Statistical analysis
REGRESSION
Power calculations were conducted a priori based on the primary study outcome, modern contraceptive use. We assumed an intra-cluster correlation coefficient of kappa = 0.05. To provide 80% power at capturing an effect size of 2.0 greater odds of modern contraceptive use across four arms with 12 clusters of equal size nested within each arm, with 10% anticipated attrition, and 95% confidence, we calculated that 300 couples would be required at baseline (1200 wives and their husbands) [Changes between baseline and follow-up comparing intervention arms to the control condition were assessed with an intention to treat, difference-in-difference Poisson regression approach, using mixed-effects models with nested random effects accounting for village-level clustering. Minimally adjusted models accounted only for time (baseline or follow-up), treatment status or study arm, district, and a time-treatment interaction term. Such models were constructed both considering combined treatment status (i.e. control vs. pooled intervention arms) and specific study arm (i.e. control vs. Arm 1 vs. Arm 2 vs. Arm 3). Fully adjusted models included baseline demographic characteristics as fixed effects in outcome models if they were associated with treatment or female loss to follow-up in Fisher’s exact tests or ANOVA tests at p < 0.20; female loss to follow-up was used because female data defined outcome measures. Fixed effects in these models thus included baseline values of wife age at marriage, wife education, husband education, wife parity, husband polygamy, husband migration for more than 3 months of the previous year, and household asset ownership (watch, mobile phone, bicycle, motor bike/scooter, car/truck, animal-drawn cart). Wife’s age was included based on documented associations and programmatic interest [Based on the importance of women’s age and parity in reproductive autonomy and IPV [We conducted all analyses using STATA 15.1. Significance was set at p < 0.05 for all Fisher’s exact tests, ANOVA tests, and incident rate ratios (IRRs); 95% confidence intervals (CIs) are reported throughout. This trial is registered with ClinicalTrials.gov, Identifier NCT03226730.