Ultrasonic studies of human fetal brain development

Abstract The area of functional human fetal brain development is largely terra incognita for obvious technical reasons. There have been several elegant fetal anatomical studies, but these have been simple point samplings of necropsy material with a potential bias on studies of fetal or maternal—fetal conditions associated with early delivery. A large number of neuro-developmental observations have been accumulated for exteriorized fetal animals (chiefly the sheep) but it is not clear that these can be extrapolated to human development either temporally or organizationally. Finally, vast clinical progress in neonatology has enabled sequential observations of premature infants, beginning at the start of the third trimester. However, intensive-care nursery conditions are quite different from those of the intact intrauterine environment, and because of the clinical fragility of these infants and the circumstances resulting in their premature delivery, asphyxial brain injury or intracranial hemorrhage may complicate the analysis and interpretation of those data. Ultrasound imaging has provided a means of making non-invasive sequential fetal observations. This capability has been extended by technical advances that have occurred within the past two years, providing some new possibilities for monitoring CNS development.