RESUMEN
BACKGROUND: Menstrual cycle characteristics have been studied throughout the world in several populations. OBJECTIVE: To analyze the frequency of occurrence of menstruation, duration and volume loss during it and its relationship with age, weight and body fat distribution in Mexican women. MATERIAL AND METHODS: prospective, cross-sectional and descriptive study conduced in women which accompanied patients to hospital consultation, with menstrual cycles considered normal by them, age was documented; body mass index (BMI) and waist hip ratio (WHR) were calculated. They were questioned about: periodicity of the cycle, duration, number and type of pads used per day, and the quantity of menstrual bleeding was calculated. STATISTICAL ANALYSIS: Central tendency and dispersion measurements, as well as percentages were calculated. For the comparison between the groups ANOVA was used and Pearson correlation analysis was done. RESULTS: 161 women were studied. Average age was 23.9 +/- 6.1 years, BMI 26.1 +/- 4.3 and WHR 0.9 +/- 0.1. The cycle periodicity was 29.3 +/- 3.1 days, being 86.4% between 28 and 30 days. The periodicity of menstrual bleeding was affected neither by age nor by BMI and WHR. Bleeding duration was 4.9 +/- 1.6 days, and the most common was from 4-7 days, only in those older than 35 years was from 1-3 days. The calculated average volume was 151.5 +/- 81.0 mL. In those with BMI < 20 loses were between 81and 120 ml, and in those with BMI > 35 from 121-160 ml; 85.5% of women with WHR < or = 0.85 had loses between 81 and 160 ml and 39.3% of those with WHR > 0.85. CONCLUSION: BMI greater than 35 is associated with more abundant bleeding, and android distribution of body fat with smaller bleeding.