Use of the transverse cerebellar diameter/abdominal circumference ratio in pregnancies at risk for intrauterine growth retardation.

A prospective study was conducted to evaluate the ability of the transverse cerebellar diameter/abdominal circumference ratio to identify growth-retarded fetuses. Of the cases analyzed, 48 of 87 (55%) were growth retarded by birth weight. The transverse cerebellar diameter/abdominal circumference ratio identified growth retardation with a sensitivity of 71%, specificity of 77%, positive predictive value of 79%, and negative predictive value of 68%. Fourteen growth-retarded fetuses were missed by the ratio; however, 57% of the missed cases were severely growth retarded. The transverse cerebellar diameter/abdominal circumference ratio can be useful for the assessment of fetal growth retardation; however, the ratio may be normal in cases of severe fetal growth retardation.