Histomorphological Alterations of Placenta in Normal vs Gestational Diabetes Mellitus Subjects: A Case-control Study

Abstract

Introduction: Gestational Diabetes Mellitus (GDM) during pregnancy leads to gross and microscopic changes in the placenta. These abnormal changes in the placentas are responsible for the foetal hypoxia and increases perinatal morbidity and mortality. The study of placenta helps significantly in understanding the process of foetal development in response to various maternal conditions like GDM. Aim: To observe the gross and microscopic changes of placenta complicated by GDM and comparing the features with normal placenta. Materials and Methods: In this prospective case control study, performed from January 2012 to December 2015, 80 full term freshly delivered placentas were collected from the labour room with prior informed consent. Forty were from uncomplicated pregnancy (control group) and 40 were from pregnancies complicated by GDM (experimental group). Detailed gross and microscopic examinations were done on placentas from both the groups and the results were documented and associated statistically by using the Statistical Package for Social Sciences (SPSS) version 22.0. Results: On gross examination, of 80 placentas (40 from the control group and 40 from the experimental group), those from the experimental group showed significantly higher placental weight, diameter, volume, thickness, and lower foeto-placental ratio than the control group. The p-value for all these parameters was observed to be <0.0005. Similarly, on microscopic examination villous immaturity (p-value <0.0005), oedema (p-value <0.0005), fibrinoid degeneration (p-value<0.0005), chorangiosis (p-value 0.001) and nucleated foetal RBCs inside the capillaries (p-value <0.0005) were noted to be significantly higher in the experimental group. Conclusion: This study shows significant gross and microscopic changes in the GDM placentas, the most significant histological changes noted were the villous immaturity, thickened Basement Membrane (BM) and fibrinoid degeneration which may be attributed to impaired placental functioning and unfavourable perinatal outcomes.