Micronutrition in pregnancy ( Part 3 )

 

Iodine is an essential nutrient for regulating growth, development and metobolism via biosyntesis of thyroid hormones including T4 and T3 .Iodine is obtained mainly from fortified salt but it can be sourced from kelp and seefood as well as dairy or plant foods in places with iodine-fortified animal feed or iodine -rich soil.This is because early in pregnany thyroid hormone production increases by % 50 and renal excretion of iodine increase by % 30-50 , while later in gestation , iodine passes the placenta for fetal thyroid hormone production.Maternal and fetal thyroid hormones regulate key processes    in teh development of the fetal brain and vervous system, including the growth of nerve cells,required to prevent deficiency , yet iodine deficiency disorder remain the most common cause of preventable brain and cognitive impairment worldwide.

Other consequences of iodine deficiency disorder in pregnancy include fetal and maternal goitre,lower intelligence scores,increased pregnancy loss and infant mortality.

Hence , a dietary iodine intake of 250 microgram / day is recommed for pregnant and lactating women  .

Iron is a vital nutritient and cofactor for thr syntesis of haemoglobin and myoglobin , as well as for several cellular functions including oxygen transport,respiration,growth,gene regulation,and the proper functioning of iron dependent enzymes.

Plant based foods such as green leafy vegetables contain non heam iron, which makes up the major fraction of dietary iron.However , haem iron from foods such as animal meats and fish has a higher bioavailability and is absorbed more efficiently , making the main source of dietary iron for animals.

In pregnancy the demand of iron increases  although the exact upper limits in the third trimester.

maternal iron requirements therefore exceed avarage absorbable iron intakes and the risk of developing iron deficiency anemia is increased in pregnancy.

Iron deficiency have been associated with greater risk of preterm birht,low birht weight baby,impaired maternal function and decreased defence against infection as well as abnormal phychomotor development and cognitive function in infancy.commen

Preconceptional supplementation with 30-60 mg/ day of elemental iron is recommended for women during pregnancy