To understand the epidemiological characteristics of anemia and iron deficiency in pregnancy and describe the epidemiological situation of anemia and iron deficiency.~To explore the influence factors of anemia and iron deficiency in pregnancy.~To explore the influence of anemia and iron deficiency during pregnancy on the pregnancy outcome of mothers and infants.
The purpose of this study is to describe the prevalence of anemia and iron deficiency in pregnancy through a multi-center, prospective follow-up study . To explore the influence factors of anemia and iron deficiency in pregnancy; to explore the influence of anemia and iron deficiency in pregnancy on maternal and fetal outcomes.