Detection of congenital anomalies before or after birth; does it make a difference?

Ultrasound has made it possible to detect structural anomalies in the fetus. In the Netherlands universal population based screening for congenital anomalies was only introduced at the beginning of 2006, which was the reason why prior to this period many congenital anomalies were detected either late in pregnancy or sometimes only at birth. This situation set the scene to investigate whether the outcome of minor and major anomalies was altered by a prenatal detection versus a detection at birth. We investigated the outcome of six major and one minor anomaly. We defined the anomalies as isolated or associated, if either other anomalies or an abnormal karyotype were also present. Prenatal detected spina bifida, associated omphalocele and associated clubfoot revealed a high percentage of terminated pregnancies, intrauterine and neonatal death and survival varied between 14 and 28%. When these anomalies were detected at birth the survival varied between 81 and 100%. Outcome for liveborn infants with a pre- or postnatally diagnosed isolated duodenal obstruction (DO) or gastroschisis was not essentially different despite more prematurity in the prenatal DO group. Adapting prenatal management for gastroschisis may reduce the 10% intrauterine death rate. The morbidity for prenatally detected isolated clubfoot and multicystic dysplastic kidney was reduced due to early confirmation and treatment in a specialized center. Prenatal selection of cases with mild renal pyelectasis at risk of pathology reduced morbidity. In conclusion, depending on the anomaly a prenatal diagnosis may increase or reduce mortality. For a number of anomalies the morbidity will be reduced.