Purpose To compare the efficacy of intravenous (IV) iron (ferric derisomaltose) with oral iron (ferrous fumarate) in women 14-21 weeks pregnant with persistent iron deficiency (ferritin

Methods In a single-centre, open-label, randomised controlled trial at a Danish hospital, women with persistent iron deficiency after routine oral iron treatment were allocated to receive 1000 mg IV iron (single-dose) or 100 mg elemental oral iron daily. Outcomes were assessed during an 18-week follow-up period. The primary endpoint was the proportion of nonanaemic (haemoglobin [Hb] >= 11 g/dL) women throughout follow-up. Other outcomes included changes in haematological parameters, patient-reported fatigue, and quality of life (QoL). Safety was assessed by recording adverse events.

Results From July 2017 to February 2020, 100 women were randomised to IV iron and 101 to oral iron. Throughout followup, 91% of women were non-anaemic in the IV iron group compared with 73% in the oral iron group (18% difference [95% confidence interval 0.10-0.25]; p < 0.001). The mean Hb increase was significantly greater with IV iron versus oral iron at Weeks 6 (0.4 versus - 0.2 g/dL; p < 0.001), 12 (0.5 versus 0.1 g/dL; p < 0.001), and 18 (0.8 versus 0.5 g/dL; p= 0.01). Improvements in fatigue and QoL were greater with IV iron versus oral iron at Weeks 3 and 6. The incidence of treatment-related adverse events was comparable between treatment groups.

Conclusion IV iron was superior in preventing anaemia compared with oral iron in pregnant women with persistent iron deficiency; biochemical superiority was accompanied by improved fatigue and QoL.