2. Lennartsson J, Bengtsson C, Hallberg L, et al: Characteristics of anaemic women: the population study of women in Göteborg 1968-1969. Scand J Haematol 1979; 22: 17-24

3. Scholl TP, Hediger ML, Fischer RL, et al: Anemia vs iron deficiency: increased risk of preterm delivery in a prospective study. Am J Clin Nutr 1992; 55: 985-988

4. Murphy JF, O'Riordan J, Newcombe RG, et al: Relation of haemoglobin levels in first and second trimesters to outcome of pregnancy. Lancet 1986; 1: 992-994

5. Lao TT, Loong EP, Chin RK, et al: Relationship between newborn and maternal iron status and haematological indices. Biol Neonate 1991; 60: 303-307

6. Kullander S, Kallen B: A prospective study of drugs and pregnancy. Acta Obstet Gynecol Scand 1976; 55: 287-295

7. Knottnerus JA, Delgado LR, Knipschild PG, et al: Haematologic parameters and pregnancy outcome: a prospective cohort study in the third trimester. J Clin Epidemiol 1990; 43: 461-466

8. Agarwal KN, Agarwal DK, Mishra KP: Impact of anaemia prophylaxis in pregnancy on maternal haemoglobin, serum ferritin, and birth weight. Indian J Med Res 1991; 95: 277-280

9. Willoughby MLN: An investigation of folic acid requirements in pregnancy. II. Br J Haematol 1967; 13: 503-509

10. Hemminki E, Rimpela U: A randomized comparison of routine versus selective iron supplementation during pregnancy. J Am Coll Nutr 1991; 10: 3-10

11. U.S. Preventive Services Task Force: Routine iron supplementation during pregnancy: policy statement. JAMA 1993; 270: 2846-2848