The value of intrapartum ultrasound in the prediction of persistent occiput posterior position: Systematic review and meta-analysis

Persistent occiput posterior position: predictive factors of spontaneous rotation of the fetal head

OBJECTIVES

To assess factors associated with spontaneous rotation in the occiput anterior position for fetuses in persistent occiput posterior (OP) during the second stage of labor. To evaluate maternal and fetal outcomes after spontaneous rotation of persistent OP.

METHODS

This is a prospective cohort of 495 women with fetuses in persistent OP position, confirmed with ultrasonography during the second stage of labor. We performed simple logistic regressions, followed by multiple logistic regressions.

RESULTS

Among 495 women with fetuses in persistent OP position, 78 fetuses (16%) underwent a spontaneous rotation during the second stage of labor. The multivariate analysis found that a short duration of the first stage of labor (<7 h) was associated with a spontaneous rotation of the fetal head in the second stage of labor (OR 0.43 [0.23; 0.76. There were fewer episiotomies (25.6% vs 52.3%, p < .01), cesarean sections (0% v. 5.4%, p = .03), and instrumental deliveries (8.9% vs. 50%, p < .01) in the "spontaneous rotation" group, and the two groups were similar regarding post-partum hemorrhage.The newborns in the "spontaneous rotation" group had a higher Apgar score at 1 min (10 v. 9, p = .02). The two groups did not differ for other neonatal parameters, such as arterial pH value, Apgar score at 5 min, birth trauma, or transfer into the pediatric unit.

CONCLUSION

A shorter duration of the first stage of labor (< 7 h) is a predictive factor of spontaneous rotation in the occiput anterior position for fetuses in persistent OP position. A spontaneous rotation in case of an OP position is associated with better maternal and fetal outcomes.

The correlation between levator ani co-activation and fetal head regression on maternal pushing at term

OBJECTIVE

To assess the correlation between fetal head regression and levator ani muscle (LAM) co-activation under Valsalva maneuver.

STUDY DESIGN

This study was a secondary analysis of a prospective cohort study on the association between the angle of progression (AoP) and labor outcome. We scanned a group of nulliparous women at term before the onset of labor at rest and under maximum Valsalva maneuver. In addition to the previously calculated AoP, in the present study, we measured the anteroposterior diameter of LAM hiatus (APD) on each ultrasound image. LAM co-activation was defined as APD at Valsalva less than that at rest, whereas fetal head regression was defined as AoP at Valsalva less than that at rest. We calculated the correlation between the two phenomena. Finally, we examined various labor outcomes according to the presence, absence, or co-existence of these two phenomena.

RESULTS

We included 469 women. A total of 129 (27.5%) women presented LAM co-activation while 50 (10.7%) showed head regression. Only 15 (3.2%) women showed simultaneous head regression and LAM co-activation. Women with coexisting LAM co-activation and head regression had the narrowest AoP at Valsalva in comparison with other study groups (p < .001). In addition, they had the highest risk of Cesarean delivery (40%) and longest first, second, and active second stage durations, although none of these reached statistical significance.

CONCLUSION

In nulliparous women at term before the onset of labor fetal head regression and LAM co-activation at Valsalva are two distinct phenomena that uncommonly coexist.

Intrapartum ultrasound for the diagnosis of cephalic malpositions and malpresentations

Fetuses with malpresentation and malposition during labor represent important clinical challenges. Women with fetuses presenting with malpresentation or malposition are at risk of increased perinatal complications, such as cesarean delivery, failure of operative vaginal delivery, neonatal acidemia, and neonatal intensive care admission. Intrapartum ultrasound has been found to be more reliable than digital examination in assessing malpresentation and malposition. The use of intrapartum ultrasound to assess fetal position and presentation, in addition to fetal attitude, to predict and aid in decision making regarding delivery can help in improving management decision making. Cephalic malpresentation and malposition is a unique subset of fetal orientation and can benefit from intrapartum ultrasound identification and assessment for delivery.

The role of the angle of progression in the prediction of the outcome of occiput posterior position in the second stage of labor

BACKGROUND

Occiput posterior position is the most frequent cephalic malposition, and its persistence at delivery is associated with a higher risk of maternal and perinatal morbidity. Diagnosis and management of occiput posterior position remain a clinical challenge. This is partly caused by our inability to predict fetuses who will spontaneously rotate into occiput anterior from those who will have persistent occiput posterior position. The angle of progression, measured with transperineal ultrasound, represents a reliable tool for the evaluation of fetal head station during labor. The relationship between the persistence of occiput posterior position and fetal head station in the second stage of labor has not been previously assessed.

OBJECTIVE

This study aimed to evaluate the role of fetal head station, as measured by the angle of progression, in the prediction of persistent occiput posterior position and the mode of delivery in the second stage of labor.

STUDY DESIGN

We recruited a nonconsecutive series of women with posterior occiput position diagnosed by transabdominal ultrasound in the second stage of labor. For each woman, a transperineal ultrasound was performed to measure the angle of progression at rest. We compared the angle of progression between women who delivered fetuses in occiput anterior position and those with persistent occiput posterior position at delivery. Receiver operating characteristics curves were performed to evaluate the accuracy of the angle of progression in the prediction of persistent occiput posterior position. Finally, we performed a multivariate logistic regression to determine independent predictors of persistent occiput posterior position.

RESULTS

Overall, 63 women were included in the analysis. Among these, 39 women (62%) delivered in occiput anterior position, whereas 24 (38%) delivered in occiput posterior position (persistent occiput posterior position). The angle of progression was significantly narrower in the persistent occiput posterior position group than in women who delivered fetuses in occiput anterior position (118.3°±12.2° vs 127.5°±10.5°; P=.003). The area under the receiver operating characteristics curve was 0.731 (95% confidence interval, 0.594-0.869) with an estimated best cutoff range of 121.5° (sensitivity of 72% and specificity of 67%). On logistic regression analysis, the angle of progression was found to be independently associated with persistence of occiput posterior position (odds ratio, 0.942; 95% confidence interval, 0.889-0.998; P=.04). Finally, women who underwent cesarean delivery had significantly narrower angle of progression than women who had a vaginal delivery (113.5°±8.1 vs 128.0°±10.7; P<.001). The area under the receiver operating characteristics curve for the prediction of cesarean delivery was 0.866 (95% confidence interval, 0.761-0.972). At multivariable logistic regression analysis including the angle of progression, parity, and gestational age at delivery, the angle of progression was found to be the only independent predictor associated with cesarean delivery (odds ratio, 0.849; 95% confidence interval, 0.775-0.0930; P<.001).

CONCLUSION

In fetuses with occiput posterior at the beginning of the second stage of labor, narrower values of the angle of progression are associated with higher rates of persistent occiput posterior position at delivery and a higher risk of cesarean delivery.

Current Resources for Evidence-Based Practice, May 2020

An extensive review of new resources to support the provision of evidence-based care for women and infants. The current column includes a discussion of a new National Academy of Medicine report on planned place of birth and implications during the SARS-CoV-2 pandemic and commentaries on reviews focused on anorectal sexually transmitted infections and feeding methods following cleft lip repair in infants.