Outcomes of implementing the International Code of Marketing of Breast-milk Substitutes as national laws: a systematic review.

BACKGROUND: The International Code of Marketing of Breast-milk Substitutes, or 'the Code,' sets standards to regulate marketing of commercial milk formula (CMF) to protect breastfeeding. World Health Organization member states are advised to legislate the Code into national law, but understanding of its implementation outcomes is limited. This systematic review aimed to examine implementation outcomes in countries implementing the Code as national law. METHODS: We systematically searched five academic databases in September 2022 for articles published in English from 1982 to 2022. We double-screened titles/abstracts and then full texts for eligible articles reporting implementation outcomes of the Code in 144 eligible countries. We used the Mixed Methods Appraisal Tool for quality assessment and synthesized data thematically. We applied the Proctor et al. framework to guide synthesis of implementation outcomes, organizing our findings according to its taxonomy. RESULTS: We included 60 eligible articles of the 12,075 screened, spanning 28 countries. Fifty-seven articles focused on legal compliance, 5 on acceptability, and 1 on feasibility. Compliance was assessed across multiple sources, including mothers, health workers, media, points of sale, and product labels. Maternal exposure to CMF promotion remained widespread, with reports of mothers receiving free samples and coupons, and encountering media advertisements. Compliance of health workers varied across countries, with many reporting contact with CMF companies despite legal prohibitions. Public hospitals generally showed better adherence to the national law than private ones. While implementing the Code as national law effectively regulated the promotion of CMF for infants aged 0-12 months in public settings and in the media, it remains insufficient in addressing the promotion of unregulated products like growing-up milk, which are often marketed through emerging strategies such as cross-promotion and digital advertising. Point-of-sales compliance was inconsistent, with many countries reporting non-compliant price-related promotions. CONCLUSION: To enhance legal compliance, robust monitoring and reporting systems are necessary. Utilizing technology-assisted solutions for monitoring compliance can be an option for countries with limited human resources. Adequate training for health workers and communication strategies targeting shop managers about national law are also essential in enhancing their acceptability and compliance.