Ultrastructural Changes in the Placental Membrane in Pregnancies Associated with Diabetes

Abstract

Cambios Ultraestructurales en la Membrana Placentaria en Embarazos Asociados con la DiabetesRanjana SUMMARY:Placenta is the most accurate record of the infant prenatal experience. If the placenta is examined minutely after delivery, it provides much insight into the prenatal health of the baby and the mother. The weight of placenta is higher in diabetic pregnancy in comparison to the normal pregnancy. To study the cellular changes that might contribute to more weight of placenta in diabetic pregnancies, light microscopic and electron microscopic analysis was performed. Twenty singleton pregnancies complicated with Gestational diabetes mellitus (12 controlled on diet, 8 controlled on insulin) were selected and compared to control group. Tissue sections were processed and analyzed. The placenta of diabetic pregnancies showed no abnormality on gross observation but light microscopic examination revealed, lesions like syncytial knots, fibrinoid necrosis, villous edema, villous fibrosis and capillary proliferation. Transmission electron microscopic examination (TEM) showed changes in almost all the layers of the placental membrane i.e. synctiotrophoblast, cytotrophoblast, trophoblastic basement membrane and fetal capillaries. These changes were observed in the placenta of both groups of patients whether blood sugar level was controlled by diet or insulin, but to different degree. It indicates that control of hyperglycemia only partially prevents the development of placental abnormalities which must be due to some other constituent factor of diabetic state. KEY WORDS: Gestational diabetes mellitus; Transmission electron Microscopy; Placental membrane. INTRODUCTIONDiabetes is now a major health concern in our society. According to the centers for disease control and prevention, from 1980 to 2005, the crude incidence of diagnosed diabetes has increased from 3.3 per 1000 to 7.4 per 1000 i.e by 124%. Studies suggest that the prevalence of diabetes mellitus (DM) among women of childbearing age is increasing due to more sedentary lifestyles, changes in diet, and the virtual epidemic of childhood and adolescent obesity that is presently evolving in India. Gestational diabetes mellitus (GDM) is defined as glucose intolerance of variable degree with onset or first recognition during pregnancy. Abnormal maternal glucose tolerance occurs in 3-10% of pregnancies in Indian population (Dutta, 2004).Maternal diabetes mellitus exposes the fetus to the risk of macrosomia, congenital malformations, intrauterine growth retardation and difficult labour (Fletcher, 1981). The neonatal metabolic problems are hypoglycemia and hypocalcaemia. All these conditions may be related to reduced placental perfusion and decreased arterial oxygen saturation attributing to placental abnormalities. Therefore, the placenta of diabetic women has gained much interest showing several pathological changes.In term pregnancy, the placental membrane is extremely thin, approximately 0.002mm in thickness, separating fetal blood from maternal blood. The five layers...