Strengths and Limitations
The strengths of this study include the blinding of clinician, health care team, patient, and statistician, the long follow-up period, including longer-term assessment of child health. The findings can reassure obstetric teams of the safety, efficacy, and comprehensive benefits of IVI iron to treat ID and IDA in pregnancy.
The limitations include the variable number of participants who returned for each post infusion appointment. This is particularly relevant for the 4 weeks post infusion time point, where only around 50% of participants in each arm attended. To address this, we conducted a post-hoc sensitivity analysis assessing the number of participants receiving an infusion as a function of the total number of participants in each arm, assuming that patients who did not attend an appointment did not require an infusion. The results supported our non-equivalence findings. Although our trial was conducted at a single site, we observed changes in all blood markers of iron status over the study period biologically consistent with a difference in the ability of both doses to adequately restore iron status. This is important, given that even in this smaller sample, the two-fold difference in the need for a repeat infusion between the doses represents a significant addition to standard care, with associated costs and no differences in neonatal or child outcome.