Anemia is the single most common hematological problem faced by women. The most common anemia are iron deficiency anemia and folate deficiency megaloblastic anemia. Iron deficiency alone affects nearly 20% of the world's population. Approximately 51% of pregnant women are anemic. This includes a prevalence of 56% in developing countries and 18% in developed countries. Among these, 43% of women from developing countries and 12% of women from developed countries were already anemic, preconception. The WHO has estimated that considering all forms of anemia, from 16,800 to 28,000 women of reproductive age die annually from anemia, with the greatest risk in younger women. Of all anemias diagnosed during pregnancy, 75% are due to iron deficiency.

The systemic effects of anemia of any cause may result in significant morbidity. Deficiencies of iron, folate and vitamin B12 result in unique clinical consequences. These are manifested throughout life. The underlying etiologies of each deficiency state may be somewhat different pre-puberty, during the child bearing years and post menopause. During pregnancy, the adverse effects of iron, folate and vitamin B12 deficiency extend beyond the health of the mother to the developing fetus. This chapter is divided into two sections. The first reviews the most common type of anemia, iron deficiency. The second section examines the deficiencies of folate and vitamin B12. Because of the close interrelationship between folate, vitamin B12 and homocysteine in the methionine synthesis pathway, hyperhomocysteinemia is also discussed.