Introduction: Placenta previa is abnormally located either very close to or covering the internal os of the uterine cervix and may interfer with normal fetal growth and development. The incidence of placenta previa during second trimester is 5%, but near the end of pregnancy more than 90% of these cases will not be placenta previa as observed by trans-vaginal ultrasonography. Recent evidence has suggested that disproportion between pro‑angiogenic and anti‑angiogenic factors may have a principal role in the pathogenesis of placenta previa.
Aim of the Work: The present study aimed at studying the morphological features, histological and immunohistochemical changes (vascular endothelial growth factor [VEGF] and connective tissue growth factor [CTGF]) of placenta previa compared to normal placenta.
Materials and Methods: Thirty placentas were brought from term pregnant women undergoing delivery, 15 healthy normally situated control placentas and 15 placenta previa. Gestational age, neonatal birth weight and delivery mode were obtained. Maternal, placental and fetal parameters were statistically assessed. Placentas were then subjected to morphological, histological and immunohistochemical studies.
Results: Placenta previa was associated with higher incidence of cesarean section and lower neonatal birth weight. Histological examination of placenta previa showed morphological changes indicative of increased syncytial knots, villous agglutination and infarcts, distal villous hypoplasia, and vascular mural hypertrophy of stem villi. Placenta previa revealed significant decrease in the expression of CTGF compared to control placentas. Assessment of histomorphometric data were carried out using “ImageJ 1.50i" program. The data were statistically analyzed using IBM SPSS advanced statistics version 26.
Conclusion: Angiogenic factors appeared to have no role in pathogenesis of placenta previa. Moreover, the risk caused by persistent placenta previa necessitates further studies of both umbilico-placental and utero-placental circulations.