Background Maternal undernutrition and micronutrient deficiencies remain highly prevalent in Bangladesh and contribute to maternal anaemia, low birth weight, preterm birth, and adverse neonatal outcomes. Although iron-folic acid supplementation (IFAS) is routinely provided through antenatal care services, it does not address the full spectrum of micronutrient deficiencies. Multiple micronutrient supplementation (MMS) has demonstrated superior outcomes in clinical trials; however, evidence from real-world programmatic settings in Bangladesh is limited.

Methods and analysis This experimental study will be conducted from March 2025 to March 2026 through antenatal care platforms coordinated by the Institute of Public Health Nutrition (IPHN), with centralised laboratory analysis at the National Institute of Neurosciences & Hospital (NINS&H), Dhaka. Pregnant women will receive either MMS or IFAS according to routine service delivery. The primary outcome is infant birth weight. Secondary outcomes include maternal haemoglobin and micronutrient biomarkers, preterm birth, dietary diversity, and supplementation adherence. Quantitative data will be analysed using multivariable regression models in SPSS with adjustments for confounders and geographic clustering. A concurrent process evaluation will assess implementation, fidelity and acceptability.

Ethics and dissemination Ethical approval has been obtained from the Institutional Review Board of NINS&H. Written informed consent will be obtained from all participants. Study findings will be disseminated through peer-reviewed publications, policy briefs, and stakeholder engagement workshops.

Introduction Maternal undernutrition and micronutrient deficiencies remain major public health challenges globally, particularly in low- and middle-income countries such as Bangladesh. Inadequate intake of essential vitamins and minerals during pregnancy contributes substantially to adverse maternal and neonatal outcomes, including anaemia, low birth weight, preterm births, stillbirths, impaired foetal growth, and long-term developmental consequences for children. Pregnancy is a period of increased physiological demand that requires a higher intake of iron, folate, vitamin B12, vitamin D, iodine, zinc, and vitamin A to support placental development, erythropoiesis, immune regulation, and foetal organogenesis. Failure to meet these requirements compromises both maternal health and foetal development, increasing risks that extend beyond the perinatal period.

In Bangladesh, micronutrient deficiencies persist despite notable improvements in antenatal care coverage and maternal health indicators. National surveys and programme reports consistently demonstrate a high prevalence of anaemia, inadequate dietary diversity, and insufficient micronutrient intake among women of reproductive age, particularly in low-income and food-insecure households. Socioeconomic inequality, limited access to diverse diets, early marriage, and high fertility further exacerbate nutritional vulnerability during pregnancy. Poor maternal nutritional status is associated with obstetric complications, maternal morbidity, and adverse birth outcomes, while inadequate foetal nutrient supply has been linked to impaired neurodevelopment, weakened immune function, increased susceptibility to childhood illness, and faltering growth.

Since 2001, the Government of Bangladesh has implemented routine iron-folic acid supplementation as part of antenatal care services to reduce maternal anaemia and prevent neural tube defects. While IFAS has contributed to improvements in iron status, its impact on broader pregnancy outcomes has been modest. IFAS addresses only two micronutrients and does not account for the multiple concurrent deficiencies commonly observed among pregnant women in low-resource settings. As a result, many women are deficient in other essential micronutrients that play a critical role in foetal growth and development.

Multiple micronutrient supplementation, particularly the United Nations International Multiple Micronutrient Antenatal Preparation (UNIMMAP) formulation, was developed to address these gaps by providing a balanced combination of 15 essential vitamins and minerals. Accumulating evidence from randomised controlled trials and systematic reviews indicates that MMS provides superior benefits compared with IFAS alone. A Cochrane review reported significant reductions in low birth weight, small-for-gestational-age births, and maternal anaemia among women receiving MMS. An individual participant data meta-analysis of 17 trials further demonstrated reductions in stillbirth and neonatal mortality associated with MMS supplementation, particularly among populations with high baseline nutritional deficiency.

Beyond immediate birth outcomes, adequate maternal micronutrient intake during pregnancy has important implications for long-term child health and development. Improved intrauterine nutrition supports optimal foetal growth trajectories, neurocognitive development, immune system maturation, and metabolic programming. Evidence suggests that MMS supplementation enhances foetal nutrition and may reduce the risk of early-life micronutrient deficiencies, which are strongly associated with childhood stunting, impaired cognitive development, and decreased educational attainment. These long-term benefits point out the necessity of optimising antenatal nutrition interventions as part of broader strategies to break intergenerational cycles of undernourishment.

