TITLE:
Fetal Head Compression: Its Possible Role in Neurologic Injury
AUTHORS:
Barry S. Schifrin, Brian J. Koos, Wayne R. Cohen
KEYWORDS:
Fetal Brain Injury, Fetal Head Compression, Ischemic Encephalopathy, Neonatal Encephalopathy
JOURNAL NAME:
Open Journal of Obstetrics and Gynecology,
Vol.14 No.1,
January
31,
2024
ABSTRACT: It is widely assumed that
fetal ischemic brain injury during labor derives almost exclusively from severe,
systemic hypoxemia with marked neonatal depression and acidemia. Severe asphyxia,
however, is one of several causes of perinatal neurological injury and may not
be the most common; most neonates diagnosed
with hypoxic-ischemic encephalopathy do not have evidence of severe asphyxia. Sepsis,
direct brain trauma, and drug or toxin exposure account for some cases, while
mechanical forces of labor and delivery that increase fetal intracranial
pressure sufficiently to impair brain perfusion may also contribute. Because of
bony compliance and mobile suture lines, the fetal skull changes shape and
redistributes cerebrospinal fluid during labor according to constraints imposed
by contractions, and bony and soft tissue elements of the
birth canal as the head descends. These accommodations, including the increase in intracranial pressure, are adaptive and necessary for efficient
descent of the head while safeguarding cerebral blood flow. Autonomic reflexes
mediated through central receptors normally provide ample protection of the
brain from the considerable pressure exerted on the skull. On occasion, those
forces, which are transmitted intracranially, may overcome the various adaptive
anatomical, cardiovascular, metabolic, and neurological mechanisms that
maintain cerebral perfusion and oxygen availability, resulting in ischemic
brain injury. Accepting the notion of a potentially adverse impact of fetal
head compression suggests that avoidance of excessive uterine activity and of
relentless pushing without steady progress in descent may offer protection for
the fetal brain during parturition. Excessive head compression should be
considered in the differential diagnosis of ischemic encephalopathy.