asynclitism
Pronunciation: ay-SIN-kli-tizm
Lateral deflection of the fetal head during descent through the birth canal, where the sagittal suture is not aligned centrally in the pelvis.
Full Definition
Asynclitism refers to the lateral tilting or deflection of the fetal head as it descends through the birth canal, resulting in non-alignment of the sagittal suture with the anteroposterior diameter of the maternal pelvis. Anterior asynclitism (Naegele's obliquity) occurs when the anterior parietal bone presents first, while posterior asynclitism (Litzmann's obliquity) involves presentation of the posterior parietal bone. Mild asynclitism is physiological and aids in accommodation to pelvic dimensions, but severe asynclitism can impede normal descent and rotation, potentially leading to prolonged labor, operative delivery, or cesarean section. Recognition is important for appropriate management of labor dystocia.
Usage
Usage note: Technical term requiring understanding of fetal positioning; distinguish from general malposition.
In Context
- "Significant asynclitism was noted on vaginal examination, explaining the lack of descent in the second stage." — Labor progress assessment
- "Posterior asynclitism contributed to failure to progress requiring operative delivery." — Assisted delivery indication