FETAL ANOMALY DETECTION BY 2ND-TRIMESTER ULTRASONOGRAPHY IN A TERTIARY CENTER

OBJECTIVE: Our purpose was to determine the relative accuracy of indic ated versus screening second-trimester ultrasonography for detection o f fetal anomalies and to assess the cost effectiveness of anomaly scre ening. STUDY DESIGN: The study population consisted of 2031 pregnant w omen with singleton gestations who prospectively underwent ultrasonogr aphic scanning between 15 and 22 weeks and received complete obstetric care at the Medical University of South Carolina between July 1, 1993 , and June 30, 1996. Patients were divided into two groups: (1) indica ted and (2) screening. The cost of screening ultrasonography was compa red with the cost of newborn care for selected anomalous fetuses. RESU LTS: Forty-seven fetuses (2.3%) were diagnosed by ultrasonography as h aving a major anomaly: 8.6% in the indicated group and 0.68% in the sc reening group (p = 0.001). The sensitivity for detecting the anomalous fetus was 75.0% overall: 89.7% in the indicated group and 47.6% in th e screening group (p = 0.001). Of the 47 patients diagnosed with fetal anomalies, 11 (23.4%) chose pregnancy termination; of the 35 (74.5%) live-born anomalous infants, 29 (82.9%) were discharged alive. Project ed newborn cost savings offset the cost of routine midtrimester screen ing. CONCLUSIONS: Detection of anomalous fetuses was significantly bet ter in the indicated compared with the screening group. Nevertheless, routine ultrasonographic screening appeared cost-effective in our popu lation.