Effectiveness of antepartum intravenous iron sucrose: dose timing and impact on outcomes.

Objective: Studies have demonstrated that antepartum intravenous iron sucrose infusion (IVFe) is safe and improves predelivery hemoglobin (Hb). Yet, there is little data guiding timing of administration or number of doses required to be impactful. We sought to determine if timing of antepartum IVFe and number of doses provided impacts efficacy.

Methods: We performed a retrospective cohort study of women who obtained prenatal care and delivered at our institution 10/1/2015-10/30/2017. Women with a third-trimester hemoglobin (Hb) < 9.5 g/dL were included. Women with hemoglobinopathies and those who received an antepartum blood transfusion were excluded. Women receiving ≥1 antepartum 300 mg IVFe dose were considered in the IVFe group.

Results: Five-hundred-twenty-three (6.1%) of 8563 delivering women were included. Sixty-five (12.4%) of included women received IVFe. By timing of IVFe, the earlier IVFe was received before delivery, the greater the median Hb increase (No IVFe: Δ0.8g/dL, IVFe 0-1 weeks predelivery: Δ0.05 g/dL, 1-2 weeks: Δ0.9 g/dL, 2-4 weeks: Δ1.5 g/dL, 4-6 weeks: Δ1.8 g/dL, 6-8 weeks: Δ1.8 g/dL, 8-12 weeks: Δ2.75 g/dL,  = .0001). When comparing each stratum to the No IVFe group, only those receiving IVFe >2 weeks before delivery had a significant increase in Hb level from third trimester to delivery. By the number of IVFe doses, increasing administrations incrementally impacted Hb difference from third trimester to delivery, with only those receiving at least 3 doses demonstrating statistically significant Hb change compared to the No IVFe group.

Conclusion: Antepartum IVFe effectively increases Hb from the third trimester to delivery admission when administered 2-12 weeks predelivery. There is increasing benefit the further out the IVFe is administered and with an increasing number of doses. Initiatives to combat antepartum anemia should focus on early detection and treatment to best optimize outcomes.