Diagnosis of fetal limb abnormalities before 15 weeks: cause for concern

The purposes of this study were (1) to identify cases of limb abnormalities identified before 15 weeks and correlate with outcomes and (2) to assess first-trimester nuchal translucency examinations to determine how frequently the upper and lower limbs were identified.

A retrospective review was conducted of sonographic studies up to 15 weeks' gestational age from 2003 to 2010 at our high-risk fetal center. Data were collected regarding fetal gestational age, limb abnormalities, associated anatomic abnormalities, pregnancy outcomes, karyotypes, autopsy results, and the utility of transabdominal sonography, transvaginal sonography, and 3-dimensional sonography. A retrospective analysis of 100 consecutive first-trimester examinations was also conducted to assess the sensitivity of transabdominal sonography in visualization of limb buds.

A total of 15 cases were identified with a mean gestational age of 12 weeks 6 days. Club hand was the most common abnormality seen (8 cases), followed by absence of long bones (5 cases), a missing limb (5 cases), club foot (5 cases), shortening of long bones (2 cases), abnormal hands (2 cases), clenched hands (2 cases), and overlapping digits (1 case). Trisomy 18 was present in 9 cases. Transabdominal sonography allowed for detection of all limb buds in 100 consecutive nuchal translucency examinations and 9 of 15 cases of limb abnormalities. Four of the cases resulted in fetal death, and the remaining 11 cases were terminated.

Fetal limb abnormalities can be detected on sonography before 15 weeks' gestational age and are often associated with serious congenital conditions, especially trisomy 18. Transabdominal sonography alone can show most of these abnormalities, although transvaginal and 3-dimensional sonography can provide additional information. Targeted evaluation of fetal limbs during sonography before 15 weeks should be considered in high-risk populations.