Persistent Occiput Posterior

Persistent occiput posterior (OP) position, when the fetal occiput stays in the posterior of the maternal pelvis until the time of delivery, has an incidence of 5% to 12%. Persistent OP can be influenced by epidural analgesia, parity, race, and shape of the pelvis. When discovered in the active or early second stages of labor, OP often resolves without effort. When it does not spontaneously resolve, persistent OP and complications may be reduced by prophylactic manual rotation. Other methods for resolution include nonrotational operative vaginal delivery, the use of rotational forceps, or, increasingly, cesarean delivery. This article is a comprehensive review of the outcomes and management of the persistent OP fetus. Studies have demonstrated that OP is associated with longer first and second stages of labor, the need for labor augmentation, and higher rates of cesarean delivery, operative vaginal delivery, failed operative vaginal delivery, and third- and fourth-degree perineal lacerations. During intrapartum care, OP is associated with a higher rate of abnormal fetal heart patterns. Occiput posterior newborns have been found to have higher rates of low Apgar scores (odds ratio [OR], 1.5; 95% confidence interval [CI], 1.17-1.91), meconium (OR, 1.29; 95% CI, 1.17-1.42), birth trauma (OR, 1.77; 95% CI, 1.22-2.57), cord gas acidemia (OR, 2.05; 95% CI, 1.52-2.77), and neonatal intensive care unit admission (OR, 1.57; 95% CI, 1.28-1.92). While diagnosis is typically made using physical examination, this is often inaccurate prior to full cervix dilation. Ultrasonography can also be used for diagnosis and can be more accurate during the second stage of labor than digital vaginal examinations. The author of the review believes ultrasonography is not necessary before all operative vaginal deliveries. The author does recommend the following guidelines when consulting on a persistent OP before the onset of labor, as no prelabor interventions are effective in reduction of persistent OP. During the first stage of labor, maternal positioning to encourage rotation of the occiput has not been supported by evidence. In the early second stage, there is no need for intervention for OP if labor is progressing, but if OP continues later into the second stage, when the likelihood of spontaneous rotation decreases, and adverse outcomes become more likely, the options at that point to facilitate rotation are forceps rotation or manual rotation. The decreasing number of clinicians who will perform or teach rotations with Kielland forceps presents a challenge. While not all residents should be trained for proficiency in procedures such as this, those who are trained in Kielland forceps should be willing to perform and teach the procedure. Manual rotation may be easier to teach and have a wider acceptance by clinicians and patients alike. In a prospective study, Reichman and colleagues found deliveries that underwent prophylactic rotation halfway into the second stage were more likely to be occiput anterior at delivery compared with an expectant management group (93% compared with 15%, P < 0.001) and more likely to deliver vaginally. In summary, persistent OP appears to contribute to the particularly high cesarean delivery rate and deserves attention by obstetric clinicians.