Fetal cerebellar growth unaffected by intrauterine growth retardation: a new parameter for prenatal diagnosis.

Nineteen pregnant women with a clinical suspicion of intrauterine growth retardation and with gestational age confirmed by early ultrasound examination were referred to our departments for sonographic evaluations. Multiple biometric parameters were obtained, including the transverse cerebellar diameter by use of the electronic calipers of the machine. A prenatal diagnosis of intrauterine growth retardation was made in all cases based on: (1) the transverse cerebellar diameter being consistently correlated with gestational age as predicted by the last menstrual period, whereas most of the other measurements were consistently discrepant with the transverse cerebellar diameter by more than 2.5 weeks (i.e., more than 2 SD above the mean), and (2) the estimated fetal weight of all fetuses being equal to or less than the tenth percentile for gestational age. Neonatal examination confirmed all fetuses to be growth retarded with birth weights at or below the tenth percentile for gestational age. These findings indicate that growth of the transverse cerebellar diameter is unaffected by intrauterine growth retardation; thus this sonographic measurement may serve as an independent and reliable correlate of gestational age against which potential deviations of growth may be compared.