The Association between the maternal dietary iron intake (Hem, Non-Hem, and Total iron) during the first trimester of pregnancy and pregnancy-related complications and pregnancy outcomes

Dietary iron is in two forms: hem and non-hem iron (Total iron is the mixture of hem and non-hem) most of the dietary iron intake in Asiatic country e.g. Iran are non-hem iron and are from plant sources (۲۱). The amount of non-hem iron absorption is very low and related to the individual's body reserves and other dietary components such as ascorbic acid, calcium (۲۳) and hem-iron (۲۰). Hem iron has a higher bioavailability in a body and is well absorbed (۲۲) but it can be a little influenced by the other dietary components (۲۴). Recent researches suggest that hem and non-hem iron may have various associations with health outcomes (۲۴).Iron deficiency is the most common nutritional problem in the world, especially during the pregnancy period (۱). As a reason for increasing iron requirements during pregnancy, pregnant women are considered as a vulnerable group in iron deficiency anemia (۲). This issue correlated with adverse pregnancy problems and outcomes such as infant's mortality and morbidity, small for gestational age (SGA), preterm birth (PT), delayed offspring neurological development, low birth weight (LBW)(۳) and could be correlated with low iron stores and poor health of infants, especially diagnosing during the first half of pregnancy (۳, ۴)..The result of some animal study shows that low iron intake during pregnancy has negative effects on the offspring’s blood pressure, obesity levels and cardiovascular disease in the long term (۵, ۳۸, and ۴۲).The etiology of iron deficiency anemia is multifactorial and include nutritional deficiency (the most common cause of anemia), chronic inflammation, parasitic infection, genetic factors and socioeconomic status (۶). Iron supplementation is widely recommended and used during pregnancy in worldwide to prevent anemia (۷). However, the iron supplementation effect on the pregnancy- related complications and pregnancy outcome has not been clearly identified (۶, ۸).