When and how do adolescent girls in Japan become aware of premenstrual symptoms from menarche? A cross-sectional study among senior high school students

Objective: To investigate the interval from menarche to the onset of premenstrual symptoms and its relationship with menarche age.

Design: Cross-sectional school-based survey.

Setting: Urban areas of Sendai, the largest city in northeastern Japan.

Participants: 1422 female Japanese 10th-12th grade senior high school students participated in the survey.

Main outcome measures: The time of awareness of premenstrual symptoms, and the interval from menarche to the onset of premenstrual symptoms.

Results: 1290 students had menstruation and completed the whole survey. The median age at menarche was 12 years (IQR: 11-13 years). The prevalence of self-reported premenstrual symptoms was 49%. The median age at which students became aware of premenstrual symptoms was 15 years (IQR: 14-16 years). The median time from the onset of menarche to awareness of premenstrual symptoms was 2 years. This time was negatively correlated with menarche age (ρ=-0.47, p<0.001). A Cox proportional hazards regression analysis revealed that early menarche was significantly associated with a lower cumulative risk of developing premenstrual symptoms (OR: 0.73 (95% CI 0.58 to 0.91)).

Conclusions: High school students in Japan began experiencing premenstrual symptoms at around 15 years old, and within 2 years of menarche. This study suggested that social factors other than hormonal factors, such as early menarche, might be associated with the onset of premenstrual symptoms.