Background: Although using Doppler ultrasonography of umbilical structures is a common method for predicting prenatal adverse outcome, recent studies have proposed the importance of middle cerebral artery (MCA) Doppler assessment for antenatal monitoring. The aim of the present study was to compare alterations in the fetalMCAversus umbilical artery (UA) pulsatility indices (PI) in complicated pregnancies by fetal growth restriction (FGR). Methods: A cohort study was carried out in Yas Hospital (Tehran, Iran) in 2016. One hundred fifty pregnant women in third trimester with estimation of FGR participated in the study. Transabdominal ultrasound was performed to determine fetal weight. After birth, all neonates were divided into 2 groups: small for gestational age (SGA) and non-SGA.We compared the values of UA and MCA Doppler in predicting SGA. Data were analyzed with t-test and Chi-square test. Results: After delivery, 126 mothers had SGA while 24 subjects had non-SGA neonates. Unlike UA PI, MCA artery PI of the SGA and non-SGA groups were significantly different (p=0.062 for UA PI comparison; p=0.0001 for MCA PI comparison). Of the 126 cases, there was decreased MCA PI in 40.5% of fetuses and increased UA PI in 22.2% of fetuses. There were significant differences in both sensitivity and specificity for MCA PI versus UA PI (p=0.014 for sensitivity; p=0.009 for specificity). Conclusion: Results showed that of all the SGA cases, a decrease in MCA PI was more notable than changes in UA PI. Sensitivity, specificity and prediction of SGA for MCA PI were higher than those for UA PI.