Abstract: The promotion of breastfeeding intention and extension of breastfeeding duration are the current problems which should be addressed in the field of mother-infant in China. Despite the benefits of breast-milk and being willing to breastfeed, the vast majority of mothers feel powerless in the actual feeding process. Psycho-social factors are the key factors that make them feel powerless about breastfeeding. So far, psycho-social factors have been found to play a significant role in breastfeeding behavior.
The Theory of Planned Behavior (TPB) is often used to discuss the relationship between psycho-social factors and breastfeeding behavior. The classic TPB breastfeeding model is still insufficient in predicting as most previous studies have only examined the influence of one or some of these factors on breastfeeding behavior. The extended breastfeeding TPB model has the potential to improve the effectiveness of TPB constructs to understand breastfeeding behavior. Nevertheless, there remains a lack of in-depth discussion and analysis in theory. Empirical studies on the psycho-social factors that influence breastfeeding behavior, based on the TPB, have been reviewed. According to the behavioral characteristics of breastfeeding, psycho-social factors such as affective attitudes, instrumental attitudes, subjective norms, perceived behavioral control, self-efficacy, moral norms, breastfeeding knowledge, and self-identity that are based on TPB of breastfeeding can effectively explain the breastfeeding intention and duration of mothers.
Regarding the attitudes towards breastfeeding, affective attitudes are significantly more effective than instrumental attitudes in explaining breastfeeding intentions, while instrumental attitudes are ineffective in predicting the duration of breastfeeding. As for the breastfeeding subjective norms, the norms inherited from elderly women in the family and hospital midwives can make difference to the intention of breastfeeding. In spite of this, only the norms inherited from elderly women in the family can play a significant role in predicting the duration of breastfeeding. While perceived behavioral control of breastfeeding can predict breastfeeding intention, its predictive role for breastfeeding duration varies across studies. The self-efficacy of breastfeeding exerts a significant positive effect on the intention and duration of breastfeeding, which supports new mothers in overcoming the difficulties when feeding their children. Breastfeeding moral norms, knowledge, and self-identification can all explain mothers' breastfeeding intentions and duration. These factors are even more predictive than attitudes as reported by some previous studies.
Future research should improve the theoretical model of breastfeeding TPB and conduct more localized prediction and intervention studies of breastfeeding. First, it is still not clear whether each influencing factor plays a unique role in the extended TPB model, or whether there is any association between these influencing factors. Thus, the integration and verification of the extended TPB model of breastfeeding is an important direction of further research. Second, “powdered milk”, “the relationship between mother-in-law and daughter-in-law”, “Generations nurturing” and other breastfeeding-related subjects in the context of Chinese culture shall be included in the research on breastfeeding TPB. Last, in the future intervention study, both doctors and midwives are supposed to enhance the positive effect of the intervention with breastfeeding by increasing their efforts to promote self-interested belief and active choice.

Key words: breastfeeding, the theory of planned behavior, psycho-social factors

摘要： 如何提升母乳喂养意向、延长母乳喂养持续时间,是当前我国母婴领域中广受讨论且亟需解决的问题。本研究着眼于影响母乳喂养行为的心理社会因素,综述了以往基于计划行为理论的相关成果。依据母乳喂养行为的特征,计划行为理论模型中的情感性态度、工具性态度、主观规范、知觉行为控制（包括自我效能感）、道德规范、哺乳知识和自我认同等心理社会因素能够有效地解释婴儿母亲的母乳喂养意向及持续时间。未来研究应进一步完善母乳喂养行为的计划行为理论模型,并以此为基础进行本土化的母乳喂养行为实证与干预研究。

关键词: 母乳喂养行为, 计划行为理论, 心理社会因素