MASSIVE SUBCHORIAL THROMBOSIS OF THE PLACENTA AND PREGNANCY OUTCOME

Objective. To make a clinical and anatomic analysis of the etiology, clinical course, and outcomes of massive subchorial thrombosis (MSCT), a rare type of uterine-placental circulatory disorders. Subjects and methods. Eight cases of MSCT during singleton pregnancy, including 4 cases of intra- and antenatal fetal deaths at 18—31 weeks’ gestation and 4 cases of live babies born at 32 and 37—38 weeks, were analyzed. Clinical and anatomic comparisons were made to determine the value of the placenta in critical condition and antenatal fetal death. While examining the placenta, the investigators determined its weight and placental-fetal index, the state of the intervillous space, villous tree, villous vessels, and trophoblast. Results. MSCT in the placentas of intranatal dead fetuses occupied as high as four-fifths of the chorial plate area, by spreading to the basal plate and compressing the villous tree. MSCT in the neonatal placentas appeared as solitary subchorial hematoma or subchorial fibrin masses that occupied as high as half of the chorial plate area. The neonatal infants with MSCT showed fetal growth retardation syndrome and low-weight placentas with pronounced compensatory changes in the villous chorion. Thrombotic masses were composed of unaltered, hemolyzed red blood cells and fibrin of various ages, which was arbitrarily classified as mature (6—24-hour) and old (more than 24—48-hour). The chorial plate in the area of MSCT showed fibrinoid necrosis. Conclusion. The poor fetal outcome of MSCT is due to the low-weight placenta and physiological immaturity of compensatory processes. Prolonged MSCT makes it possible to diagnose this critical condition of the fetoplacental unit, to perform appropriate therapy, and to generate an idea of further pregnancy management.

placenta, massive subchorial thrombosis, fetal death, neonatal death