To propose a novel prenatal sonographic diagnostic method for fetuses with subarachnoid hemorrhage (SAH).

This was a retrospective study of five fetuses with SAH diagnosed by ultrasound and MRI at Shenzhen Maternity and Child Healthcare Hospital between 2018 and 2021, in which we systematically analyzed and summarized the prenatal ultrasound diagnostic strategy and sonographic features in fetal SAH.

The typical ultrasound manifestations of SAH were: (1) uniform hyperechoic area in the sylvian fissure (n=5); (2) enhanced echo in the surface sulci including the subfrontal sulcus, superior temporal sulcus, and parieto-occipital sulcus (n=4); (3) evenly strong echo in the supracarpal cistern, annular cistern, and interstellar cistern (n=3); (4) hyperecho in anterior and posterior longitudinal fissures, sagittal sinus, or sinus confluence (n=2); (5) subarachnoid thickening with strong echo through the sagittal plane of the spina conus (n=1); (6) hemorrhage at other parts of the brain, causing cerebral parenchymal or intraventricular hemorrhage (n=4); (7) increased blood flow velocity in the middle cerebral artery (n=4); and (8) no blood flow signal in the hemorrhage focus on CDFI.

Typical uniform hyperechoic manifestations of the sylvian fissure are an important clue for prenatal ultrasound to detect and diagnose fetal SAH. It is suggested to identify uniform hyperechoic manifestations on the brain surface including the sulci, cistern, and other parts of the brain. Such manifestations are reliable diagnostic signs to identify whether SAH is combined with other intracranial hemorrhage.