The utility of ultrasound for the detection of fetal limb abnormalities - a 20-year single-center experience

Objective: The standard obstetric ultrasound examination includes documentation of arms and legs. The purpose of this study is to review the efficacy of ultrasound for the detection of limb anomalies, the type and incidence of associated malformations and pregnancy outcomes. Method: All cases of polydactyly (POD), abnormal hand position (AHP), limb reduction defects (LRD) and arthrogryposis (ART) scanned in our Unit between 1990 and 2010 were identified. Cases were categorized as isolated (ISO) or non-isolated (NISO). The accuracy of prenatal diagnosis, type and incidence of associated malformations and aneuploidy and pregnancy outcomes were determined. Results: Most cases were NISO. The sensitivity of ultrasound was 19.1% for POD, 76.0% for AHP, 76.0% for LRD involving the long bones and 81.3% for ART. Cardiothoracic and facial defects were the most common accompanying malformations. The risk for aneuploidy ranged from 3.6% for POD to 47.2% for AHP. The live birth rate ranged from 85.5% for POD to 24.5% for AHP. Conclusion: While imaging of the arms and legs allows detection of most cases of AHP, LRD involving the limbs and ART, a probable minimum of 20% to 25% of cases will escape prenatal diagnosis. Identification of these defects should prompt an extended anatomic survey and consideration of invasive testing for aneuploidy.