The authors examined the brains of two infants in whom episodes of fetal compromise could be accurately correlated with gestational age. A mother who had sustained hypotensive shock at 16 weeks gestation gave birth at 20 weeks to a stillborn infant whose brain showed cystic necrosis of the lenticular nuclei and multifocal polymicrogyria. The brain of a seven-month-old infant born at 33 weeks gestation to a mother who had experienced respiratory arrest during her 28th week showed thalamic and brainstem necrosis accompanied by diffuse white matter gliosis. Review of the literature yielded 10 similar cases. When the insults occurred before 24 weeks of gestation, bilateral pallidal necrosis was a constant feature. Between 26 and 34 weeks, the common finding was thalamic necrosis, often accompanied by brainstem necrosis. These observations should be of assistance in determining the timing of gestational insults, and therefore possible clinical correlations, in prenatal brain damage.