Abstract
BACKGROUND AND AIM: Menstrual irregularities affect women's physiological, psychological, and reproductive health, yet remain understudied among university students in Bangladesh. This study aimed to assess menstrual characteristics using a composite menstrual irregularity (CMI) score and identified key determinants among female undergraduates in Chittagong. METHODS: An institution-based cross-sectional study was conducted among 469 female undergraduates from three universities in Chittagong, Bangladesh (September 2024-May 2025). The CMI score and Perceived Stress Scale (PSS-10) were used for assessing menstrual irregularity and stress level respectively. Multivariable logistic regression models have been applied; results are shown as adjusted odds ratios (AORs) with 95% confidence intervals (CIs). RESULTS: Of 469 participants (240 non-medical, 229 medical; median age 22 years [IQR 21-23]), 81.2% met CMI-1 (mild irregularity), 45.5% met CMI-2 (moderate irregularity), and 16.9% met CMI-3 (severe irregularity). Metrorrhagia was the strongest predictor across all thresholds (CMI-1: AOR 4.37 [1.26-27.65]; CMI-2: AOR 3.12 [1.53-6.71]; CMI-3: AOR 3.27 [1.53-6.83]; all p < 0.05). Middle-range income (20,000-40,000 BDT) elevated CMI-1 odds (AOR 5.52 [1.78-17.88]; p = 0.003). In stratified analyzes, late menarche predicted irregularity exclusively among non-medical students (CMI-1: AOR 2.71 [1.22-6.50]; CMI-2: AOR 1.93 [1.06-3.57]; CMI-3: AOR 2.37 [1.08-5.31]; all p < 0.05); married status was protective against CMI-2 in non-medical students (AOR 0.24 [0.08-0.65]; p = 0.006); and hostel residence increased CMI-2 odds in medical students (AOR 2.73 [1.17-6.72]; p = 0.023). High perceived stress was not independently associated with any threshold. The Internet and mass media were the primary sources of menstrual knowledge (52.5%). CONCLUSIONS: Menstrual irregularity is prevalent and multidimensionally patterned among female undergraduates in Bangladesh. Perceived stress, though elevated among non-medical students, was not independently associated with irregularity in adjusted models. Metrorrhagia, income, late menarche, and living arrangements are key modifiable factors. These findings support targeted university health interventions and evidence-based menstrual health policies in Bangladesh.