Recognising this growing body of evidence, the World Health Organization and UNICEF have updated their antenatal nutrition recommendations and added MMS to the WHO Essential Medicines List for pregnant women in populations with high micronutrient deficiency burdens. Several countries in South Asia and sub-Saharan Africa have initiated national or pilot MMS programmes to replace or complement IFAS. However, concerns regarding cost, supply chain complexity, adherence, and programme feasibility have restricted widespread adoption in some settings. As a result, policymakers increasingly emphasise the necessity of country-specific implementation evidence to inform scale-up decisions.

In Bangladesh, the National Nutrition Services established a Technical Advisory Group to guide MMS implementation and generate locally relevant evidence to support policy development. Pilot community-based nutrition initiatives coordinated by the Institute for Public Health Nutrition and partner organisations have demonstrated improvements in maternal nutrition knowledge, dietary practices, and antenatal service utilisation. However, these initiatives have not systematically compared MMS and IFAS under routine service delivery conditions using robust outcome measures. There are still gaps in the evidence about how well MMS works in the real world, how well people follow it, and how easy it is to use in current antenatal care platforms.

This protocol describes a quasi-experimental evaluation comparing MMS and IFAS among pregnant women receiving antenatal care services coordinated by IPHN, with centralised laboratory analysis conducted at the National Institute of Neurosciences & Hospital, Dhaka. Participants will be tracked from enrolment to delivery between March 2025 and March 2026. This study seeks to produce extensive, policy-relevant evidence by amalgamating biochemical, anthropometric, dietary, and geographic data to guide national antenatal nutrition programming and facilitate evidence-based decision-making in Bangladesh.

Hypotheses

Null hypothesis (H0):

There is no statistically significant difference in maternal nutritional status and birth outcomes between pregnant women receiving multiple micronutrient supplements and those receiving iron-folic acid supplements.

Alternative hypothesis (H1):

Pregnant women receiving multiple micronutrient supplements will demonstrate significantly improved maternal nutritional status and better birth outcomes compared with those receiving iron-folic acid supplements

Study objectives General Objective

• The general objective of the study is to assess the impact of multiple micronutrient supplementation, in comparison to iron-folic acid supplementation, on the nutritional status and birth outcomes of pregnant women in Bangladesh.

Specific objectives

1. To compare infant birth weight between MMS and IFAS recipients

2. To assess changes in maternal hemoglobin and selected micronutrient biomarkers

3. To evaluate differences in preterm birth and other pregnancy outcomes

4. To assess dietary diversity and household food insecurity during pregnancy

5. To examine supplementation adherence and implementation feasibility within routine antenatal care platforms

   Methodology Study design This study will be designed as an experimental evaluation comparing multiple micronutrient supplementation (MMS) with standard iron-folic acid supplementation (IFAS) delivered through routine antenatal care platforms in Bangladesh. A randomised controlled trial design was not feasible due to programmatic constraints and ethical considerations, as supplementation is delivered according to existing service delivery mechanisms rather than individual random allocations. Instead, this design allows for prospective follow-up by pregnant women exposed to either MMS or IFAS under real-world conditions.

   Participants will be enrolled during early pregnancy and followed longitudinally through delivery. Quantitative components will assess differences in maternal nutritional biomarkers and birth outcomes, while qualitative components will explore implementation fidelity, acceptability, and operational feasibility. This pragmatic approach aligns with BMJ Open guidance for evaluating public health interventions embedded within health systems and allows for policy-relevant evidence generation.

   Study site and sampling frame (please mention the name of UHCs) The study will be conducted within selected antenatal care service areas supported by the Institute of Public Health Nutrition under the Ministry of Health and Family Welfare, Bangladesh. These sites include urban and peri-urban antenatal clinics serving diverse socioeconomic populations. The selection of study sites reflects geographic variation in service delivery capacity, population density, and maternal nutritional vulnerability, allowing for evaluation of supplementation effectiveness across different programmatic contexts.

   The sampling frame comprises pregnant women attending routine antenatal care services within the selected IPHN-supported catchment areas. Geographic clustering will be defined at the upazila level to facilitate program implementation and enable the spatial analysis of service coverage. All eligible pregnant women presenting to participating antenatal clinics during the recruitment period (10 days) will be screened for eligibility. A centralised laboratory analysis of biological specimens will be conducted at the National Institute of Neurosciences & Hospital (NINS&H), Dhaka, which serves as the designated reference laboratory and ethical oversight institution for the study.

   Intervention description Participants in the intervention arm will receive daily multiple micronutrient supplementation using the UNIMMAP formulation, which contains 15 essential vitamins and minerals, including iron, folic acid, vitamin A, vitamin D, vitamin E, vitamin C, vitamin B-complex, iodine, zinc, selenium, and copper. The formulation is designed to meet the increased nutritional requirements of pregnancy and address multiple concurrent micronutrient deficiencies common in low-resource settings.

