The development of the fetal vermis:: an in-utero sonographic evaluation

Objective To establish a nomogram for fetal vermis measurements during gestation. Methods A prospective cross-sectional study of normal singleton pregnancies. Measurements of the fetal vermis width (in the axial plane) and height (in the sagittal plane) were performed by high-resolution transabdominal ultrasonography between 18 and 38 weeks of gestation in 256 fetuses. Results Adequate vermis measurements were obtained in 256 fetuses. Vermian width and height as a function of gestational age and biparietal diameter were expressed by regression equations and the correlation coefficients were found to be highly statistically significant (P < 0.0001). The normal mean (+/- SD) for each gestational week was defined. Conclusions The present data offer the normal range of the vermian measurements throughout gestation, These values may allow intrauterine assessment of the development of the cerebellar vermis, as well as the posterior fossa.