Spectrum and Diagnostic Accuracy of 11–13 Weeks Scan in Detecting Fetal Limb Abnormalities

ABSTRACT Objectives To assess the efficacy of the 11–13 + 6 ‐week ultrasound scan in detecting fetal limb abnormalities. Methods This observational study included all women undergoing an 11–13 + 6 ‐week ultrasound scan at a single tertiary care center in India. Detection of limb abnormalities at the first‐trimester scan was compared with findings from second‐trimester anomaly scans. Final diagnoses were confirmed at delivery or by autopsy, where available. Results Among 18 031 pregnancies evaluated, 259 fetuses were diagnosed with limb abnormalities (incidence 1.44%). Of these, 148 were detected in the first trimester. Talipes ( n ‐49) was the most common abnormality identified, followed by limb reduction defects ( n ‐36), arthrogryposis ( n ‐35), and skeletal dysplasias ( n ‐28). The most frequent associated anomalies were multisystem and central nervous system abnormalities. Conclusions Our study demonstrates that the 11–13 + 6 ‐week scan is an effective screening tool for major fetal limb abnormalities. However, large prospective cohort studies in unselected, low‐risk populations, with robust postnatal or postabortal confirmation, are required to accurately determine the true efficacy of first‐trimester ultrasound in diagnosing fetal limb abnormalities.