Placental pathology in women with gestational diabetes

Background. The aim of this study was to investigate pathologic differences of the placenta in pregnancies complicated by gestational diabetes compared to non-diabetic pregnancies. Methods. Forty singleton pregnancies complicated by gestational diabetes were recruited and compared to 40 consecutive normal pregnancies. A pathologist, blinded to all clinical data, reviewed all histological samples of the placentas. The histological assessment was carried out with regard to the following aspects: fetal vessel thrombosis, villous immaturity, chorangiosis, presence of nucleated fetal red blood cells (NFRBCs), ischemia, infarction, presence of hydropic or avascular villi, lymphohistiocytic villitis and villous fibrinoid necrosis. Results. The presence of degenerative lesions such as fibrinoid necrosis and vascular lesions like chorangiosis was apparent, mainly in the diabetes group. Villous immaturity and the presence of NFRBC as an indication of chronic fetal hypoxia were significantly increased in the placentas of women with diabetes compared with the control group. Fetal/placental weight ratio was significantly lower in the diabetic group. Conclusion. Histological abnormalities were observed more frequently in the diabetic placentas compared to the controls. These findings support the hypothesis that impaired placental function is one of the main reasons for the increased frequency of fetal complications in diabetic pregnancies.