Sample size determination and sampling procedures

Sample size was calculated by using EPI-info with the assumptions of prevalence: 50%, margin of error: 5%, and 95% CI. By adding a 10% non-response rate, final sample size was 422. Based on the previous two months’ performance of health facilities that provide legal termination of pregnancy, proportional allocations were made. Systematic random sampling was implemented to select study participants. The interval of K was calculated by dividing each health institution’s two months client flow by required sample size allocated for each institution. Purposively 13 individuals were selected based on individuals’ age, marital status, and frequency of pregnancy termination for in-depth interviews.