The Prognostic significance of hyperextension of the fetal head detected antenatally with ultrasound

Abstract

Although resolution of isolated hyperextension of the fetal head is associated with a normal neonatal outcome, persistent isolated hyperextension of the fetal head can be associated with either a normal or an abnormal neonatal outcome. Fetuses with hyperextended heads and antenatally diagnosed structural anomalies have dismal outcomes. The identification of a fetus with hyperextension of the fetal head should prompt a detailed search for structural abnormalities.

Prenatal Diagnosis of Benign Extreme Hyperlordosis

“…6 Although reports on fetal hyperlordosis are very rare, several reports and case series exist about hyperextension of the fetal head. [7][8][9] Similar to hyperlordosis, it may be isolated, especially in a breech presentation, in which it has a good prognosis, but it carries a poorer outlook when associated with other anomalies. 7 In conclusion, the diagnosis of isolated fetal hyperlordosis can be made by prenatal sonography, showing a lumbar spine in extreme hyperextension.…”

“…[7][8][9] Similar to hyperlordosis, it may be isolated, especially in a breech presentation, in which it has a good prognosis, but it carries a poorer outlook when associated with other anomalies. 7 In conclusion, the diagnosis of isolated fetal hyperlordosis can be made by prenatal sonography, showing a lumbar spine in extreme hyperextension. In such cases, structural abnormalities of the spine and remaining central nervous system as well as arthrogryposis should be excluded.…”

Persistent Extreme Hyperextension of the Fetal Neck: Clinical and Neuroimaging Findings

“…Hyperextension of the fetal craniocervical junction and fetal neck is readily diagnosed by prenatal ultrasound (US) imaging. Some reports indicate that underlying structural abnormalities exist in up to one‐third of cases of hyperextension of the fetal neck . Previous studies have noted that prenatal US fails to identify such abnormalities .…”

“…Some reports indicate that underlying structural abnormalities exist in up to one‐third of cases of hyperextension of the fetal neck . Previous studies have noted that prenatal US fails to identify such abnormalities . Historically, when fetal neck hyperextension was observed in association with breech presentation (“star‐gazing position”), Caesarean, rather than vaginal, delivery was preferred in order to minimize the risk of cervical spinal cord injury …”

Three-Dimensional Sonography of Fetal Iniencephaly

“…The prenatal diagnosis is usually straightforward due to the severe distortion of the axial anatomy, the characteristic fetal position, and the grossly abnormal spine 4 – 6 . However, conditions associated with persistent hyperextension of the fetal head, such as thoracopagus conjoined twins, fetal neck masses, congenital torticollis secondary to uterine malformations or leiomyomata, congenital neuromuscular disorders, and tight nuchal cords, should be considered in the differential diagnosis 7 …”