Clinical and epidemiological features of syphilis and the course and outcome of pregnancy were studied in 155 pregnant women infected with syphilis; 95 (61%) women were unemployed, 47% were unmarried. Syphilis proceeded without clinical manifestations in 121 cases (78%). Discordant results of complement fixation (Wassermann) test, precipitation test, Treponema pallidum immobilization test, and fluorescent antibody test were observed in 22 (14%) of the women. Pregnancy pathology was observed in 75 cases (48.8%) and more often appeared as anemia in 49 (31.5%), stillborn in 46 (29.8%) and toxicosis in 44 (28.4%). Fetal ultrasonic stigmas of infection were evident in 23 cases (49%). There was distension of the brain ventricle system and hepatomegaly each in 1 case (2%), transvascular infiltration of liver in 2 cases (4%), dilation of intestinal loops, gastromegaly, ventriculomegaly and petrifaction in lungs each in 1 case; ultrasonic changes in vessels of organs: of the liver in 4 cases (8%), intestines and stomach in 16 cases (32%), lungs in 4 cases (8%), kidneys in 10 cases (21%) and of the ventricular system in 9 cases (19%). Fetus development retardation was revealed in 3 cases (6%), fetal hypoxia in 1 (2%), hypohydrosis in 2 (4%) and hydropsy in 1 case (2%). The pregnancy pathology in women with syphilis was considered not pathognomonic.