Cerebellar measurements with ultrasonography in the evaluation of fetal growth and development.

A prospective study of ultrasonography was conducted in 371 normal pregnant women, with gestational ages ranging from 13 weeks to 40 weeks. Several biometric measurements were obtained including the transverse cerebellar diameter, the biparietal diameter, the occipitofrontal diameter, and the calculated head circumference. Curvilinear relationships were found between the transverse diameter of the cerebellum (measured in millimeters), and the gestational age (R2 = 0.948; P = 0.001), the biparietal diameter (R2 = 0.956; P = 0.0001), and the head circumference (R2 = 0.969; P = 0.0001). A nomogram of cerebellar measurements estimating gestational age and predicting the biparietal diameter and head circumference was generated. Throughout pregnancy the establishment of normative cerebellar measurements allows for the estimation of gestational age that is independent of the shape of the fetal head and offers potential for evaluation of abnormal fetal growth and anomalous development of the central nervous system.