Iron

Pregnancy is a physiological occasion primarily causing oxidative stress, mostly because of the mitochondria-rich placenta . Pregnant women are more prone to oxidative stress as a result of an imbalance between the pro-oxidant-antioxidant levels. Under normal conditions, the cells develop a number of counteracting antioxidant defenses. Free radical scavenging mechanisms include both enzymatic and nonenzymatic antioxidants that limit the cellular concentration of free radical and prevent excessive oxidative stress ].

Iron deficiency anemia (IDA) (low Hb and serum ferritin values) is the most prevalent deficiency anemia in pregnant women. IDA has been associated with increased risks for prematurity, low birth weight, and maternal morbidity [4]. Iron is required by the enzymes involved in oxidative metabolism [5]. In addition, iron requirements increase during pregnancy [6], and this may lead to anemia in pregnant women [7].

Maternal anemia before midpregnancy is associated with increased risk for preterm birth. Maternal anemia during the third trimester is usually not associated with an increased risk for adverse pregnancy outcomes and may be an indicator of an expanded maternal plasma volume. In contrast, high levels of hemoglobin, hematocrit, and ferritin are associated with an increased risk for pre-eclampsia, gestational diabetes mellitus, fetal growth restriction, and preterm delivery [1].

Ferrous iron used for oral iron therapy in pregnancy is a potent pro-oxidant, and many studies suggested that iron-deficient women were more susceptible to this iron therapy-induced oxidative stress [8]. About 3-5% of the iron present in the alimentary canal in ferrous form is absorbed. Acidic milieu facilitates iron absorption by keeping iron in ferrous form. Ferrous iron is a central pro-oxidant that propagates free radical reactions through Fenton chemistry both locally and systemically [9]. Consequently, although iron supplementation may improve pregnancy outcome when the mother is iron deficient, it is probable that prophylactic supplementation may increase risk when the mother does not have iron deficiency or IDA [1].

Oral iron is frequently used as a first-line therapy, but iron salts such as ferrous sulfate are associated with a high incidence of gastrointestinal side effects. However, a ferric (Fe 3+ ) iron polymaltose complex (IPC) contains iron in a nonionic form that provides similar iron bioavailability as ferrous sulfate but has a stable structure that has more controlled absorption of iron, thus making it less toxic [10]. The available data comparing IPC versus ferrous sulfate in pregnant women suggest that efficacy is similar with the two preparations, but randomized trials are rarer than that in adults and long-term data are lacking [11].

Supplementation with iron obviously augments iron status and iron stores. There are few studies on whether supplementation during pregnancy increases oxidative stress and whether the nature of oral iron supplementation (ionized and nonionized) has the same effect on the index of systemic inflammation and oxidative stress defense mechanisms in maternal blood.