Prenatal detection of upper limb differences with obstetric ultrasound

Purpose To determine the sensitivity, specificity, and predictive values of prenatal ultrasound detection of fetal upper extremity anomalies at a single tertiary care center in a large patient cohort. Our secondary purpose was to assess factors affecting prenatal detection including the presence of associated anomalies. Methods We performed a retrospective review of prenatal ultrasound and postnatal clinical records from each pregnancy evaluated with a prenatal ultrasound at the Washington University Department of Obstetrics and Gynecology over a 20-year period. We searched for upper extremity anomaly diagnosis codes pre- and postnatally and correlated with clinical postnatal follow-up to determine prevalence, sensitivity, specificity, predictive values, and associated conditions. Results A total of 100,856 pregnancies were evaluated by prenatal ultrasound, which included 843 fetuses diagnosed with a musculoskeletal anomaly (prevalence, 1 of 120) and 642 with an upper extremity anomaly (prevalence, 1 of 157). The postnatally confirmed sensitivity for prenatal ultrasound detection of an upper extremity anomaly was 42%. Sensitivity was lower in cases isolated to the upper extremity (25% vs 55%). Sensitivity was highest for conditions affecting the entire upper extremity (70%-100%) and lowest for those affecting the digits alone (4%-19%). Fetuses with limb reduction defects, radial longitudinal deficiency, phocomelia, arthrogryposis, abnormal hand positioning, and cleft hand had a higher likelihood of having an associated anomaly. Conclusions At our tertiary referral center, there was a notable prevalence of upper extremity anomalies; however, the overall sensitivity for detecting them with prenatal ultrasound was low. This was disappointing given the value of prenatal identification of anomalies for parental counseling. Prenatal diagnosis of anomalies affecting the entire upper limb was more reliable than diagnosis of more distal anomalies. Type of study/level of evidence Diagnostic III.