Introduction: Breastfeeding provides substantial health benefits for mothers and infants; however, exclusive breastfeeding rates remain below recommended levels in many settings.Social support from family members, peers,and healthcare providers plays a critical role in promoting successful breastfeeding.Given the increasing use of breastfeeding support instruments in research and practice,understanding the methodological quality of studies reporting these instruments is important.This review aimed to critically appraise the methodological quality of studies related to breastfeeding support instruments.

Methods:A systematic critical appraisal review was conducted following a structured literature search in PubMed, Scopus, ScienceDirect, Cochrane Library, SID,and Magiran for studies published in English or Persian up to September 2025.Four reviewers independently screened records and selected eligible studies. Methodological quality was assessed using the Mixed Methods Appraisal Tool (MMAT,2018).Data extraction was performed independently and discrepancies were resolved through consensus.

Results:Of 62 full-text articles assessed for eligibility,18 studies met the inclusion criteria, including 16 quantitative and 2 qualitative studies. Among quantitative studies, most demonstrated appropriate sampling strategies(87.5%), appropriate measurements (100%), and suitable statistical analyses(100%). However, only 18.75% of studies used representative samples of the target population, and several studies provided insufficient information regarding nonresponse bias.The two qualitative studies met all MMAT quality criteria.

Conclusion:The included studies generally demonstrated strong methodological quality in measurement procedures and analytical approaches. Nevertheless,important limitations were identified in sample representativeness and reporting practices, which may affect the generalizability of findings.Future research should prioritize rigorous sampling methods, transparent reporting, and appropriate management of missing data to strengthen the evidence base related to breastfeeding support instruments.