The fetal superior cerebellar vermian width in normal, growth-restricted and macrosomic fetuses

To obtain dimensions of the fetal superior cerebellar vermian width as a basis for further studies and for comparisons with deviation in growth.

The study group included 266 normal pregnant women from 20 to 37 weeks of gestation. Several biometric measurements were obtained throughout pregnancy, including the fetal superior cerebellar vermian width. Forty-three growth-restricted and 30 macrosomic fetuses were included in this study.

A linear growth function was observed between the superior cerebellar vermian width and gestational age (GA) (R = 0.859; p < 0.00001; y = -4.033 + 0.416 x GA), transverse cerebellar diameter (TCD) (R = 0.870; p < 0.00001; y = 0.404 + 0.223 x TCD), biparietal diameter (BPD) (R = 0.823; p < 0.00001; y = -3.086 + 0.155 x BPD), head circumference (HC) (R = 0.82; p < 0.00001; y = -3.21 + 0.434 x HC), femoral length (FL) (R = 0.843; p < 0.00001; y = -1.75 + 0.184 x FL) and humeral length (HL) (R = 0.824; p < 0.00001; y = -2.691 + 0.223 x HL). The ratio between the superior cerebellar vermian width and the transverse cerebellar diameter remained constant throughout gestation. In all 43 growth-restricted and the 30 macrosomic fetuses, the dimensions of the fetal superior cerebellar vermian width remained within the normal range for the indexed gestational age.

These results provide normative data for the fetal superior cerebellar vermian width in various dimensions and across gestational ages. In addition, growth of the superior cerebellar vermis remained normal in growth-restricted as well as macrosomic fetuses. Therefore, cerebellar vermian growth may be used adjunctively as a standard against which deviant fetal growth may be compared when precise gestational age determination is necessary.