Human parvovirus B19 (B19), discovered by Cossart et al. in 1975 while screening blood donors for hepatitis B antigen, is the only known human pathogenic parvovirus. The target cells for B19 virus infection are human bone marrow progenitor erythrocytes, and the viral receptor is the erythrocyte P antigen. B19 infections occur in late fall, spring, and early summer, and have an almost worldwide distribution. The virus can be transmitted through the respiratory tract and by transfusion of infected blood or blood products, with an incubation period of 6 to 8 days. In children, it can cause infectious erythema; in adult women in particular, it can cause transient polyarthritis or arthralgia; in pregnancy, B19 infection can cause spontaneous abortion and fetal edema or stillbirth; in patients with underlying red blood cell defects such as sickle cell anemia, B19 can cause severe aplastic crisis; persistent microvirus infection can lead to chronic bone marrow disorders and in immunodeficient patients to chronic anemia; and recently B19 infection has recently been reported to be associated with acute hepatitis. The B19 virus has properties that make it difficult to be destroyed by certain physicochemical methods, and B19 infection can still occur after transfusion of blood products treated with certain inactivation methods, and there is no effective way to remove and/or inactivate the virus. Therefore, it is important to screen and detect B19 infection in blood donors and the special populations mentioned above. HPV-B19 infection in women during pregnancy is quite common and is closely related to occupation. Anyone who has frequent close contact with school-age children, such as kindergarten or elementary school teachers, and medical workers, has an infection rate four times greater than that of the average woman. Pregnant women infected with human microvirus B19 can infect the fetus through the placenta, and the rate of intrauterine infection in the fetus is about 33%, resulting in a fetal mortality rate of 9%. It is now believed that human microvirus infection is an important cause of non-immune abortion. Fetuses that are stillborn or aborted due to intrauterine infection with human microvirus B19 are characterized by high levels of edema, often hydrocephalus, pericardial, pleural and abdominal effusions, severe anemia, and hepatosplenomegaly. Animal experiments have shown that human microvirus B19 infection has a significant teratogenic effect and congenital malformations occur mostly in early to mid pregnancy. Microvirus B19 infection affects the fetus, the main site of impact: multiplying in the nucleus of the adult red blood cells of the fetus. 1, the bone marrow red lineage is destroyed and dissolved in the final stage of maturation, which leads to fetal anemia and heart failure. 2, early fetal loss such as spontaneous abortion, stillbirth, fetal non-immune edema. 3. Typical blood picture shows anemia without reticulocytosis, along with common manifestations of viral infection during pregnancy. The risk of spontaneous abortion and fetal mortality in pregnant women with initial B19 virus infection ranges from 8% to 14%; the risk level is related to the gestational week of infection: if the infection occurs within 20 weeks of gestation, the fetal abnormality rate is high and the fetal mortality rate is about 16%; if the infection occurs in the middle of pregnancy, the fetal edema rate is about 3%. Although the incidence of fetal abnormalities due to B19 virus infection during pregnancy is not high, when they do occur they are usually fatal. Recent studies have shown that B19 viruses are closely related to pediatric Kawasaki disease and may be associated with connective tissue diseases such as systemic lupus erythematosus. Maternal human microvirus B19 infection does not always result in intrauterine fetal infection or death. The status of the pregnant woman, including cellular immunity, specific IgG level and gestational week, has a great impact on whether intrauterine infection or damage occurs in the fetus. If the pregnant woman has a certain level of specific antibodies against human microvirus B19, it can have a protective effect on the fetus and reduce the damage of HPV-B19 infection or make The fetus is protected from the risk of HPV-B19 infection. However, 50% of pregnant women who are infected with HPV-B19 do not produce specific antibodies. ELISA, PCR, and other tests on fetal blood, other tissue specimens, or intrauterine amniotic fluid can determine whether there is an intrauterine human SIV B19 infection. There is no specific antiviral treatment for human microvirus B19 infection, for pregnant women with confirmed viral infection, ultrasound and serum ATP should be performed, if the ultrasound shows normal amniotic fluid volume, no edema or ascites in the fetus, ATP is also normal, continue monitoring for 14 weeks and then stop, if indicated, under the guidance of ultrasound to perform umbilical cord puncture to obtain fetal blood specimens or amniotic fluid for fetal karyotype, human microvirus B19 The fetal karyotype, DNA, serum specific antibodies IgG and IgM will be examined. If intrauterine infection is diagnosed, immunoglobulin therapy or intrauterine blood transfusion may be administered and monitored intensively. If the pregnancy has reached 34 weeks of gestation with increased fetal edema and abnormal NST, early termination of pregnancy should be considered.