The rates and factors of perceived insufficient milk supply: A systematic review

Perceived insufficient milk supply (PIMS) is one of the major reasons for discontinued breastfeeding. We aimed to estimate the rates and evaluate related factors of PIMS. We searched four databases for relevant articles published from January 2000 to March 2021. We then performed a meta-analysis of the pooled data to estimate the rates and related factors of PIMS using Stata 15.0. Descriptive analyses of textual data were performed to summarise the related factors of PIMS if data could not be synthesised quantitatively. The quality of included studies was assessed using Newcastle-Ottawa scale (NOS), AHRQ checklist or Consolidated Criteria for Reporting Qualitative Research (COREQ). Overall, 27 studies were included in this review. At different periods after delivery, approximately 50% of mothers reported PIMS as the reason for stopping breastfeeding, while for breastfeeding mothers, the incidence of PIMS ranged from 10% to 25%. Breastfeeding initiation (OR 4.22, 95%CI 1.57-11.34) and breastfeeding knowledge (OR 7.10, 95%CI 2.00-25.26) were two factors influencing PIMS. Besides, PIMS had a strong negative relationship with breastfeeding self-efficacy (r = -0.57); moderate negative association with infant suck ability (r = -0.46) and planned breastfeeding duration (r = -0.45); and a moderate positive correlation with formula supplementation (r = 0.42). Descriptive analyses revealed that infant crying was reported to be a sign of PIMS, and inadequate intake of energy/liquids was a reported cause of it. This review identified a high proportion of women reporting PIMS, particularly among those who stopped breastfeeding. Deliberate interventions were needed to improve breastfeeding for mothers at risk.