Fetal cervical hyperextension in arthrogryposis.

Perhaps the most dramatic position of a newborn after delivery is when there is hyperextension of the neck and spine. It will have been presented in utero and today, almost always, such babies will have been delivered by C-section. The associated anomalies are variable. The process(es) that can lead to cervical hyperextension is/are largely unknown. The outcome is variable from lethal to completely resolve. Individuals with arthrogryposis and in particular with Amyoplasia appear to have an increased frequency of neck, cervical, and spine hyperextension at birth. We present here 41 cases of arthrogryposis (mainly Amyoplasia) with fetal cervical hyperextension. The outlook is surprisingly good if spinal cord trauma does not occur. Ultrasound late in pregnancy when arthrogryposis is recognized prenatally should determine whether cervical hyperextension has developed, so that appropriate preventive measures can be taken.