BACKGROUND AND OBJECTIVESThe exact antenatal prevalence of congenital anomalies in Saudi society is unknown. Early antenatal diagnosis of congenital anomalies is crucial for early counselling, intervention and possible fetal therapy. The objective of this study was to evaluate the antenatal frequency of major congenital anomalies and malformation patterns in our hospital population and to evaluate the outcome and perinatal mortality rates for major congenital anomalies.PATIENTS AND METHODSThis was a prospective study of the antenatal diagnosis of major fetal congenital anomalies conducted in the Ultrasound Department of the Women’s Specialized Hospital at King Fahad Medical City from March 2005 to February 2007. During this period, 16 639 obstetrical ultrasound examinations were performed for 7762 patients and 5379 babies delivered in our institution.RESULTSWe diagnosed 217 cases of fetal anomalies. The antenatal prevalence of congenital anomalies was 27.96 per 1000. The median maternal age at diagnosis was 27.5 years. The median gestational age at diagnosis was 31 weeks. Genitourinary and cranial anomalies were the commonest; for 186 patients delivered in our institution, the birth prevalence was 34.57 per 1000 births. The median gestational age at delivery was 38 weeks. The perinatal mortality rate was 34.9% (65/186), including all cases of intrauterine fetal and neonatal deaths.CONCLUSIONThe prevalence of major congenital anomalies in our population appears to be similar to international figures. Major congenital anomalies are a major cause of perinatal mortality.