Allocation concealment
An independent study statistician generated the randomisation codes. Medication bottles are labelled by an independent clinical pharmacist from Royal Darwin Hospital. Labels incorporate a clear specification for mother or infant to avoid mix-up. Sequentially labelled mother and infant bottle pairs are stored in strata-specific boxes at room temperature in a secure facility. Active and placebo study medicine bottles and administration syringes are identical. Liquid medicines are indistinguishable in appearance and taste.