asynclitism
Pronunciation: ay-SIN-kli-tizm
Lateral deflection of the fetal head during descent through the birth canal, where the sagittal suture deviates from the midline of the pelvis.
Full Definition
Asynclitism refers to the lateral tilting or deflection of the fetal head as it descends through the birth canal, causing the sagittal suture to be positioned off-center from the midline of the maternal pelvis. This may be anterior asynclitism (Naegele obliquity) where the anterior parietal bone leads, or posterior asynclitism (Litzmann obliquity) where the posterior parietal bone presents first. While mild asynclitism is common and may resolve spontaneously, severe asynclitism can impede labor progress and may require operative intervention. Proper recognition and documentation is important for labor management.
Usage
Usage note: Distinguish from synclitism (normal alignment). May be qualified as anterior or posterior.
In Context
- "Posterior asynclitism was noted on vaginal examination, explaining the prolonged second stage." — Labor assessment
- "The asynclitism resolved with position changes and continued descent was observed." — Delivery progress note