Objective. To study the role of Doppler velocimetry of the umbilical andmiddle cerebral arteries, represented by the cerebroplacental ratio, andamniotic fluid volume in the prediction of adverse fetal outcome in post-termpregnancies. Design. A prospective case control study. Setting. CairoUniversity Teaching Hospital for Obstetrics and Gynecology. Egypt. Subjects.50 pregnant patients divided into two groups; Group1: This group included 25pregnant ladies with gestational age of 41 weeks attending the casualitydepartment in labour or in prodroma of labor. Group 2: This group included 25pregnant ladies with gestational age of 41 weeks not in labor and reaching thehospital for ANC, who were selected for termination based on the biophysicalprofile and poor Doppler indices or CTG changes. Interventions. All patientswere submitted to antenatal fetal surveillance tests including modifiedbiophysical profile (MBPP) which consists of the non-stress test (NST),amniotic fluid index (AFI), and color Doppler velocimetry of fetoplacental andfetal vessels including MCA PI, UA PI, and CPR. Main outcome measures. Theaccuracy of cerebroplacental ratios (the middle cerebral artery PI divided by theumbilical artery PI) and amniotic fluid volume as a means of predictingintrauterine fetal distress and adverse perinatal outcome in post-termpregnancies. Results. Cerebroplacental ratio show highest sensitivity (95%) incomparison with other parameters, so it is a good test to reassure theobstetricians of the fetal well being. Prominent changes in AFI (i.e. <50%increase or decrease) is not associated with adverse perinatal outcomeirrespective of the rate of change provided that the final value remains >5.0 cm.A significant association with FHR decelerations and presence of meconium isproved to exist when AFI is <5.0 cm. Conclusion. The addition ofcerebral/umbilical ratios to antenatal surveillance protocols is expected toimprove the perinatal outcome. It should be tried in the various high riskpregnancies whenever uteroplacental insufficiency is suspected