Subgroup analysis
Statistical analyses were conducted among the subgroup of adolescent girls without hormonal contraceptives (n=644) and showed similar results: the prevalence of dysmenorrhea was 92.4% (n=595), with severe dysmenorrhea occurring in 6.8% (n=44) (Appendix 2). More adolescents in this group had heavier menstrual periods (p= .042) and inter-menstrual pain (p <.001) than the whole cohort of girls with dysmenorrhea.