Prenatal Ultrasound Screening to Diagnose Congenital Anomalies Among One Thousand Unselected Women and Their Pregnancy Outcome

OBJECTIVES: Purpose of our study was to determine the detection rate of congenital anomalies in second trimester by single prenatal ultrasound screening in an unselected population and to evaluate the subsequent pregnancy outcome and to compare the results with published series using standardized criteria. SUBJECTS AND METHODS-One thousand pregnant women at 18-22 weeks' gestation were screened by prenatal ultrasound examination. We compared these sonographic reports with pregnancy outcomes established by postnatal echocardiography and ultrasound examinations of neonates and autopsy for dead fetuses. Statistical analysis was performed on two units; malformed fetus and malformation itself. RESULTS-A total of 27 fetuses with 30 anomalies were identified by prenatal ultrasound. Prospectively 2 babies with 2 anomalies were found to be normal. On postnatal examination 13 babies were found to have 14 anomalies which could not be detected by ultrasound. Thus the sensitivity of ultrasound in detecting congenital anomalies and anomalous fetuses was 66.6% and 67.5% respectively. Highest detection rate was observed for CNS anomalies (88.8%) but that of craniofacial and musculoskeletal anomalies was not very satisfactory (33% in each system). CONCLUSION-This study shows rate of detection of fetal anomalies is satisfactory for most organ systems except cardiac, musculoskeletal and craniofacial malformations.