First-Trimester Diagnosis of Supernumerary Hemivertebra.

Hemivertebra is a common cause of congenital scoliosis and results from a lack of formation of one-half of the vertebral body. This condition is very rare and can present as solitary or as a syndrome component: i.e., the split notochord syndrome, which often implies vertebral defects, from a bifid vertebra to hemivertebrae, or fused vertebrae. We describe a case of supernumerary lateral hemivertebra detected prenatally at 12 weeks of gestation and the ultrasonography specifics that lead to early and accurate diagnosis, monitoring during pregnancy, and follow-up at the 4-year period. The case is presented to specify the importance of an early assessment of fetal spine and diagnosis of various conditions, including hemivertebrae, considering the significant association with other anomalies (cardiovascular, urinary, skeletal, gastrointestinal, and central nervous systems), which are most commonly involved. Moreover, the need to counsel future parents on the risks implied by this anomaly is important for the obstetrician. We underline the inclusion of these types of congenital conditions in high-risk pregnancy because of the frequent association with high cesarean delivery rates, growth restriction, delivery before term, and higher morbidity rates.