Characteristics of persistent occiput posterior position

Persistent occiput posterior position is primarily characterized by abnormal fetal head positioning during labor. The fetal head engages in the pelvis in an occiput posterior or occiput transverse position, but during descent, due to certain factors such as poor flexion of the fetal head or abnormal pelvic morphology, the occiput fails to rotate forward and remains persistently located toward the maternal pelvis's posterior or lateral side. This leads to difficult labor, often manifesting as prolonged or arrested second stage of labor. Because the occiput continuously presses against the posterior pelvis and compresses the rectum, the mother may experience premature rectal pressure and urge to defecate, leading to early bearing down efforts. This can easily result in edema of the anterior cervical lip and maternal exhaustion, further impeding labor progression. On abdominal examination, the clinician may observe that the fetal back is deviated toward the maternal posterior or lateral aspect, and the fetal heart sounds may be correspondingly displaced.