Objective — to identify the prognostic criteria for obstetric and perinatal complications on the basis of an analysis of anamnestic data and the specific features of the course of current pregnancy in patients with morphologically verified intrauterine infection (IUI). Subject and methods. A total of 327 pregnant women enrolled in the study by continuous sampling were examined. Group 1 consisted of 130 patients, in whom IUI was verified by histological placental examination (a study group). Group 2 included 197 pregnant women whose placentas displayed no inflammatory changes (a comparison group). Clinical, laboratory, instrumental, microbiological, and pathological examinations were performed. Results. The women with morphologically confirmed IUI showed the features of their current pregnancy: the latter and early neonatality were more commonly complicated. The criteria for IUI during pregnancy can be considered to be a combination of the following factors: a compromised obstetric/gynecological history, cervicitis, recurrent threatened miscarriage, a number of echographic signs (abnormal amount of amniotic fluid, placental structural changes), uteroplacental circulatory disorders, and prothrombotic hemostasis. Miscarriage and preterm birth were significantly more frequently recorded in the study group. Conclusion. Identification of clinicoanamnestic, microbiological, pathological, and instrumental diagnostic criteria of IUI during pregnancy will be able to predict obstetric and perinatal complications of pregnancy and to timely use therapeutic and preventive measures to reduce perinatal losses. The authors declare no conflicts of interest.