The Bishop Index and Birth Outcomes in Nulliparous Women Undergoing Labor Induction: A Scoping Review.

Background: Induction of labor is one of the most common interventions in obstetrics and continues to be associated with an increased risk of cesarean delivery among nulliparous women. The Bishop Index remains widely used at admission, but its predictive power when used in isolation is limited. Objectives: To map the available scientific evidence on the use of the Bishop Index at admission as an indicator of obstetric outcomes in nulliparous women undergoing labor induction. Methods: A scoping review was conducted in accordance with the Joanna Briggs Institute methodology and the PRISMA-ScR reporting guidelines. The search strategy was structured according to the PCC (Population, Concept, Context) mnemonic and covered the PUBMED (Public MEDLINE), Scopus, and Web of Science databases, as well as the CINAHL Ultimate, Medic Latina, and MEDLINE Ultimate databases on the EBSCOhost platform, with no time restrictions and limited to the English, Portuguese, Spanish, and French languages. A critical methodological appraisal was conducted as a complementary procedure to support the interpretation of the results. The protocol is registered on the OSF (Open Science Framework) platform with the DOI: 10.17605/OSF.IO/WYE24. Results: The 38 eligible studies were included in the overall mapping; the JBI methodological assessment was used only as a supplementary procedure to contextualize the strength of the evidence, and 21 studies with a JBI score of ≥75% were prioritized solely for an in-depth interpretive synthesis. These studies span the period from 1992 to 2026, with a diversity of study designs and geographic contexts, allowing for a characterization of the use of the Bishop Index in the process of labor induction in nulliparous women and the resulting obstetric outcomes. Conclusions: The evidence confirms the clinical utility of the Bishop Index as a bedside tool but reveals significant heterogeneity among studies, definitions of success, and induction methods. When reported, predictive performance indicators tended to favor combined models and ultrasound parameters over the use of the Bishop Index alone. The most recent studies point to the potential of ultrasound parameters and combined models to improve the predictive capacity of obstetric outcomes.