Pregnant women who eat crabs in moderation usually have no effect. If a pregnant woman eats crabs in a small amount in the middle of pregnancy, there is usually no adverse effect. Crabs contain protein, iron and other nutrients, which can provide the fetus and the pregnant woman with the nutrients they need. Since crab is a kind of seafood, it may cause allergy after consumption. If a pregnant woman is allergic to crab, she may have symptoms such as itchy skin, face rash, etc. In serious cases, placenta previa and fetal demise may occur, so allergy sufferers should not come into contact with crab during pregnancy. If a pregnant woman suffers from discomfort after eating crabs, she should consult a doctor in a timely manner, and under the guidance of the doctor, improve the relevant examinations to clarify the cause of the disease and treat the symptoms.