Korelasi Usia Menarche Dengan Keteraturan Siklus Menstruasi Pada Siswi SMP

Early or delayed menarche may reflect differences in pubertal and hormonal maturation that are associated with menstrual cycle regularity during adolescence. This study aimed to analyze the relationship between age at menarche and menstrual cycle patterns among female students at SMPN 1 Lumbang, Pasuruan Regency, East Java. An analytical observational design with a cross-sectional approach was used. The population consisted of 77 female students in grades VII, VIII, and IX, and 65 respondents were selected using proportional random sampling. The independent variable was age at menarche, categorized as early and normal, while the dependent variable was menstrual cycle pattern, categorized as normal and abnormal. Primary data were collected using a structured questionnaire and analyzed through univariate analysis and the Chi-Square test. The strength of association was additionally estimated using an unadjusted odds ratio (OR) with a 95% confidence interval (CI) and Phi coefficient. Most respondents experienced menarche at the normal age of 12-14 years (45 students; 69.2%), while 20 respondents (30.8%) experienced early menarche. Most respondents had a normal menstrual cycle of 21-35 days (55 students; 84.6%), whereas 10 respondents (15.4%) had abnormal cycles. The Chi-Square test indicated a significant relationship between age at menarche and menstrual cycle pattern (p = 0.003). Students with early menarche had higher odds of experiencing abnormal menstrual cycles compared with those with normal-age menarche (OR = 7.54; 95% CI: 1.70–33.41; Phi = 0.362). These findings highlight the need for school-based reproductive health education and early monitoring of menstrual cycle patterns among adolescent girls.