Objective: Resource constraints limit the use of evidence-based clinical guidelines (CPGs). This study describes the adaptation and scale-up of a context-specific maternity care pocket guide, initially co-created in Zanzibar, to five urban health facilities in Dar es Salaam, Tanzania. Design: Participatory, iterative co-creation. Settings: Five government health facilities in Dar es Salaam (2021). Population: Maternity care providers, researchers, women and other stakeholders. Methods: A structured, flexible CPG adaptation model was applied, combining a mixed-methods situational analysis, review of global and national CPGs, and iterative feedback via focus groups and individual reviews until saturation. The guide was then pilot-tested and implemented. Main Outcome Measures: Co-creation process, PartoMa Pocket Guide and implementation strategy. Results: Two review cycles with 54 frontline providers, two external reviews (11 international experts and 10 Dar es Salaam Health Management Team members), and two consultation meetings with a 28-member core team. The process produced a 24-page infographic pocket guide of CPGs, covering routine care and common complications during childbirth, and a dissemination strategy including in-house, low-dose, high-frequency training. Using the Zanzibar guide streamlined adaptation, revealing notable consistency across resource-constrained settings. However, the process remained time- and resource-intensive, particularly when international scientific evidence was insufficient or failed to capture urban clinical complexities. Conclusions The PartoMa CPG adaptation model effectively contextualises and scales evidence-based CPGs in high-volume, resource-constrained urban settings. Global CPG developers should integrate end-user needs from the outset for more practical and cost-effective adaptations. Funding: Danida Fellowship Centre (DFC), Ministry of Foreign Affairs of Denmark (DFC project no. 18-08-KU).

Objective: To estimate the proportion of caesarean sections (CS) not meeting audit criteria for prolonged labour. Design: Cross-sectional. Setting: Five urban maternity units in Dar es Salaam, Tanzania. Population: Women giving birth by CS with an indication of prolonged labour, from October 1 st, 2021 to August 31 st, 2022. Exclusion criteria: referral to the study sites because of prolonged labour or cervical dilatation >6 cm upon admission; non-cephalic presentation; multiple pregnancy; intrauterine fetal death; failed induction; previous CS; or other reasons for CS. Methods: Criterion-based audit of CS case files with an indication of prolonged labour. Main Outcome Measure : CSs in women with uncomplicated labour progress. Results: Overall CS rate was 32% (2949/9364) and 746/1517 (47.9%) of first-time CSs were performed because of prolonged labour. Out of these, 456 met inclusion criteria and 243/456 (53.3%) CSs were in uncomplicated labour: 1) women not being given a trial of labour (78/243, 32.1%); 2) women in first stage of active labour not crossing the partograph action line (145/243, 59.7%); and 3) women in second stage less than 1 hour (20/243 8.2%). Conclusion: Almost half of CS in the unscarred uterus were because of prolonged labour and many did not meet audit criteria for prolonged labour. Crowded hospitals and inadequate monitoring may have prompted defensive decision-making. Unconducive labour wards may, therefore, indirectly drive the CS epidemic while clinical guidelines for CS decision-making remain scarce.