Indigenous Midwifery Apprenticeship Exposure and Psychological Birth Trauma in Ghanaian Traditional Birth Attendant Communities: A Difference-in-Differences Estimation of Ritual Knowledge Transmission and Maternal Distress

Psychological birth trauma among mothers served by traditional birth attendants (TBAs) in Ghana remains poorly understood, and the role of indigenous midwifery apprenticeship in shaping maternal distress is contested. Because no primary observational data were available, the study characterises the operating characteristics of a before-after-control-impact (BACI) design under a declared variance structure. The design assumed a between-cluster standard deviation of 6.0, a residual standard deviation of 4.5, and an intraclass correlation of 0.640. Power was estimated across 2000 replications per design cell for cluster counts of 8, 16, 24 and 32 and effect sizes of 3, 5 and 8 percentage points. The analysis indicates that 54 clusters are required to detect a 5-percentage-point effect at 80% power. Minimum detectable effect curves and power curves are reported. Apprenticeship exposure should be operationalised as a community-level ritual transmission variable, and that BACI designs can credibly identify its effect on maternal distress only when cluster counts exceed conventional thresholds. The contribution is a design framework for studying indigenous knowledge transmission and psychological outcomes in low-resource settings.