Ultrasonographic diagnosis of congenital anomalies in twins

To determine whether serial ultrasonographic examinations with basic anatomic surveys provide an adequate screen for congenital abnormalities that are more common in twins, we compared the results of prenatal sonograms and neonatal examinations for 314 twins (157 pairs) delivered during a recent 42-month period. An anomaly was defined as major if it potentially required surgical repair or precluded normal life expectancy; otherwise it was defined as minor. Thirty-three twins (9.5%) had 40 anomalies; 28 (9%) were major and 12 (4%) were minor. Prenatal ultrasonography with cardiac screening limited to the four-chamber view provided detection of 39% of all major anomalies, 55% of noncardiac major anomalies but none of the cardiac lesions, and 69% of the major anomalies for which routine prenatal management should be altered. No false-positive diagnoses incorrectly altered management. We conclude that serial prenatal ultrasonographic examinations are useful in detecting noncardiac anomalies for which twins are at increased risk, but the four-chamber view is not an adequate screen for the cardiac malformations of twins.