A Study on Menarchel Age and Monthly Incidence of School Girls in Ansan

ABSTRACT

PURPOSE: Menarche is an important life event, making the transition from childhood to early womanhood. It is a significant physical and physiological event that adolescent girls feel sexual identity and it affects on psychological development. The onset of menstruation is considered a practical indication of sexual maturity in girls. On a population level, mean menarcheal age is considered to be primarily an indicator of living conditions and health. The purpose of this study is to determine menarcheal age in Ansan, Korea in present time and confirm and analize the seasonal variation in menarche in Ansan, Korea. METHODS: The cross-sectional study was done on menarche in 4,786 junior high and high school girl students (11-20years old) of Ansan city. RESULTS: 1) The mean menarcheal age was 12.4+/-1.1 years. 2) The menarcheal ages of 12-year-old, 16-year-old, and 20-year-old girls were 11.4+/-0.7, 12.3+/-0.9, 13.2+/-1.1 respectively. These data show earlier onset of menarche at the younger age groups with statistical significance at p<0.01. 3) The menarche occurred most frequently on August (14.9%), followed by July (12.1%), January (10.2%), December (9.7%). CONCLUSIONS: The mean menarcheal age of the subjects was 12.4+/-1.1 years and it was not different from the mean age of menarche in Europe and United States. These data showed that there was a seasonal variation in the onset of menarche, peak in the summer and winter and it seems to be affected complicatedly by many factors such as seasonal factor, phylogenetic factor ontogenetic factor, environmental factor, psychologic status, nutritional status etc.