Expanding the Evidence Base for Cervical Ripening: Aggregate Data Analysis as Part of the CIRCLE-NMA Initiative

Meta-analysis represents the highest level of evidence synthesis. Induction of labour is among the most frequently performed obstetric procedures worldwide, undertaken when delivery is deemed more beneficial than continuing the pregnancy. However, it remains unclear which cervical ripening method offers the greatest effectiveness and safety. The CIRCLE-NMA project is an individual participant data (IPD) meta-analysis initiative designed to evaluate and rank all cervical ripening methods within a single analytical framework.1 However, complete IPD collection is not always feasible, due to factors such as data-sharing restrictions, ethical considerations, or the unavailability of datasets. Exclusion of such studies from the network risks the loss of potentially important information. To mitigate this, a complementary project will incorporate aggregated data from trials that cannot contribute IPD. This work involves systematically extracting obstetric, maternal, and neonatal outcomes from publications, and adding granularity by categorising them into meaningful subgroups, such as inpatient versus outpatient settings, route of administration, dosage, or the socioeconomic context of the trial. In addition, the project will include conducting structured risk of bias assessments to evaluate the methodological quality of the included studies. Through your contribution, you will help address the key clinical question: which cervical ripening methods are most effective, and in which types of patients or clinical settings? You will also gain valuable skills in evidence synthesis, develop knowledge in obstetrics related to induction of labour, and build experience in statistical analysis and practical data handling. 1. CIRCLE-NMA. Cervical Ripening for Induction of Labour: Collaborative Evidence in Network Meta-Analysis. Accessed October 10, 2025. https://circlenma.com/