How is labor affected when the fetus is in an occiput posterior op position?

Occiput posterior (OP) positions account for 15 to 20% of cephalic presentations at the onset of labor [1], [2], [3], [4]. Although spontaneous rotation in occiput anterior (OA) position occurs in most cases, the OP position persists at delivery in nearly 10% and is associated with obstetric complications, including prolonged labor, cesarean delivery, operative vaginal delivery, third- and fourth-degree perineal tears or lacerations, postpartum hemorrhage (PPH) and chorioamnionitis [5], [6], [7], [8], [9], [10], [11], [12]. The causation of posterior positions is multifactorial and observational studies report the following risk factors for their persistence at delivery: nulliparity, obesity, high maternal age, maternal sub-Saharan African origin, prolonged pregnancy, macrosomia, anterior placenta and epidural analgesia [1], [5], [13], [14], [15].

Nonetheless, the effectiveness of obstetric management strategies promoting the rotation of posterior positions, especially during the first stage of labor, remains to be demonstrated. Manual rotation is an effective method for turning the fetal head [16], but it is successful more often during the second stage of labor [17] and can sometimes cause fetal heart rate abnormalities, cervicovaginal injuries and in rare cases cord prolapse [18]. Another strategy uses maternal postures, such as hands-and-knees, lateral decubitus adapted to fetal station or lateral asymmetric decubitus. These are less iatrogenic and may promote earlier rotation, but randomized trials have not provided evidence of their effectiveness in promoting rotation of OP positions [19], [20], [21], [22]. Finally, other medical practices, such as analgesia, artificial rupture of membranes, or oxytocin infusion, are common during the first stage of labor, but studies that assess their effects on OP positions are lacking.

A better understanding of the factors affecting rotation of OP positions during the first stage of labor may help to promote earlier rotation and reduce obstetric complications associated with persistent OP positions. Accordingly, our principal objective was to identify maternal, neonatal and obstetric factors associated with rotation from OP to OA position during the first stage of labor. The secondary objective was to compare obstetric and neonatal outcomes associated with anterior rotation during this stage.

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• Fetal malposition in labour and health outcomes for women and their newborn infants: A retrospective cohort study

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• Maternal postures for fetal malposition in labour for improving the health of mothers and their infants

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• Management of persistent occiput posterior position: The added value of manual rotation

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• Simple Models to Predict Vaginal Delivery and Spontaneous Fetal Occiput Rotation Based on Intrapartum Ultrasound and Maternal Characteristics

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• The Pathophysiology of Labor Dystocia: Theme with Variations

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  To determine whether ultrasound-assessed occiput posterior (OP) position during labor can predict OP position at delivery.

  We performed a systematic literature search in PubMed, EMBASE and the Cochrane Library from inception to February 2019. Included studies needed to report both the fetal head position in labor, as assessed by ultrasound, and the corresponding actual occiput position at delivery. We used a bivariate mixed-effects model to synthesis data. We also calculated I² to test heterogeneity and explored the source of heterogeneity by meta-regression and subgroup analysis.

  Sixteen primary articles were included in this meta-analysis. Overall sensitivity and specificity of intrapartum ultrasound for prediction of persistent OP position were 0.85 (95%CI: 0.67 to 0.94) and 0.83 (95%CI: 0.77 to 0.87), respectively. The area under the receiver operating characteristic curve was 0.89 (95%CI: 0.86 to 0.91). Substantial heterogeneity was detected (I² = 98, 95%CI: 97–99), and the labor stage at ultrasound examination may be the source of heterogeneity (P = 0.00). After the stratification by extent of cervical dilatation, the predictive sensitivity and specificity at cervical dilatation ≥4 cm reached 0.92 (95%CI: 0.85 to 0.99) and 0.85 (95%CI: 0.80 to 0.91), respectively.

  Intrapartum ultrasound is a helpful tool for predicting persistent OP position, but the results of the test, especially the ultrasound examination before or at the beginning of labor, must be interpreted with caution. Re-evaluation at late labor is usually necessary.

  How is labor affected when the fetus is in an occiput posterior position?

  The posterior position at birth is associated with a higher risk of short-term complications for the baby, such as lower five-minute Apgar scores, a greater likelihood of needing to be admitted to the neonatal intensive care unit (NICU), and a longer hospital stay.

  How does occiput posterior affect labor?

  Occiput posterior (OP) position is the most common fetal malposition. It is important because it is associated with labor abnormalities that may lead to adverse maternal and neonatal consequences, particularly operative vaginal or cesarean birth.

  Does posterior position delay labor?

  Some posterior babies are born in less than 8 hours and position did not slow down labor. Some posterior babies are born in less than 24 hours and position did not slow down labor enough to be out of the norm. Some posterior babies are born in less than 36-48 hours without the need for interventions.

  What increases the risk of persistent occiput posterior position?

  Conclusion: Epidural use, AROM, African-American ethnicity, nulliparity, and birth weight >4000 g are associated with persistent OP position at delivery, with higher rates of operative deliveries and obstetric complications.