Why should women have lower reference limits for haemoglobin and ferritin concentrations than men?

Association between serum ferritin levels and the incidence of obesity in Korean men: A prospective cohort study

“…Mean serum ferritin levels are generally lower in women than in men; this is probably attributable to menstrual iron loss in women. Thus, our results cannot be extrapolated to women, and further studies are necessary [33]. Although there have been several reports about the relationship between serum ferritin levels and metabolic syndrome [3,4,6,22], there has been no direct evidence whether serum ferritin is a predictor of development of obesity or not.…”

Serum Ferritin Level is an Independent Predictor of Insulin Resistance in Non-diabetic Men Aged Between 30-69 Years: Korean National Health and Nutrition Examination Survey 2008-2010

“…31 Significantly lower serum level of ferritin in women compared to men in our study might be caused by the menstrual iron loss in women.…”

Effect of iron supplementation on fatigue in nonanemic menstruating women with low ferritin: a randomized controlled trial

“…3 However, the hemoglobin levels of these patients were not available, which may have contributed to the ongoing debate about the appropriateness of reference limits defining anemia in women. 4,5 Thus, the effectiveness of iron supplementation in nonanemic menstruating women with major fatigue without an obvious clinical cause is unknown. 6 Our main objective was to test the hypothesis that oral iron therapy for a short period may improve fatigue, hemoglobin, iron stores and quality of life in menstruating nonanemic women whose ferritin levels are below 50 µg/L.…”