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Cerebroplacental ratio (CPR) is a reliable predictor of an impaired neonatal outcome. CPR provides information about fetal hemodynamics and the redistribution of fetal blood volume in response to a metabolic change. CPR is defined as the quotient of the Doppler pulsatility indices (PI) of the middle cerebral artery (MCA) and the umbilical artery (UA). If the fetus is in a hypoxic state or growth retardation, the cerebral vessels dilate to maintain blood flow to the brain – brain sparing effect. This is reflected as a decrease in the MCA PI and an increase in the placental blood flow resistance causing an increased UA PI. As a result of the change in perfusion, the CPR is reduced. A CPR of < 1.08 is abnormal and significantly associated with an increased risk of caesarian section due to fetal distress. A borderline CPR value of 1.08 should also prompt follow-up review with a clinical specialist or at a tertiary center. Abnormal blood flow in the MCA or UA should be assessed within its own parameters. CPR should be routinely assessed in IUGR fetuses, monochorionic twin pregnancies, fetal anaemia, reduced fetal movement, estimated fetal weight less than the 10th centile, and preeclampsia or high risk for preeclampsia patients. Integrating CPR into routine doppler studies in clinical practice will help better identify fetuses at risk.