Utility of the Simplified Bishop Score in Spontaneous Labor

Abstract

Objective The objective of this study was to evaluate the relationship between the simplified Bishop score (SBS) on admission for labor and subsequent labor outcomes to identify women at higher risk for cesareans.

Study Design This was a secondary analysis of a prospective cohort study of 4,733 singleton pregnancies. Adjusted odds ratios (aOR) were calculated comparing outcomes in women with an unfavorable SBS ≤ 5 to women with a favorable SBS > 5. A favorable SBS was compared with the individual parameters of dilation, effacement, and station. The primary outcome was vaginal delivery. Secondary outcomes were prolonged first stage, completion of first stage, oxytocin augmentation, and prolonged second stage.

Results 47.8% of the patients admitted in labor had an unfavorable SBS. Nulliparous and multiparous patients with a favorable SBS were more likely to have a vaginal delivery (aOR 1.96, 95% confidence intervals [CI] 1.49–2.57; aOR 1.91, 95% CI 1.44–2.53) and less likely to require oxytocin augmentation (aOR 0.34, 95% CI 0.28–0.42; aOR 0.26, 95% CI 0.22–0.30. Compared with dilation alone, the SBS in its entirety was associated with a higher likelihood of vaginal delivery in nulliparous.

Conclusion An unfavorable SBS on admission for labor is associated with a decreased likelihood of having a vaginal delivery.

Keywords

Bishop score - cervical dilation - effacement - fetal station - labor

• References

• 1 Bishop EH. Pelvic scoring for elective induction. Obstet Gynecol 1964; 24: 266-268
• 2 Burnett Jr JE. Preinduction scoring: an objective approach to induction of labor. Obstet Gynecol 1966; 28 (4) 479-483
• 3 Vrouenraets FP, Roumen FJ, Dehing CJ, van den Akker ES, Aarts MJ, Scheve EJ. Bishop score and risk of cesarean delivery after induction of labor in nulliparous women. Obstet Gynecol 2005; 105 (4) 690-697
• 4 Vahratian A, Zhang J, Troendle JF, Sciscione AC, Hoffman MK. Labor progression and risk of cesarean delivery in electively induced nulliparas. Obstet Gynecol 2005; 105 (4) 698-704
• 5 Johnson DP, Davis NR, Brown AJ. Risk of cesarean delivery after induction at term in nulliparous women with an unfavorable cervix. Am J Obstet Gynecol 2003; 188 (6) 1565-1569 , discussion 1569–1572
• 6 Friedman EA, Niswander KR, Bayonet-Rivera NP, Sachtleben MR ; EA F. Relation of prelabor evaluation to inducibility and the course of labor. Obstet Gynecol 1966; 28 (4) 495-501
• 7 Lange AP, Secher NJ, Westergaard JG, Skovgård I. Prelabor evaluation of inducibility. Obstet Gynecol 1982; 60 (2) 137-147
• 8 Laughon SK, Zhang J, Troendle J, Sun L, Reddy UM. Using a simplified Bishop score to predict vaginal delivery. Obstet Gynecol 2011; 117 (4) 805-811
• 9 DeLong ER, DeLong DM, Clarke-Pearson DL. Comparing the areas under two or more correlated receiver operating characteristic curves: a nonparametric approach. Biometrics 1988; 44 (3) 837-845
• 10 Reis FM, Gervasi MT, Florio P , et al. Prediction of successful induction of labor at term: role of clinical history, digital examination, ultrasound assessment of the cervix, and fetal fibronectin assay. Am J Obstet Gynecol 2003; 189 (5) 1361-1367
• 11 Kehila M, Bougmiza I, Ben Hmid R, Abdelfatteh W, Mahjoub S, Channoufi MB. Bishop Score vs. ultrasound cervical length in the prediction of cervical ripening success and vaginal delivery in nulliparous women. Minerva Ginecol 2015; 67 (6) 499-505
• 12 Park KH, Kim SN, Lee SY, Jeong EH, Jung HJ, Oh KJ. Comparison between sonographic cervical length and Bishop score in preinduction cervical assessment: a randomized trial. Ultrasound Obstet Gynecol 2011; 38 (2) 198-204
• 13 Pandis GK, Papageorghiou AT, Ramanathan VG, Thompson MO, Nicolaides KH. Preinduction sonographic measurement of cervical length in the prediction of successful induction of labor. Ultrasound Obstet Gynecol 2001; 18 (6) 623-628
• 14 Segel SY, Carreño CA, Weiner SJ , et al; Eunice Kennedy Shriver National Institute of Child Health and Human Development Maternal-Fetal Medicine Units Network. Relationship between fetal station and successful vaginal delivery in nulliparous women. Am J Perinatol 2012; 29 (9) 723-730
• 15 Caughey AB, Cahill AG, Guise JM, Rouse DJ ; American College of Obstetricians and Gynecologists (College); Society for Maternal-Fetal Medicine. Safe prevention of the primary cesarean delivery. Am J Obstet Gynecol 2014; 210 (3) 179-193
• 16 Barber EL, Lundsberg LS, Belanger K, Pettker CM, Funai EF, Illuzzi JL. Indications contributing to the increasing cesarean delivery rate. Obstet Gynecol 2011; 118 (1) 29-38
• 17 Zhang J, Landy HJ, Branch DW , et al; Consortium on Safe Labor. Contemporary patterns of spontaneous labor with normal neonatal outcomes. Obstet Gynecol 2010; 116 (6) 1281-1287