Pugash D et al. – The fetal subplate and intermediate zones can be reliably demonstrated on routine sonography before 28 weeks, and disappear after 34 weeks. These findings represent normal gestational age–dependent transient laminar patterns of cerebral development and are consistent with histological studies. Changes in the sonographic visualization of lamination are related to composition of the subplate zone due to development of fibre systems and axon strata in the developing white matter. Sonography is therefore able to identify evidence of cortical lamination in the normal fetal brain, and assess timing of maturation changes. Abnormal fetal cerebral lamination patterns for gestational age are also visible on sonography, and may indicate abnormal brain development.