RESUMEN
OBJECTIVE: To determine the normal limits of menstrual fluid volume during reproductive life, quantified by direct measurement. METHODS: This was an observational, prospective clinical trial of healthy women aged 20-49 years old, with normal menstrual periods, recruited in a Natural Family Planning Unit. Women collected their menstrual fluid for at least 3 menstrual periods using a vaginal cup. Menstrual volume and different covariables were evaluated using a multilevel mixed-effects linear regression. RESULTS: Ninety-six cycles from 28 patients between 24 and 49 years old were analyzed. The average menstrual volume was 86.7 mL with a range from 15 to 271 mL. The 50th percentile of all samples was 81 mL and the 95th percentile was 162 mL. For multiparous patients the 50th percentile was 93 mL and the 95th was 169 mL. Menstrual fluid volume was higher in multigravida (99.1 mL) than in nulliparous women (45.9 Ml; p < 0.02). No statistically significant associations were identified between different variables and menstrual volume. CONCLUSION: A menstrual volume over 169 mL should be considered abnormal on multiparous patients. Age was not associated with changes on menstrual fluid volume.