Favorable Simplified Bishop Score after cervical ripening associated with decreased cesarean birth rate

  • Author Footnotes
    a UCLA OB/GYN, 10833 Le Conte Ave, #CHS27139, Los Angeles, CA 90095
    Daniel S LEE
    Correspondence
    Corresponding author contact: Daniel S Lee, 1900 Sawtelle Blvd, Apt 404, Los Angeles, CA 90025, (360)823-8963
    Footnotes
    a UCLA OB/GYN, 10833 Le Conte Ave, #CHS27139, Los Angeles, CA 90095
    Affiliations
    Department of Obstetrics and Gynecology, David Geffen School of Medicine, University of California at Los Angeles, Los Angeles, California
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  • Ms. Megha D TANDEL
    Affiliations
    Department of Urology, David Geffen School of Medicine, University of California at Los Angeles, Los Angeles, California
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  • Ms. Lorna KWAN
    Affiliations
    Department of Urology, David Geffen School of Medicine, University of California at Los Angeles, Los Angeles, California
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  • Alex A FRANCOEUR
    Affiliations
    Department of Obstetrics and Gynecology, David Geffen School of Medicine, University of California at Los Angeles, Los Angeles, California
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  • Hai-Lang DUONG
    Affiliations
    Department of Obstetrics and Gynecology, David Geffen School of Medicine, University of California at Los Angeles, Los Angeles, California

    Department of Obstetrics and Gynecology, Olive View–UCLA Medical Center, Sylmar, California
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  • Masaru NEGI
    Affiliations
    Department of Obstetrics and Gynecology, David Geffen School of Medicine, University of California at Los Angeles, Los Angeles, California

    Department of Obstetrics and Gynecology, Olive View–UCLA Medical Center, Sylmar, California
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  • Author Footnotes
    a UCLA OB/GYN, 10833 Le Conte Ave, #CHS27139, Los Angeles, CA 90095
Published:November 19, 2021DOI:https://doi.org/10.1016/j.ajogmf.2021.100534

      Abstract

      Background: A favorable Simplified Bishop Score (>5) before induction of labor is associated with successful vaginal birth. Patients with an unfavorable Simplified Bishop Score ( 5) undergo cervical ripening prior to administration of oxytocin. However, data are limited regarding the utility of the Simplified Bishop Score after cervical ripening.
      Objective(s): The objective of this study is to determine if the Simplified Bishop Score prior to oxytocin induction, but after cervical ripening, is associated with cesarean birth.
      Study Design: We conducted a retrospective cohort study on patients undergoing induction of labor from the Consortium on Safe Labor. Patients with a singleton term pregnancy who initially underwent cervical ripening were included. Those with a history of cesarean birth were excluded. Outcomes of patients with a favorable Simplified Bishop Score after cervical ripening were compared to those with an unfavorable Simplified Bishop Score. Primary outcome was mode of birth. Log-binomial regression was performed to calculate relative risk and control for confounders, such as admission Simplified Bishop Score and parity.
      Results: A total of 5,807 patients met criteria to be included in the study. 4,235 (73%) patients had a favorable cervix and 1,572 (27%) patients had an unfavorable cervix after cervical ripening.
      The favorable group had a decreased rate of cesarean birth compared to the unfavorable group (RR 0.35, 95% CI: 0.30, 0.40). Both groups had low rates of maternal chorioamnionitis, though patients with unfavorable cervix were at higher risk. There was no significant difference in rates of postpartum hemorrhage or NICU admission.
      Lower rates of cesarean birth among the favorable group persisted when stratifying by parity (nulliparous: RR 0.37, 95% CI: 0.31, 0.43; multiparous: RR 0.22, 95% CI: 0.14, 0.36). After controlling for maternal age, pre-pregnancy BMI, parity, gestational age, and Simplified Bishop Score at admission, a favorable cervix remained significantly associated with fewer cesarean births (RR 0.55, 95% CI: 0.46, 0.66).
      Conclusion(s): In women undergoing labor induction, a favorable Simplified Bishop Score after cervical ripening and before the start of oxytocin is associated with decreased rate of cesarean birth, even after adjusting for parity and Simplified Bishop Score on admission. Also, Simplified Bishop Score assigned after cervical ripening could be used to inform timing of oxytocin initiation. However, further research is necessary to determine the ideal endpoint of cervical ripening.

      Keywords

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