WHY SHOULD WOMEN HAVE LOWER REFERENCE LIMITS FOR HAEMOGLOBIN AND FERRITIN CONCENTRATIONS THAN MEN?
Before puberty, no major differences are found between the sexes in red blood cell count, hemoglobin, and ferritin concentrations. Only after the onset of menses does a difference emerge. Not until 10 years after the menopause does this situation reverse in women, when the hemoglobin concentration becomes similar to that of age matched men. At present women are deemed to be anemic if their hemoglobin is less than 11.5 g/L. For men the cut point is 13.0 g/L. The situation is compounded now because modern women reach sexual maturity at an earlier age, have fewer pregnancies, and breast feed for shorter periods. Thus, they menstruate for more years. Furthermore, up to 90% of females of childbearing age do not achieve the recommended daily intake of elemental iron (15 mg). Women worldwide are at risk of being in negative iron balance. The mean upper limit for hemoglobin in primates that menstruate is significantly lower in females than in males, similar to humans. This is not the case for
