(302) Perinatal outcomes following intravenous iron therapy among those with iron deficiency anemia in pregnancy

Repeated cross-sectional analysis of individuals aged 13-50 years with pregnancy and delivery data at > 20 weeks’ gestation available in the MarketScan Commercial Insurance Research Database from 2011-2021. Those with IDA, identified by International Classification of Diseases insurance claims codes, were included. We could not control for IDA severity in this dataset. The exposure was receiving IV iron, identified by National Drug Codes. Maternal and neonatal outcomes included severe maternal morbidity, postpartum hemorrhage, postpartum depression, need for blood transfusion, neonatal IDA and NICU admission. Baseline characteristics were compared between those receiving and not receiving IV iron therapy in pregnancy or through 6 weeks postpartum. Multivariable logistic regression models estimated the association between IV iron therapy and maternal and neonatal outcomes. A Cox proportional hazard model estimated the association between IV iron therapy and neonatal IDA.

Results:
Of 110,719 pregnancies complicated by IDA, 7,911 (7.15%) received IV iron therapy. Those receiving IV iron were older and were more likely to have maternal co-morbid health condition (Table 1). IV iron therapy was associated with higher odds of postpartum depression (5.55% vs 3.77 %, aOR 1.50, 95% CI 1.36-1.66), postpartum hemorrhage (4.68% vs 3.74%, aOR 1.25, 95% CI 1.12-1.40) and severe maternal morbidity (5.47% vs 4.80%, aOR 1.14, 95% CI 1.03–1.26) with no difference in maternal blood transfusion. IV iron therapy was associated with increased risk of neonatal IDA (59.0% vs 41.1 %, HR 1.78, 95% CI 1.73-1.83).

Conclusion:
Among those with maternal IDA, IV iron therapy was associated with higher risk of some adverse maternal and neonatal complications. Findings may reflect residual confounding with more severe anemia in those receiving IV iron therapy, which could not be evaluated or controlled for in this dataset. Further research is needed to optimize management of maternal IDA.