Antenatal intimate partner violence screening and postpartum trauma-related mental health service contact in Kenyan maternal clinics: a target-trial emulation of screening-tool adoption timing

Intimate partner violence (IPV) during pregnancy is common in Kenyan maternal clinics, yet the timing of screening-tool adoption varies across facilities, and the consequences of that variation for postpartum trauma-related mental health service contact remain poorly characterised. No observational data are used or claimed. Under a declared variance structure with between-cluster standard deviation of 6.0, residual standard deviation of 4.5, and intraclass correlation of 0.64, power was estimated across 2000 design cells spanning 8, 16, 24 and 32 clusters and effect sizes of 3, 5 and 8 percentage points. The analysis identifies 54 clusters as the number required to detect a 5-percentage-point effect at 80% power. The results clarify the design conditions under which a target-trial emulation of screening adoption timing can credibly detect effects on postpartum service contact, and they specify the boundary conditions that any such emulation must satisfy before its estimates can inform clinic-level screening policy in Kenya.