Define Mineral Requirements during pregnancy period - Iron?
While B12 and folk acid are needed for the normal erythropoiesis, they must be accompanied by adequate amounts of other nutrients. Iron is needed for synthesis of haemoglobin in both maternal and foetal red blood cells. At term, a normal weight infant has about 246 mg of iron in blood and body stores. An additional 134 mg is stored in the placenta and about 290 mg is used to expand the volume of mother's blood.
Maintenance of erythropoiesis is one of the few instances during pregnancy when the foetus acts as a true parasite. It ensures its own production of haemoglobin by drawing iron from the mother.
We should be concerned about the mother's iron nutriture, because maternal iron deficiency may adversely affect obstetric performance. A reduction in haemoglobin concentration means that the mother must increase her cardiac output to maintain adequate oxygen supply to the placenta and the foetus. This extra work fatigues the mother and makes her more susceptible to other physiologic stress. A very low haemoglobin level places the mother at risk of cardiac arrest, and should she haemorrhage on delivery, the prognosis would be poor. The most significant known consequence of maternal iron deficiency is reduced foetal iron stores, followed by increased risk of anaemia during infancy. Moderate to severe anaemia is associated with increased risk of spontaneous abortion, premature delivery, low birth weight, still birth and perinatal death. In some cases, pica has been associated with iron deficiency. Inadequate weight gain during pregnancy has been found to be more prevalent among mothers with iron deficiency anaemia and in those with anaemias of other etiologies.
If sufficient iron is available, the mother's haemoglobin level should be at 11.5 g1100 ml by term. Most women are not able to meet the additional requirement for iron, from diet alone (since the quantity ingested is less especially in lower income settings, and the bioavailability /efficiency of absorption is very low). Thus, it is recommended that pregnant women receive an oral iron supplement. 60-100 mg of iron should maintain haemoglobin levels in normal pregnant women, but those who are anaemic will require larger doses.