Preconception vs First-Trimester Screening and Treatment for Iron Deficiency Anemia

Inclusion Criteria: * Women aged 18-45 years * Residence in a participating township * Intention to attempt natural conception within 6 months after enrollment * Ability to complete the required study procedures * Ability and willingness to provide written informed consent Exclusion Criteria: * 1.Non-iron deficiency anemia or other hematologic disorders: thalassemia, sickle cell anemia, anemia of chronic disease, and other hematologic conditions will be excluded based on complete blood count findings (including hemoglobin concentration) in combination with questionnaire assessment. Renal insufficiency (eGFR \<45 mL/min/1.73 m²) 2: hepatic insufficiency (ALT or AST \>3 times the upper limit of normal) 3: uncontrolled heart disease (New York Heart Association \[NYHA\] functional class III-IV) Acute or chronic infections, including HIV infection, active tuberculosis, and uncontrolled hepatitis B Multiple pregnancy 4: current pregnancy complicated by major fetal malformations or chromosomal abnormalities 5: history or current diagnosis of preeclampsia, placental abruption, or placenta previa History of hypersensitivity to intravenous iron therapy or iron overload disorders 6: receipt of blood transfusion or intravenous iron therapy within 1 month before enrollment Psychiatric disorders or cognitive impairment that would interfere with study participation or compliance with study procedures