Define Iron deficiency anaemia During pregnancy?

Iron deficiency anaemia (microcytic hypo chromic anaemia) is widespread among adolescents and young women during their reproductive years. They become highly vulnerable when greater physiological demands are imposed by pregnancy. Since the iron cost of pregnancy as shown in Table is high (1200 mg), negative iron balance tends to occur. Iron deficiency anaemia accounts for approximately 3/41h or more of the non-physiologic anaemia in pregnancy. Physiologic anaemia is a term used to indicate anaemia due to haemodilution in normal pregnancy. Based on blood volume changes during pregnancy and the iron content of foetuses  at different gestational ages, the iron requirements for pregnancy in an iron replete  non anaemic woman has been computed as shown in Table.

The increase in iron requirements during the first trimester is minimal as menstruation losses are nil and transfer to the foetus has not begun but the increase during the second and third trimester is quite large. The absorbable iron requirements are worked out to be 0.8 mg per day in the first trimester, which increases to 6.3 mg during the second and third trimesters. Assuming 5-8% absorption of iron in Indian pregnant women, the dietary iron requirement in the first trimester is 10-16 mg per day that can be easily met through existing diets. However, in the second and third trimesters, the iron need simply cannot be met through the diet as it rises to a phenomenal 80-120 mg per day. If a woman begins her pregnancy with normal iron stores of 500 mg, then the amount to be provided will reduce to 30-40 mg per day. This is the basis on which pregnant women in developed countries are recommended supplemental iron of 30 mg per day. However, among the Indian pregnant women, stores of iron are likely to be negligent. Further, most women in India are already anaemic even before the pregnancy commences. Computation of iron requirements for correction of anaemia and pregnancy needs in Indian women have been worked out and these estimates indicate that 60- 100 mg elemental iron will be needed as supplements for pregnant women. On this basis the nutritional anaemia control programme in India provides 100 mg elemental iron. One tablet daily for pregnant women  in the second and third trimesters to be continued for three more months postpartum.

The mother may not have adequate iron stores and dietary intakes may not fulfill the increased need for iron during the second half of pregnancy. Iron is required not only for haemoglobin synthesis but also to ensure adequate foetal stores that will last in the infant for the first 6 months to postnatal life. Upto 2 years of pregnancy, iron rich diets are required to replace the iron lost during pregnancy and delivery. If there is a shorter interval between pregnancies, the drain on the mother's depleted iron reserves will be even greater. Hence, it is necessary to ensure adequate iron intake. In addition to dietary intake, an iron supplement is routinely prescribed. We will need to be alert that routine iron supplements may have unpleasant gastrointestinal side effects or imbalances with other trace elements of zinc. Also excess iron intake may potentially mask inadequate pregnancy-induced haemodilution. While supplementation is needed, it is important to emphasize food sources of iron in the mother's daily diet. Certain degenerative diseases may also arise during pregnancy. The  most common ones being, hypertension and gestational diabetes. These may regress after pregnancy or continue to progress throughout life.