Stereological Analysis of Human Placenta in Cases of Placenta Previa in Comparison with Normally Implanted Controls

Background: placenta previa (PP) is an obstetric complication that can affect ma-ternal and fetal morbidity and mortality. Its prevalence is rising due to cesarean sec-tions. There is no quantitative data of placenta in PP. In this study, quantitative pa-rameters of placenta in cases with PP in comparison with normally implanted con-trols were investigated. Methods: In this quasi experimental study, placentas from pregnancies with PP and normally implanted controls (n=10) were obtained from women who underwent ce-sarean section. Three full-thickness columns of each placenta were sampled using systematic uniform random sampling (SURS). Columns were cut into slices and slices were sectioned with 4 μm thickness. SURS selected sections were stained by Masson’s trichrome. Stereological analysis was done on 8-10 SURS microscopic fields of each section. Absolute volume and volume density of chorionic villi, inter-villous space, syncytiotrophoblast, fibrin and blood vessels in chorionic villi were es-timated in both groups. Statistical analysis was done using Mann Whitney-U test an