Introduction

Iron requirement by the fetus is high in the third trimester and in case the iron deficiency anemia (IDA) is not addressed adequately, it may lead to serious perinatal outcomes. The American College of Obstetricians and Gynecologists (ACOG) recommend oral iron supplementation as the first-line treatment for IDA during pregnancy and states that intravenous (IV) iron may be considered in women who are unresponsive or diagnosed with severe iron deficiency in the later stages of gestation. Oral iron supplements are associated with adverse effects affecting patient adherence and there is data which supports the use of IV iron in women with persistent iron deficiency despite oral supplementation. The data on maternal and neonatal outcomes with IV ferric carboxymaltose (FCM) along with oral iron therapy in the third trimester is limited.

Aim

To evaluate the perinatal complications beyond the hematologic efficacy of IV FCM along with oral iron therapy in the third trimester of pregnancy.

Method

Study Design

•   Retrospective cohort study

Treatment Strategy

• A total of 311 pregnant women diagnosed with IDA defined as Hgb <11g/dl and serum ferritin <30 µg/L were included
• The women were prescribed oral ferrous sulfate 200 mg/day from 12^th week of gestation upto delivery
• Women with inadequate hematological response were offered IV FCM at a dose of 1000 mg, upto a maximum of 20 mg/kg body weight
• A single-dose IV FCM in the third trimester was accepted by 206 along with the oral iron therapy, whereas 105 declined and received oral iron alone
• The outcomes were assessed at baseline, post-FCM, delivery, and postpartum

Endpoints

Primary Endpoints

• Hemoglobin (Hgb) levels
• Hematocrit (Hct)
• Mean corpuscular volume (MCV)
• Mean corpuscular Hgb concentration (MCHC)

  Secondary Endpoints

• Correlation between Hgb changes and maternal-fetal outcomes following FCM administration

Results

• FCM was administered at a median gestational age of 30 weeks
• Baseline serum ferritin levels were significantly lower in the FCM group; p<0.001
• The levels of Hgb, Hct, MCV, MCHC were significantly higher at baseline, delivery, and postpartum (all p < 0.05) in the FCM group
• The FCM group exhibited improvements in birth weight (3164 ± 564 g vs. 2952 ± 691 g, p = 0.007), umbilical cord blood pH (7.34 ± 0.04 vs. 7.28 ± 0.03, p < 0.001), and Apgar scores
• The rate of neonatal intensive care unit (NICU) admission and fetal growth restriction (FGR) was also lower in the FCM group as seen in Figure 1; p = 0.041 and p < 0.001 respectively

   

  Figure 1. Incidence of NICU admission and FGR

  

   

• A positive correlation was noted between postpartum changes in Hgb with 1-minute Apgar scores in the FCM group (p = 0.011), post administration of FCM
• Among neonates requiring NICU admission, change in Hgb from post-FCM to delivery was substantially lower as compared to those who did not require NICU admission (p = 0.041)
• Among neonates with composite adverse outcomes, the increase in Hgb level was greater from baseline to post-FCM and from post-FCM to delivery
• The fluctuation in Hgb was greater among women with adverse composite outcomes, particularly from delivery to postpartum (p = 0.020)

Conclusion

• Intravenous administration of ferric carboxymaltose in the third trimester of pregnancy along with oral iron therapy in moderate-to-severe IDA reduces adverse pregnancy outcomes, improves neonatal measures, and shows hemoglobin response patterns correlate with neonatal morbidity, highlighting importance of an overall effective iron correction significantly.

Eur J Obstet Gynecol Reprod Biol. 2026 Feb; 317. Doi: 10.1016/j.ejogrb.2025.114887.