MAIN BODY: We argue that broader consideration of lactation, incorporating evolutionary, comparative and anthropological aspects, could provide new insights into breastfeeding practices and problems, enhance research and ultimately help to develop novel approaches to improve initiation and maintenance. Our current focus on breastfeeding as a strategy to improve health outcomes must engage with the evolution of lactation as a flexible trait under selective pressure to maximise reproductive fitness. Poor understanding of the dynamic nature of breastfeeding may partly explain why some women are unwilling or unable to follow recommendations.
CONCLUSIONS: We identify three key implications for health professionals, researchers and policymakers. Firstly, breastfeeding is an adaptive process during which, as in other mammals, variability allows adaptation to ecological circumstances and reflects mothers' phenotypic variability. Since these factors vary within and between humans, the likelihood that a 'one size fits all' approach will be appropriate for all mother-infant dyads is counterintuitive; flexibility is expected. From an anthropological perspective, lactation is a period of tension between mother and offspring due to genetic 'conflicts of interest'. This may underlie common breastfeeding 'problems' including perceived milk insufficiency and problematic infant crying. Understanding this - and adopting a more flexible, individualised approach - may allow a more creative approach to solving these problems. Incorporating evolutionary concepts may enhance research investigating mother-infant signalling during breastfeeding; where possible, studies should be experimental to allow identification of causal effects and mechanisms. Finally, the importance of learned behaviour, social and cultural aspects of primate (especially human) lactation may partly explain why, in cultures where breastfeeding has lost cultural primacy, promotion starting in pregnancy may be ineffective. In such settings, educating children and young adults may be important to raise awareness and provide learning opportunities that may be essential in our species, as in other primates.
MATERIALS AND METHODS: A systematic search of observational studies conducted in ASEAN countries between 1 January 2010 and 31 December 2020 was performed in the Medline, PubMed and Google Scholar databases. The quality of studies was evaluated based on The Joanna Briggs Institute Checklist. The analysis was performed with Review Manager software version 5.4. Metaanalysis of the estimates from primary studies was conducted by adjusting for possible publication bias and heterogeneity.
RESULTS: Twenty-five studies including 19924 postnatal mothers were included in this review. The pooled prevalence of PPD is 22.32% (95% CI: 18.48, 26.17). Thailand has the highest prevalence of PPD with a pooled prevalence of 74.1% (95% CI: 64.79, 83.41). The prevalence of PPD was highest when the assessment for PPD was conducted up to 6 weeks postpartum with a pooled prevalence of 25.24% (95% CI: 14.08, 36.41). The identified determinants of PPD were unplanned pregnancy, term pregnancy, lack of family support and physical violence. There were limited studies done and high heterogeneity in terms of quality, methodology, culture, screening method and time of PPD measurement.
CONCLUSIONS: Approximately one in five postpartum women in ASEAN countries had PPD. The risk factor that lowers the risk of PPD is unplanned and term pregnancies, while women with a lack of family support and experienced physical violence increase the risk of PPD. Robust prevalence studies are needed to assess the magnitude of this problem in ASEAN countries.
METHODS: This cross-sectional study was conducted on 100 women who had breastfed another child in Selangor. Data were obtained using a validated questionnaire (Cronbach alpha = 0.8) and processed using the SPSS software.
RESULTS: Results showed 43.0% of respondents had at least breastfed one someone else's child. Meanwhile, there were 3.0% of the respondents were nursing seven to ten other children. A total of 237 children have been breastfed by the respondents (n = 100). Of these, 21.5% children were breastfed less than five times, while 78.5% children were breastfed less than five times. Most mothers recorded their milk child background data, and this shows that the community is aware of the importance of data documentation and it indirectly proves that the authorities should act on these current needs.
CONCLUSIONS: This study shows that there is a wet nursing practice in the society. Obviously, a phenomenon, trend and practice in the society has the ground and basis as to why it existed and is upheld. Researches related to wet nursing and matters connected to it should continue so as to bring about much good to society.