Subdural hemorrhage (SDH) detected postnatally in the newborn infant is usually related to trauma at the time of vaginal delivery. With improvement in obstetric methods, the incidence of this problem has declined. However, with advances in obstetric ultrasonography, it has been recognized that SDH may occur in utero before the onset of delivery. Intrauterine SDH remains a rare event. A review of the literature revealed only 32 cases to date (Tables I and II). Neonatal SDH is venous in origin and associated with trauma in most cases. Etiopathogenesis of neonatal SDH is explained by shearing of bridging veins or other venous structures caused by trauma. Instrumental delivery (forceps or vacuum extraction) causes distortion of the infant's cranium with elongation of the falx and angulation of the tentorium, leading to tearing of posterior fossa venous structures and bleeding into the subdural space. Rupture or tearing of large venous channels, such as the great vein of Galen, straight or transverse sinus or falx laceration with rupture of the sagittal sinus, result in accumulation of blood in both the supratentorial and infratentorial compartments. However, etiopathogenesis of intrauterine SDH is less certain. The fetus is usually well protected from direct abdominal trauma by maternal structures and amniotic fluid. Fetal intracranial vessels may be susceptible to shearing or acceleration/deceleration forces because of the following features: first, the head is large and neck muscles weak; this allows more rotational movement with angular acceleration. Second, the subarachnoid space is larger, allowing the brain to move within the cranium easily. Third, the fetal brain has a higher water content that increases its mass and allows it to develop more momentum when acceleration is applied. These unique conditions could make the fetus more susceptible to developing subdural hematomas and allow the development of subdural hematomas without obvious trauma.