[Iron requirements and iron balance during pregnancy. Is iron supplementation needed for pregnant women?].Ugeskr Laeger. 1997 Oct 06; 159(41):6057-62.UL
Among fertile, nonpregnant, Danish women, 33% have absent or reduced iron stores; 22% have serum ferritin values above 70 micrograms/l, i.e., iron reserves of more than 530 mg, corresponding to the net iron losses during a normal pregnancy. During pregnancy, the demands for absorbed iron increase from 0.8 to 7.5 mg/day. Controlled studies show that iron-treated pregnant women have higher serum ferritin levels, i.e., larger iron stores, and higher haemoglobin levels than placebo-treated women. A supplement of 66 mg ferrous iron daily from the beginning of the 2nd trimester prevents iron deficiency anaemia. In Denmark, general iron prophylaxis with 60-70 mg ferrous iron daily from 20 weeks of gestation is recommended by the health authorities.