   MMS will be distributed through routine antenatal care visits in accordance with national programmatic guidelines. Participants will be instructed to consume one tablet daily throughout pregnancy. Monthly follow-up visits will be conducted to replenish supplements, assess adherence, monitor adverse events, and provide nutrition counseling. Counseling will emphasize the importance of consistent supplementation, dietary diversity, and timely antenatal care attendance. Program delivery will be integrated within existing IPHN service platforms to reflect real-world implementation conditions.

   Control description Participants in the control arm will receive standard iron-folic acid supplementation as part of routine antenatal care services. IFAS consists of a daily tablet containing 60 mg elemental iron and 400 μg folic acid, in line with national antenatal care guidelines. Distribution, counseling, and follow-up procedures for the control group will mirror those of the intervention arm to the extent possible, ensuring comparability between groups while reflecting standard program practice.

   Intervention Allocation The intervention group of the study population will be applied the UNIMAPS with the prescribed amount according to the WHO protocol. UNIMAPS contains 15 essentials micronutrients which are Iron (30 mg), folic acid (400 mcg), vitamin A (800 mcg), vitamin C (70 mg), vitamin D (5 mcg), vitamin E (10 mg), vitamin B1 (1.4 mg), vitamin B2 (1.4 mg), vitamin B3 (18 mg), vitamin B6 (1.9 mg), vitamin B12 (2.6 mcg), iodine (150 mcg), zinc (15 mcg), selenium (65 mcg) and copper (2 mg). On the other hand, the control group will be advised the IFAS (Iron 60 mg, Folic acid 400 mcg) according to the routine government prescribed amount.

   Pregnant women screening and recruitment Pregnant women attending routine antenatal care visits at participating clinics will be screened for eligibility by trained health workers. Screening will include confirmation of pregnancy status, assessment of gestational age, and review of medical history. Eligible women will receive detailed information about the study, and written informed consent will be obtained prior to enrollment. Recruitment will continue throughout the study period until the target sample size is reached. Participants will be followed prospectively through delivery.

   Timing of Blood Sample Collection

   Blood samples will be collected at two time points:

   • Baseline (T0): Before initiation of MMS or IFAS supplementation during first trimester of enrollment.
   • Endline (T1): After completion of 180 tablets of MMS or IFAS or during late third trimester.

   This longitudinal sampling will allow within-group and between-group comparison of biomarker changes.

   Pre-collection Preparation and Informed Consent

   • Written informed consent will be obtained separately for blood collection, in addition to study participation consent.

   • Participants will be informed about:

     • Purpose of blood testing
     • Volume of blood drawn
     • Potential risks and benefits
     • Confidentiality and right to withdraw

   • Participants will be advised to attend the sample collection point in a fasting state (8-10 hours) where feasible for metabolic markers (FBS, HbA1c).

   Blood Collection Procedure Sample Collection Personnel Blood samples will be collected by trained phlebotomists or certified laboratory technicians following standard biosafety protocols.

   Volume and Types of Samples

   Approximately 8-10 mL of venous blood will be collected from each participant using sterile techniques:

   Test Category Tube Type Volume Hemoglobin, CBC EDTA tube 2 mL Serum micronutrients (iron, folate, vitamin B12, ± vitamin D) Serum separator tube (SST) 4-5 mL FBS and HbA1c Fluoride/EDTA tube 2-3 mL

   Sample Handling and Transportation

   • Blood samples will be labeled with unique participant identification codes without personal identifiers.
   • Serum samples will be centrifuged within 2 hours of collection at field laboratories or nearby health facilities.
   • Serum aliquots will be stored in cryovials at -20°C or lower until transport.
   • Samples will be transported to the central reference laboratory using cold chain logistics (ice packs and insulated boxes) within 24-48 hours.

   Laboratory Analysis

   Biochemical analyses will be conducted in accredited laboratories following standardized protocols:

   • Hemoglobin: Automated hematology analyzer
   • Serum iron and ferritin: Chemiluminescent immunoassay (CLIA) or ELISA
   • Serum folate and vitamin B12: Electrochemiluminescence immunoassay
   • Vitamin D (if budget permits): LC-MS/MS or CLIA
   • FBS: Enzymatic colorimetric method
   • HbA1c: High-performance liquid chromatography (HPLC) Internal and external quality control procedures will be maintained.

   Data Linkage and Confidentiality

   • Laboratory results will be linked to participant records using unique study IDs in the KoBo database.
   • Personal identifiers will be stored separately in encrypted files accessible only to the principal investigator.
   • Results indicating severe anemia or critical micronutrient deficiency will be communicated to participants and referred to local health facilities.

