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

To assess the efficacy of the 11-13 ^+ 6-week ultrasound scan in detecting fetal limb abnormalities.

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.

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.

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.