The Doppler cerebroplacental ratio and perinatal outcome in intrauterine growth restriction

OBJECTIVE: Our purpose was to determine whether the Doppler cerebroplacental ratio predicts perinatal outcome in fetuses at risk for intrauterine growth restriction. STUDY DESIGN: The middle cerebral and umbilical artery pulsatility index Values were measured in 203 fetuses at risk for intrauterine growth restriction, of which 123 were delivered <3 weeks after the last Doppler examination. Perinatal outcome was categorized as (1) birth weight <10th percentile, (2) birth weight <5th percentile, (3) perinatal complications (meconium-stained fluid, cesarean section for fetal distress, 5-minute Apgar score <7, perinatal death, neonatal intensive care unit stay >24 hours, hypoglycemia, or polycythemia), (4) birth weight <10th percentile plus complications, and (5) birth weight <5th percentile plus complications. The cerebroplacental ratio (middle cerebral artery pulsatility index divided by umbilical artery pulsatility index) values were expressed as multiples of the normal median. Receiver-operator characteristic curves (sensitivity vs false-positive rates) were plotted for the prediction of each category of perinatal outcome and the areas under the curves were determined. Stepwise logistic regression analyses were used to determine whether the cerebroplacental ratio improved outcome prediction over umbilical artery Doppler imaging alone. RESULTS: There was a statistically significant increase in perinatal morbidity and mortality in cases with an abnormal cerebroplacental ratio. The areas under the receiver-operator curves characteristics for the prediction of perinatal outcome with use of the cerebroplacental ratio were statistically very significant. For birth weight <10th percentile we noted P < .001,with P < .0001 for each of the other 4 outcome categories. As shown by regression analyses, the cerebroplacental ratio appeared to improve the prediction of perinatal outcome compared with umbilical artery velocimetry alone. An interesting finding was that the cerebroplacental ratio did not appear to correlate significantly with outcome in fetuses at >34 weeks. CONCLUSION: Doppler identification of the fetal "brain-sparing" effect strongly predicts outcome in fetuses at risk for intrauterine growth restriction. The brain-sparing effect predicted perinatal problems only in fetuses <34 weeks' gestation at the Doppler examination.