   Quality Assurance and Monitoring

   • Standard Operating Procedures (SOPs) will be developed for phlebotomy, sample processing, storage, and transport.
   • Periodic supervision and random audits will be conducted by the research team.
   • Duplicate samples (5-10%) will be tested for laboratory reliability.
   • Data consistency checks will be performed before statistical analysis.

   Statistical Analysis Plan for Biomarkers

   • Baseline comparability between MMS and IFAS groups will be assessed using t-tests or Mann-Whitney U tests.
   • Within-group pre-post changes will be assessed using paired t-tests or mixed-effects models.
   • Multivariable regression models will adjust for socio-demographic and pregnancy-related confounders.
   • Difference-in-differences analysis will estimate the impact of MMS compared to IFAS.

   Data collection Data will be collected using a combination of quantitative surveys, anthropometric measurements, laboratory assessments, and geographic information system (GIS) tools. Structured questionnaires will be administered at enrollment and during follow-up visits to capture sociodemographic characteristics, obstetric history, dietary diversity, household food insecurity, antenatal care utilization, and supplementation adherence. Questionnaires are adapted from validated instruments, including the Household Food Insecurity Access Scale (HFIAS) and the Minimum Dietary Diversity for Women (MDD-W).

   Anthropometric measurements, including maternal weight, height, and mid-upper arm circumference, will be collected at enrollment using standardized equipment and procedures. Venous blood samples will be collected by trained phlebotomists for assessment of hemoglobin and selected micronutrient biomarkers. Samples will be transported under cold-chain conditions to the National Institute of Neurosciences & Hospital for analysis following standard laboratory protocols.

   GIS coordinates of participating antenatal clinics and participant residence clusters will be recorded to enable spatial analysis of service coverage and outcome distribution. All data will be collected electronically using Kobo Collect to minimize data entry errors and enable real-time monitoring.

   Follow up and Outcome Measures The follow up of the pregnant women will be on the ANC visits. Research assistant will visit the pregnant women on every month to her home to get the information about the compliance of the supplements. The blood sample will be collected two times for biochemical tests.

   Outcome evaluation (methods) Birth outcomes will be assessed using standardized procedures. Infant birth weight will be measured within 24 hours of delivery using calibrated digital scales. Gestational age will be determined based on last menstrual period and confirmed through antenatal records where available. Maternal nutritional status will be assessed through laboratory analysis of hemoglobin and selected micronutrient biomarkers using venous blood samples collected by trained phlebotomists. Laboratory analyses will follow standardized protocols at NINS&H to ensure quality and consistency.

   Process evaluation (methods) Process evaluation will assess the fidelity, reach, dose, and acceptability of MMS and IFAS delivery within routine antenatal care services. Quantitative process indicators will include supplement distribution records, attendance at follow-up visits, and self-reported adherence. Qualitative data will be collected through semi-structured interviews with health workers, supervisors, and program managers to explore implementation experiences, barriers, and facilitators.

   Data collection for the process evaluation will occur concurrently with outcome evaluation to allow triangulation of findings. Interview guides will focus on supply chain management, counseling practices, workload implications, and perceptions of MMS compared with IFAS. Findings will inform interpretation of outcome results and provide actionable recommendations for program improvement.

   Study outcomes The primary study outcome is infant birth weight measured in grams within 24 hours of delivery. Secondary outcomes include maternal hemoglobin concentration, selected micronutrient biomarker levels, gestational age at delivery, preterm birth, dietary diversity score, household food insecurity status, and supplementation adherence. Process indicators such as coverage, fidelity, and acceptability will be assessed as part of the process evaluation. Outcome selection aligns with WHO antenatal nutrition indicators and national monitoring priorities.

   Quantitative survey The quantitative survey will collect information on sociodemographic characteristics, reproductive history, dietary intake, household food security, and antenatal care utilization. Dietary diversity will be assessed using a 24-hour recall based on the MDD-W checklist. Household food insecurity will be measured using HFIAS-based questions. Surveys will be administered by trained interviewers in the local language using electronic data capture.

   Qualitative interviews Qualitative interviews will be conducted with a purposive sample of pregnant women, health workers, and program supervisors. Interviews will explore perceptions of supplementation, adherence challenges, counseling quality, and acceptability of MMS compared with IFAS. Interviews will be audio-recorded with consent, transcribed verbatim, and translated into English for analysis.

