Recruitment
PMS
PMS
This study was conducted in two stages from December 2020 to September 2021 in Sari, northern Iran. The first step involved identifying students with moderate to severe PMS using Premenstrual Symptoms Screening Tool. By referring to six purposefully selected schools in Sari (among the 14 high schools), the census sampling method was employed to assess the PMS severity of 504 students. At this stage, 408 students were excluded from the study (405 students not meeting inclusion criteria and three students declined to participate). Then, 96 eligible students, who were willing to participate in the study, entered the second stage of the study. Among them, six students of a school with better power of speech and good communication skills (according to the school counselor and principal's viewpoint) were selected as peer educators, and 30 students from the same school were included in the first intervention group (education by peers). From the rest of the eligible students, with the assistance of a random number table, 30 students were selected as the second intervention group (education by a healthcare provider) and 30 students as the control group. In the follow‐up phase, no samples were lost in the groups.