Objective: Iron deficiency is the most common nutritional deficiency in pregnancy and a key contributor to maternal anemia and postpartum transfusion. However, no consensus exists regarding optimal screening strategies or ferritin thresholds for early detection in non-anemic women. To evaluate whether first-trimester maternal ferritin levels predict postpartum blood transfusion in non-anemic pregnant women and to establish population-specific ferritin cut-off values for transfusion risk.
Materials and
Methods: This retrospective study included 386 singleton pregnancies followed and delivered at a tertiary university hospital between September 2022 and February 2024. Women with first-trimester hemoglobin (Hb) ≥11 g/dL were eligible. Patients with hemorrhage-related complications, hemoglobinopathies, or early iron therapy were excluded. Maternal demographic and laboratory parameters and neonatal outcomes were retrieved from electronic records. Receiver operating characteristic analyses were performed to determine optimal first-trimester thresholds for predicting postpartum transfusion.

Results: According to World Health Organization criteria (ferritin <15 μg/L), 29% of women were iron-deficient; using the 30 μg/L criterion, 66.6% showed depleted iron stores. Postpartum anemia occurred in 43%, and 8% required transfusion. Patients who required transfusion were significantly older and had higher parity (p=0.019 and <0.001, respectively). Median first-trimester ferritin was 22.65 μg/L. Optimal predictive threshold was 19.6 μg/L for ferritin (Area under the curve =0.634; p=0.012). In multivariable analysis, parity independently predicted transfusion (Odds ratio [OR]=1.85, p=0.001), while ferritin showed a borderline inverse association (OR=0.98, p=0.056). No significant association was observed between first-trimester ferritin and composite neonatal outcomes.

Conclusion: First-trimester ferritin <19 μg/L identifies women at increased risk of postpartum transfusion, even when Hb is normal. Routine ferritin screening in early pregnancy could enhance patient blood-management strategies by enabling timely detection and treatment of subclinical iron deficiency.