   Field procedure and quality control Field activities will be guided by detailed standard operating procedures covering participant recruitment, data collection, specimen handling, and follow-up. Data collectors and health workers will receive comprehensive training prior to study initiation and refresher training during implementation. Supervisors will conduct routine field monitoring, observe interviews, and review data for completeness and accuracy. Laboratory quality control procedures will include calibration of equipment, use of control samples, and periodic external quality assurance

   Data quality management Data quality will be ensured through automated validation checks within the electronic data capture system, daily review of incoming data, and periodic data audits. Discrepancies and missing data will be flagged and resolved promptly through field verification where feasible. A secure, password-protected database will store all study data.

   Data analysis

   Quantitative data analysis Quantitative data will be analyzed using IBM SPSS Statistics. Descriptive statistics will summarize baseline characteristics. Multivariable linear regression will be used to compare mean birth weight and continuous biomarker outcomes between groups, while logistic regression will be applied for binary outcomes such as low birth weight and preterm birth. Models will adjust for predefined confounders, including maternal age, parity, baseline nutritional status, dietary diversity, and antenatal care utilization. Geographic clustering will be accounted for using cluster-adjusted standard errors. Detailed statistical procedures and variable coding are provided in Supplementary File 4.

   Qualitative data analysis Qualitative data will be analyzed using a thematic framework approach. Transcripts will be coded independently by two researchers to identify key themes related to implementation fidelity, acceptability, and feasibility. Discrepancies will be resolved through discussion, and findings will be triangulated with quantitative results to enhance interpretation.

   Patient and public involvement Community representatives were consulted during protocol development to ensure cultural appropriateness.

   Ethics and dissemination Ethical approval for this study has been obtained from the Institutional Review Board of the National Institute of Neurosciences & Hospital (NINS&H), Dhaka. All study procedures will be conducted in accordance with the principles of the Declaration of Helsinki and relevant national ethical guidelines. Written informed consent will be obtained from all participants prior to enrollment. For participants with limited literacy, the consent form will be read aloud, and consent will be documented using a thumbprint in the presence of an impartial witness.

   Participant confidentiality will be strictly maintained throughout the study. Unique identification numbers will be used in place of personal identifiers, and all electronic data will be stored on password-protected servers with access restricted to authorized study personnel only. Biological specimens will be handled and stored according to institutional biosafety protocols.

   Study findings will be disseminated through peer-reviewed journal publications, national and international scientific conferences, policy briefs, and stakeholder dissemination workshops. Results will be shared with relevant government bodies, including the Ministry of Health and Family Welfare, to inform antenatal nutrition policy and program implementation.

   Study status The protocol has received ethical approval, and preparatory activities including staff training, tool finalization, and procurement of study materials are underway. Participant recruitment is scheduled to begin in March 2025 and will continue until the target sample size is achieved. Follow-up will continue through delivery, with study completion anticipated by March 2026.

Inclusion Criteria:

• Participants will be eligible if they meet all of the following:

  1. Confirmed pregnancy, preferably in the first trimester, with singleton pregnancy where feasible.
  2. Permanent residence within the selected study catchment areas and ability to remain in the study area throughout follow-up.
  3. Enrollment in IPHN-supported antenatal care or supplementation programs.
  4. Nutritional vulnerability identified through screening indicators (eg, MUAC, BMI, or hemoglobin).
  5. Willingness to receive MMS or IFAS supplementation as assigned by routine service delivery platforms.
  6. Provision of written informed consent (thumbprint with witness for illiterate participants).
  7. Planned facility-based delivery or verifiable delivery location.

Exclusion Criteria:

• Participants will be excluded if any of the following apply:

  1. Withdrawal of informed consent at any stage.
  2. Diagnosed chronic medical conditions likely to influence pregnancy outcomes or nutritional biomarkers (eg, diabetes, hypertension, thyroid disorders, thalassemia).
  3. Planned relocation outside the study area before completion of follow-up.
  4. High-risk pregnancy requiring specialized tertiary care at enrollment.
  5. Participation in another nutrition intervention or clinical trial during the study period.
  6. Multiple gestation pregnancies (eg, twins).

This study will recruit only pregnant women who attend routine antenatal care visits. So eligibility to participate in the study according to their biological sex is limited by their gender identity

Individual participant data (IPD) will not be shared because the dataset contains sensitive personal and clinical information that could compromise participant confidentiality. Furthermore, there is no specific plan or ethical approval in place for secondary data sharing beyond the current study objectives. Only aggregated, de-identified results will be disseminated through publications and presentations.

Blinding The study will be an open-label clinical trial where neither the pregnant women nor the research assistant will be blinded to the allocation of the UNIMAPS and IFS. After the computer-generated simple random sampling technique, the amount will be given by the research assistant with the prescribed amount.