Rubella virus is a virus that does not cause much harm to pregnant women, but is very harmful to children. It is a virus that is transmitted through the respiratory tract and once infected can give lifelong immunity and of course a small amount of reinfection. For adults it may be a symptom of a cold, and probably more people have no symptoms at all. The poor unborn child may be less fortunate and either miscarry or be stillborn, or grow small, or develop congenital rubella syndrome (multi-system involvement of the eyes, ears, and heart). However, the infection is not always teratogenic for the mother’s child, and the teratogenicity decreases as the weeks of pregnancy increase. The rate of fetal infection decreases to 50% and the rate of birth defects decreases to 20% when the mother is infected for the first time before 11 weeks, while the rate of fetal infection decreases to 50% and the rate of birth defects decreases to 20% when the mother is infected for the first time between 16 and 20 weeks. not teratogenic. Therefore, it is critical to determine the timing of rubella virus infection. For example, IgM is a miscellaneous antibody produced by the body’s immune system when the virus first enters the body, and this antibody is relatively weak and has a slightly less protective effect on the body. Lifetime immunity. After a few weeks to a few months, IgM, the miscellaneous army, and IgG, the genuine army, are officially handed over and finally retired from the history. So we say that in the early stages of disease infection, IgM antibodies can be measured from the patient’s blood, while there are two trends in the dynamic detection of IgG antibodies, one from none to more, and one from more to more, in a fourfold increase. Both antibodies are equally important for the diagnostic value of recent rubella virus infection. Some hospitals are wrong to determine maternal infection by testing IgM alone. It is not known that a positive IgM for rubella may be associated with other problems, such as infection with other viruses (EBV, cytomegalovirus, microvirus B19), that patients with autoimmune diseases can have false positives, and that some infected patients or vaccinated patients can have a positive IgM for several years. Therefore, it is not possible to determine that a patient has a recent infection based on a positive IgM alone.