Abstract:Objectives: To evaluate the changes in middle cerebral artery (MCA) Doppler blood flow in fetuses with congenital hydrocephalus in relationship with perinatal mortality. Methods: This a prospective study conducted in King Fahad Medical City, Riyadh, Saudi Arabia from January 2008 to December 2010. All fetuses diagnosed with congenital hydrocephalus had detailed morphology scans. The associated congenital anomalies, cortical mental thickness measurement, and MCA Doppler abnormalities ware marked. Perinatal mortality rates were evaluated in relation to those three findings. The main outcome measures were MCA Doppler changes and perinatal mortality rate. Results: We managed 116 cases of congenital ventriculomegaly and hydrocephalus (35 cases with mild ventriculomegaly, 29 cases with severe ventriculomegaly, and 52 cases with hydrocephalus). The birth incidence of congenital hydrocephalus was 3.52 per 1,000 live births and the total perinatal mortality rate was 40.4% (21/52). Out of 52 cases of hydrocephalus, 9 fetuses were diagnosed with abnormal MCA Doppler (absent or reverse diastolic flow). All nine fetuses died before the age of 24 hours. Abnormal MCA Doppler and a cortical mental thickness measurement of less than 10 mm were significantly associated with higher perinatal mortality rates with a relative risk of 4.42 and 3.58 respectively. The association of congenital hydrocephalus with other congenital anomalies was not statistically associated with higher perinatal mortality. Conclusion: Congenital Hydrocephalus is a common abnormality that is associated with high perinatal mortality. Abnormal MCA Doppler blood flow appears to be a marker of poor prognosis and high perinatal mortality.