Ultrasonographic evidence of persistent hyperextension of the fetal neck: is it a true sign? A diagnostic and prognostic challenge

Objective: The purpose of this study was to evaluate the clinical evolution, structural anomalies associated and neonatal outcomes of fetal neck hyperextension in two cases with prenatal ultrasound diagnosis in two different gestational ages. Methods: In 2019, two cases of fetal hyperextension came to our attention. Follow-up information was obtained from hospital medical records and obstetrical care providers. Results: Two woman were investigated in our institution for the presence of fetal abnormalities in the II and III trimester, respectively. In both cases, fetal attitude presented persistent fetal neck hyperextension. One of the two fetuses had a mild ventriculomegaly and suspected for micrognathia. Both had an amniotic fluid increase. One of two had no movement in the lower and upper limbs in ultrasound scans associated with club foot and suspected scoliosis. Both were born by cesarean section with pretty different prognosis: one healthy baby had a retarded psychomotor development and the other one died after 6 months. A precise diagnosis was possible only in one case. Conclusion: The early identification of a fetus with persistent hyperextension of the fetal head should require a detailed ultrasound exam for structural abnormalities and a careful prenatal counseling due to possible postnatal outcome.