Background. Intrauterine infection remains the main problem of perinatology. Early diagnosis of such infection causes enough difficulties and requires improvement. This study is devoted to the problem of predicting non-immune fetal hydrops if a woman is infected with parvovirus B19 in the II trimester of pregnancy.Objectives: to improve the diagnosis of non-immune fetal hydrops on the basis of changes in the α-fetoprotein (AFP) value in maternal blood during parvovirus B19 infection .Materials and methods. Serial AFP determination in blood serum of pregnant women infected with parvovirus B19 (n = 16) at 18–20–22 weeks of pregnancy was carried out. Biochemical analysis of AFP in amniotic fluid was performed after prenatal invasive examination in fetuses with non-immune hydrops. The obtained data were compared with similar indicators of pregnant women from the control group (n = 16) with a normal course of pregnancy in the II trimester. Transabdominal amniocentesis was performed under ultrasound control at 16–20 weeks of gestation for fetuses with non-immune hydrops. Determination of the AFP value in the blood serum of pregnant women in the II trimester was performed with a chemiluminescence immunoassay analyzer.Results. It was established that the AFP level in maternal blood reaches and exceeds threshold values (2.6 ± 0.05 MoM) on average 2.5 ± 0.5 weeks before the manifestation of severe fetal anemia in infected fetus with non-immune hydrops (r = 0.768, p < 0.001). That is, a sharp AFP increase in the blood of a pregnant woman infected with parvovirus B19 is a predictor of the development of non-immune fetal hydrops due to parvovirus B19 infection.Conclusions. The described method has proven to be highly effective, it is allows reducing the frequency of ultrasound examinations for infected women, because the fetus is not always infected from an infected mother. This technique can be used as a predictor of intrauterine parvovirus B19 infection in the II trimester, which will allow the development of new approaches to the early diagnosis of non-immune fetal hydrops, as well as contribute to timely intrauterine hemotransfusion.