Trajectory of Iron Indices in Moderately Anemic Pregnant Women Receiving Daily Iron–Folic Acid Supplementation: A Prospective Cohort Study

Background/Objectives: To study the trajectories of hematologic and biochemical markers in moderately anemic pregnant women receiving oral iron supplementation throughout pregnancy. Methods: This prospective cohort study was conducted from August 2021 to September 2023 involving 315 pregnant women from rural areas of Belgaum, Karnataka, India, with hemoglobin levels between 7.0-9.9 g/dL and serum ferritin <30 ng/mL and/or TSAT<20%. Participants received Iron-Folic Acid supplementation (IFAS) as per Anaemia Mukt Bharat guidelines. Blood samples were collected to measure various hematologic and iron markers and compared across each visits. Results: We report a complete adherence rate of 95.3% for iron and 97.8% for folic acid supplementation throughout pregnancy and also observed significant improvements in hemoglobin (9.36(8.55, 9.74) to 12.03(11.49, 12.72)) g/dL, hematocrit (29.93 ± 2.87 to 33.71 ± 3.69) %, MCV (72.16 ± 7.90 to 83.47 ± 7.65) fL, MCH (22.44 ± 3.01 to 26.77 ± 3.08) pg, levels from the early second to the early third trimester of pregnancy with significant difference (<0.001). Increased erythropoiesis was reported by a higher reticulocyte hemoglobin (23.30 ± 3.03 to 27.84 ± 3.83) pg and immature reticulocyte fractions (6.90(4.30, 9.50) to 7.30(4.3, 11.0)) %. Initially, iron, ferritin and TSAT levels increased but later stabilized or slightly declined towards the end of pregnancy. Conclusions: Daily IFAS in moderately anemic pregnant women improved the trajectory of iron indices, with peak gains in early third trimester. High adherence via counselling supports targeted monitoring and trimester-specific strategies to reduce maternal anaemia and may improve outcomes.