Randomisation and masking
Using a sealed envelope containing an allocation code that was computer-generated by an independent statistician not otherwise involved in the trial, women were randomly assigned in a 1:1 ratio with random permuted blocks of size 4 or 6, stratified by site to receive standard of care or ferric carboxymaltose. The trial was not blinded as it was judged unfeasible to provide placebo infusions in this setting. However, laboratory and delivery room staff (who collected efficacy outcomes) were masked to allocation.