anxiety, etc., pregnant women in late pregnancy are prone to urticaria. If urticaria occurs in late pregnancy, you should go to the hospital in time to receive professional treatment, do not delay.