Accuracy of the middle-cerebral-to-umbilical-artery resistance index ratio in the prediction of neonatal outcome in patients at high risk for fetal and neonatal complications.
OBJECTIVE
The purpose of this study was to determine the accuracy of the middle-cerebral-to-umbilical-artery resistance index ratio in the prediction of fetal outcome in pregnancies at high risk for fetal and neonatal morbidity and mortality.


METHODS
A prospective controlled nonrandomized study was conducted in the high-risk pregnancy unit of a teaching hospital. The control group was formed by 20 healthy women with uncomplicated singleton pregnancies and healthy children delivered at term. The study group consisted of 115 women referred to the high-risk pregnancy unit because of a variety of pregnancy complications. Longitudinal evaluation of the control group and cross-sectional evaluation of the study group were carried out at different gestational ages by means of duplex Doppler ultrasonography. The main outcome measures were fetal growth retardation, preterm birth, and neonatal morbidity.


RESULTS
The middle-cerebral-to-umbilical-artery ratio remains relatively constant (mean +/- SD 1.33 +/- 0.19) between 27 and 37 weeks. A cutoff value of 1.0 (sensitivity 57.9%, specificity 75.6%, false-positive rate 24.4%) was selected from the receiver-operator characteristic curve analysis. This cutoff value successfully identified a population at significant risk of fetal growth retardation (relative risk 3.07, 95% confidence interval 1.73 to 5.45, exact two-tailed p = 0.0009) and severe neonatal morbidity (Mann-Whitney U = 463.5, two-tailed p = 0.03). The middle-cerebral-to-umbilical-artery ratio was not useful in the prediction of preterm birth.


CONCLUSIONS
A middle-cerebral-to-umbilical-artery ratio of < or = 1.0 identifies a subgroup of patients at high risk for fetal growth retardation and severe neonatal morbidity.
Arias
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Division of Maternal-Fetal Medicine, St. John's Mercy Medical Center, St. Louis, MO 63141.
D000328:Adult; D002536:Cerebral Arteries / Q000502:physiology*; D005260:Female; D005317:Fetal Growth Retardation / Q000453:epidemiology*; D005544:Forecasting; D006801:Humans; D007231:Infant, Newborn; D007232:Infant, Newborn, Diseases / Q000453:epidemiology*; D007234:Infant, Premature; D011247:Pregnancy; D011256:Pregnancy Outcome; D011446:Prospective Studies; D012307:Risk Factors; D012680:Sensitivity and Specificity; D014469:Umbilical Arteries / Q000502:physiology*; D014655:Vascular Resistance