Prenatal Dental Hygiene Visit Uptake and Gestational Diabetes Screening Completion in Ugandan Antenatal Clinics: A Target-Trial Emulation of Care-Sequence Intervals

Gestational diabetes screening and prenatal dental hygiene visits are both recommended components of antenatal care, yet their sequence and timing are rarely examined as a joint care process. The framework specifies a before-after-control-impact design with clustering at the clinic level, and characterises its operating characteristics under a declared variance structure with an intraclass correlation of 0.64, between-cluster standard deviation of 6.0 and residual standard deviation of 4.5. 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 design requires 52 clusters to detect a 5 percentage point effect at 80% power. Care-sequence intervals can be formalised as a time-varying treatment regime, that the before-after-control-impact estimator recovers the target parameter under stated exchangeability conditions, and that cluster-level confounding by clinic scheduling practices is the principal threat to validity. The contribution is a design template for evaluating dental-hygiene-integrated antenatal care in settings where randomisation is infeasible and administrative data are incomplete.