It is well known that iron is involved in the synthesis of hemoglobin, but in addition, iron also plays an important role in the endocrine system, and can even affect the development of the fetal nervous system. Therefore, don’t be fooled into thinking that iron deficiency only causes anemia. Especially pregnant women, should pay more attention to this point. 1, iron deficiency during pregnancy, the danger of pregnant women nausea, vomiting and other pregnancy reactions may occur after the iron intake is insufficient, coupled with the increase in blood volume, blood dilution, fetal synthesis of hemoglobin also need iron, iron deficiency during pregnancy relative to normal people are more common. About 1/3 of pregnant women have iron deficiency. Iron deficiency is harmful and can increase the incidence of thyroid disorders, making the risk of miscarriage, preterm labor, and low birth weight babies higher. According to a prospective Belgian study, iron deficiency in pregnant women increased the risk of thyroid autoimmune disease by 50%. The study was published on July 22, 2016, in the European Journal of Endocrinology. The study covered 1,900 pregnant women, 35 percent of whom developed iron deficiency in early pregnancy. None of the study participants had a history of thyroid disease or related medications, and those taking iron supplements were also excluded. Ferritin, thyroid peroxidase antibodies (TPO-abs), thyroid stimulating hormone (TSH), and free thyroxine (FT4) were measured at the first labor and delivery visit, and maternal age and body mass index were recorded. In judging the results, the investigators defined iron deficiency criteria as serum ferritin <15 µg/ml, thyroid autoimmunity as TPO >60 kIU/L, and subclinical hypothyroidism as TSH >2.5 mIU/L. The results showed that 35% of pregnant women were iron-deficient, and that the deficiency was independent of age and weight. Comparison of iron deficiency and no iron deficiency pregnant women, the researchers also found that iron deficiency group there are high TSH, low FT4, and thyroid autoimmunity and the incidence of subclinical hypothyroidism is higher; iron deficiency is an independent risk factor for the development of the disease. 2, the impact of iron deficiency on the thyroid during pregnancy Iron is an important component of thyroid peroxidase (TPO), and TPO in the process of thyroid hormone synthesis is very critical, so the lack of iron can lead to TPO synthesis is limited, the reduction of thyroid hormones. Once you’ve been linked to a decrease in thyroid hormones, things don’t look good. “Cretinism” is because of congenital thyroid hormone reduction caused by stunted growth, not only stupid and short stature. 3, iron monitoring during pregnancy is indispensable At present, there is no routine monitoring of iron deficiency during pregnancy, on the one hand, economic reasons, and more importantly, has not attracted enough attention. Previous studies have shown that iron deficiency during pregnancy caused by hypothyroidism will affect fetal brain development, and the role is irreversible. Fetal development is actually the right time to do the right thing, after the critical period of neurodevelopment and then go to mend, sorry, it is too late. Therefore, it is necessary to conduct iron monitoring during pregnancy, not only to avoid anemia, but also to avoid affecting the baby’s development!