Iron status in 268 Danish women aged 18-30 years: influence of menstruation, contraceptive method, and iron supplementation.

The aim of the present study was to evaluate the influence of menstruation, method of contraception, and iron supplementation on iron status in young Danish women, and to assess whether iron deficiency could be predicted from the pattern of menstruation. Iron status was examined by measuring serum (S-) ferritin and hemoglobin (Hb) in 268 randomly selected, healthy, menstruating, nonpregnant Danish women aged 18-30 years. Iron deficiency (S-ferritin <16 microg/l) was observed in 9.7%, of the women, iron deficiency anemia (S-ferritin < 13 microg/l and Hb < 121 g/l) in 2.2%. Iron supplementation, predominantly as vitamin-mineral tablets containing 14-20 mg of ferrous iron was used by 35.1%. The median serum ferritin was similar in non-iron users and in iron users, whereas the prevalence of iron deficiency was 12.6% in nonusers vs. 4.3% in users, the prevalence of iron deficiency anemia 3.4% in nonusers vs. 0%, in users (p=0.17) In non-iron-supplemented women, S-ferritin levels were inversely correlated with the duration of menstrual bleeding (rs= -0.25, p<0.001) and with the women's assessment of the intensity of menstrual bleeding (r(s)= -0.27, p<0.001), whereas no such correlations were found in iron-supplemented women. The results demonstrate that even moderate daily doses of ferrous iron can influence iron status in women with small iron stores. Women using hormonal contraceptives had menstrual bleeding of significantly shorter duration than those using intrauterine devices (IUD) or other methods. There was a high prevalence of small and absent body iron stores in young women, suggesting that preventive measures should be focused on those women whose menstruation lasts 5 days or longer, who have menstrual bleeding of strong intensity, who use an IUD without gestagen, and who are blood donors.