Abnormal biochemical serum screening versus 2nd-trimester ultrasound-detected minor anomalies as predictors of aneuploidy in low-risk patients

Abstract

Objective: To compare the yield of multiple-marker biochemical screening with that of minor fetal anomalies observed on ultrasound for detection of aneuploidy in low-risk patients.

Methods: The results of 1,073 amniocenteses performed because of abnormal biochemical screening tests were compared against 197 amniocenteses performed for minor anomalies as detected on level II ultrasound at 15-22 weeks of gestation.

Results: False-positive results were observed in about 7% of serum screening patients and in 1.7% of the ultrasound cases. Chromosomally abnormal fetuses were detected in 2% of the amniocenteses performed because of abnormal serum screening and in 2.5% of the cases with ultrasound-defined minor anomalies.

Conclusions: Both methods identify patients at risk for abnormal karyotypes. Although the evaluation of serum biochemical markers yielded more false-positive results, it is more suitable than ultrasound for mass population screening.