This study investigates the safety and efficacy of ferric derisomaltose (FDI) and its effect on blood transfusion requirements in women with severe anaemia secondary to heavy menstrual bleeding (HMB). Methods: Medical records of women aged ≥18 years who were admitted to Tuen Mun Hospital with severe iron deficiency anaemia (a haemoglobin level of <8.0 g/dL and a mean corpuscular volume of <80 fL) secondary to HMB in the periods before (1 July 2014 to 30 June 2018) and after (1 July 2018 to 30 June 2022) the introduction of FDI were retrospectively reviewed. Results: In total, 1373 and 983 patients were admitted before and after the introduction of FDI, respectively. The mean number of blood units transfused per patient decreased from the pre-FDI period to the post-FDI period (2.02 vs 1.19, p<0.001). The decrease remained significant after adjusting for age, ethnicity, baseline haemoglobin, and leiomyoma. In 384 patients who received FDI, 55 (14.3%) had a hypersensitivity reaction (HSR), 41 of which were mild. There were no cases of cardiac or respiratory arrest or allergic reaction necessitating adrenaline administration. The occurrence of an HSR was not associated with the number of known drug allergies (p=0.076), ethnicity (p=0.563), or age (p=0.06). After FDI administration, the mean haemoglobin level increased from 6.2 g/dL to 10.6 g/dL (p<0.001), whereas the mean ferritin increased from 22.5 μg/L to 149 μg/L (p<0.001) at 3 to 4 weeks. Conclusion: Intravenous FDI is safe and effective for treating severe iron deficiency anaemia secondary to HMB. FDI significantly reduces the requirement for blood transfusions. 14.3% of patients had an HSR. FDI mitigates the burden on blood transfusion services and supports patient blood management principles.