Iron-folic acid (IFA) supplementation in pregnancy is recommended by the WHO, with a dose of 60 mg of iron in contexts where anaemia remains a severe public health problem. Iron-containing supplements may cause side effects that affect acceptability and adherence in a dose-response manner. Maternal multiple micronutrient supplements (MMS), which include iron and folic acid plus additional micronutrients, are also recommended in the context of rigorous research, and programmes are considering transitioning from IFA to MMS containing 30 mg of iron. We will evaluate the effect of iron dose in MMS on maternal acceptability, side effects, adherence and preferences.

The Multiple Micronutrient Supplementation (MMS) Iron Dose Acceptability Crossover Trial is an individually randomised, quadruple-blind, non-inferiority crossover trial of daily antenatal MMS supplementation formulations that contain 60 mg, 45 mg and 30 mg elemental iron among pregnant women in Dar es Salaam, Tanzania. A total of 156 pregnant participants will be randomised to a sequence in which they receive each of the three MMS formulations for 1 month. Participants, investigators, outcome assessors and data analysts will be blinded to the treatment sequence. The primary trial outcome is participant-reported acceptability of each MMS formulation, measured on a Likert scale. Secondary and tertiary outcomes include preferred and least preferred formulation, identification of MMS formulation, reported side effects and adherence assessed by pill count. Regression analyses will be used to assess differences between formulations and will account for sequence and period effects of the crossover trial design. Qualitative in-depth interviews from a subsample of participants will be conducted to understand women’s perceptions and experiences taking the different MMS formulations.

The trial protocol was approved by Harvard T. H. Chan School of Public Health Institutional Review Board (IRB), the Ifakara Health Institute IRB, the Muhimbili University of Health and Allied Sciences IRB, the National Health Research Ethics Sub-Committee and the Tanzania Medicine and Medical Device Authority. Results will be shared through publications and presentations at the local, regional and international levels.

ClinicalTrials.gov Identifier: NCT06069869.