Objectives: Cerebroplacental ratio (CPR) is an indicator for predicting adverse perinatal outcomes during pregnancy. The aim of this study is to evaluate the relationship between CPR and some factors such as diabetes, gestational hypertension, body mass index (BMI), PAPP-A and drug use. Methods: In this study, the CPR was evaluated in 230 pregnant women who were at 28-38 weeks of gestational age with sigleton pregnancy and EFW of fetus is more than 3 percentile In this study, a number of factors such as diabetes mellitus, gestational hypertension, BMI, PAPP-A, and drug use were investigated. Data were analysed using SPSS software, version 19. Results: There was no significant relationship between PAPP-A and CPR in our study. There was no significant relationship between BMI and CPR in our study. Among 230 pregnant women entered this study, 31 women had diabetes. Of these 31 women with diabetes, 22 persons had normal CPR but, 9 of them had low CPR, which has significant analytic value. Of 230 pregnant women entered this study, 9 women had gestational hypertension, which all of them had Low CPR. Distribution of low CPR in different EFW percentiles, 3-10, 10-25, 25-50, 50-75, 75-95 were 14%,13%,10%, 6%, 6%, respectively, showing the presence of low CPR even in high EFW percentiles, but low CPR were more common in 3-10 EFW percentile. Conclusions: Diabetes and gestational hypertension are two factors that influence the cerebroplacental ratio.