occipitoposterior

Occipitoposterior refers to the orientation of the fetal head during labor in which the occipital bone is directed toward the mother’s posterior pelvis. When the occiput faces posteriorly, the fetus is described as in an occipitoposterior (OP) position, with subtypes left OP or right OP depending on which side of the pelvis the occiput is facing.

In many pregnancies, the fetus begins labor in an OP position or shifts between positions. A substantial number rotate to occipitoanterior (OA) during labor, and many OP presentations result in vaginal delivery without complications. Persistent OP at delivery or labor arrest is less common and is associated with longer labor, increased back pain during labor, and higher rates of operative vaginal delivery or cesarean section, though outcomes can still be favorable with appropriate management.

Diagnosis is typically clinical, based on palpation of the fetal head during labor or a vaginal examination, which may reveal a posteriorly facing occipital pole and a posterior fontanelle position. Ultrasound can confirm the orientation of the fetal head when needed.

Management focuses on promoting rotation and a safe delivery. Many cases resolve spontaneously with position changes and activity, such as upright or forward-leaning positions and, in some circumstances, hands-and-knees positioning. Manual rotation by a clinician may be attempted, particularly if labor is not progressing. If labor cannot progress or fetal well-being is compromised, operative delivery with forceps or vacuum extraction or cesarean delivery may be indicated, guided by maternal and fetal status, gestational age, and clinical context.

Prognosis is generally favorable, with most OP presentations delivering vaginally, often after rotation to OA during labor.