TRANSVERSE CEREBELLAR DIAMETER AND TRANSVERSE CEREBELLAR DIAMETER ABDOMINAL CIRCUMFERENCE INDEX FOR ASSESSING FETAL GROWTH

In a prospective study of 330 pregnant women, measurements of the tran sverse cerebellar diameter (TCD), abdominal circumference (AC), bipari etal diameter (BPD), head circumference (HC) and TCD/AC ratio and HC/A C ratio were obtained using conventional ultrasonography between 16th and 41st weeks of gestation. Measurement of BPD yielded a strong corre lation with gestational age (r = 0.9880 and R(2) = 0.9761) by cubic re gression analysis. The measurement of TCD also had a very close relati on with gestational age (r = 0.9767 and R(2) = 0.9539). The ratio betw een TCD and AC was calculated and found to be 0.1436 +/- 0.0106 (SD) w hich remained fairly constant throughout pregnancy, while the BPD/AC r atio declined. The 5th and 95th percentiles for this ratio were 0.1279 and 0.1603. Ten of eleven fetuses with TCD/AC ratios exceeding 2 SD ( 0.1648) were found to have asymmetrical intrauterine growth retardatio n upon neonatal examination. It is demonstrated that both BPD and TCD measurements are reliable techniques that correlate well with gestatio nal age, and the TCD/AC ratio is valuable in identifying babies with a symmetrical intrauterine growth retardation.