Objective: Menorrhagia is defined as blood loss of >80 mL, but in routine clinical practice measurement is seldom undertaken. Our aim was to identify the features of the clinical history that best predict menorrhagic blood loss.
Study design: A questionnaire survey of 952 menstrual complaint referrals at 3 hospital gynecology clinics in Glasgow and Edinburgh included 226 women with putatively heavy periods who also had consented to the measurement of their blood loss.
Results: Only 34% (95% CI, 28%-40%) of women had blood loss volume of >80 mL, but the volume was associated with subjective heaviness of period. Logistic regression with ferritin status, clots, and changing rate during full flow correctly predicts a loss of >80 mL for 76% of women (n=161 patients; sensitivity, 60%; specificity, 86%). Diagnosis and treatment of patients seem unrelated to the volume of blood loss.
Conclusion: The subjective judgment of the volume of blood loss is better than has been believed. Clinical features can be combined to predict losses of >80 mL.