The third dose of the New Crown vaccine is not allowed in pregnancy. The New Crown Vaccine is a new type of vaccine, its specific side effects are not very clear, some people will have different reactions after injection. If a third dose of the vaccine is given at this time, it is more likely to stimulate a metabolic reaction in the body leading to allergies. Pregnant women may experience symptoms such as rash, itching, diarrhea, etc. In severe cases, the normal growth and development of the fetus may be affected. There is even a risk of preterm labor and miscarriage, which will adversely affect the health of the pregnant woman and the fetus. The placental barrier is the easiest human immunization barrier to pass through. If an adverse reaction occurs because of vaccination, it may affect the health of the pregnant woman and the fetus. Pregnant women are in a special physiological state and their body immunity will be lower than when they are not pregnant, thus leading to poor tolerance of antigens by the body. Therefore, it is best not to give the third dose of New Crown Vaccine when pregnant. It is recommended that pregnant and breastfeeding women postpone vaccination. For details, consult your doctor and vaccinate under his/her supervision.