Ferric carboxymaltose for third-trimester refractory anemia and perinatal outcomes: Retrospective cohort analysis

Iron deficiency anemia (IDA) in the third trimester is associated with adverse perinatal outcomes, but data on intravenous ferric carboxymaltose (FCM) effects beyond hematologic response remain limited.

This retrospective cohort study, conducted at Mersin University Hospital (January 2019 - March 2024), included 311 pregnant women diagnosed with IDA in the third trimester who were clinically recommended FCM therapy due to inadequate response to oral ferrous sulfate. Among these, 206 accepted FCM treatment (in addition to continued oral iron) while 105 declined and received oral iron alone. Women were compared as two groups: those who received oral iron alone versus those who received oral iron plus a single-dose FCM in the third trimester,. At four timepoints (baseline, post-FCM, delivery, and postpartum), hemoglobin (Hgb), hematocrit, MCV, and MCHC levels were evaluated. The primary outcome was maternal perinatal hemoglobin response, while the secondary outcome was the investigation of its correlation with key neonatal outcomes following FCM administration. Repeated measures ANOVA, two-way ANOVA, and correlation analyses were used.

The FCM group showed significantly higher Hgb levels at baseline, delivery, and postpartum (all p < 0.05). Birth weight (3164 ± 564 g vs. 2952 ± 691 g, p = 0.007), umblical cord blood pH (7.34 ± 0.04 vs. 7.28 ± 0.03, p < 0.001), and Apgar scores were also improved in the FCM group. Neonatal intensive care unit (NICU) admission was significantly reduced (20.9 % vs. 31.4 %, p = 0.041), as was the incidence of fetal growth restriction (16.5 % vs. 38.1 %, p < 0.001). In the FCM group, changes in Hgb from post-FCM to postpartum were positively correlated with 1-minute Apgar scores (r = 0.177, p = 0.011). Neonates requiring NICU admission showed an attenuated rise in Hgb across the same interval (p = 0.041), and women with adverse composite outcomes had greater Hgb fluctuation, particularly from delivery to postpartum (p = 0.020).

Third-trimester FCM therapy leads to superior hematologic correction and improved neonatal outcomes compared to oral iron alone. Hemoglobin recovery patterns after FCM may be predictive of neonatal adaptation and adverse outcomes, highlighting the broader perinatal significance of timely parenteral iron therapy in late pregnancy.