Persistent Fetal Neck Hyperextension in Early Gestation

Hyperextension of the fetal neck is an uncommon but clinically significant finding with diverse etiologies ranging from isolated postural variations to lethal congenital anomalies. Potential associated conditions include anencephaly, iniencephaly, cervical spine malformations, and syndromic musculoskeletal disorders. Advances in prenatal imaging have improved recognition, yet diagnostic challenges and management dilemmas persist. In this review, we synthesize current evidence on the embryology, pathogenesis, diagnosis, differential diagnosis, clinical implications, and management strategies of fetal hyperextended neck. Further studies are needed to refine diagnostic cut-offs, explore the natural course of the condition over time, and establish consensus protocols for clinical practice.