Exploring thematic dimensions of breast pumping discussions in an online community using large language models and multiple correspondence analysis.

Background: Breast pumping is a central part of infant feeding for many parents, yet professional guidance often gives limited attention to psychosocial and experiential aspects. Online communities offer valuable insight into how parents describe and navigate these experiences. Large language models provide new opportunities to analyze large volumes of online discussions. Objective: To identify and describe major thematic patterns in online discussions about breast pumping and infant feeding, with a focus on sensory concerns related to stored milk and their links to parental distress. Methods: Four subreddits related to pumping and breastfeeding were selected, and 107,447 relevant posts, extracted from November 2010 to December 2024, were retained in the analysis. Relevant content was identified using a combination of keyword matching and semantic similarity. Eleven binary-coded questions covering practical, experiential, and psychosocial topics were developed. Llama 3.1 8B was used for systematic classification. Ten questions achieving classification accuracy above 75% were retained. Multiple correspondence analysis was used to explore underlying thematic dimensions. A Supplementary keyword co-occurrence analysis examined discussions of sensory changes in stored milk. Results: Four main dimensions were identified, explaining 52.5% of total variance. Dimensions 1 (16.2%) and 2 (13.6%) differentiated discussions focused on feeding decisions and emotional experiences from those explicitly addressing sensory changes in expressed milk. Dimensions 3 (11.8%) and 4 (10.9%) distinguished concerns about perceived effects of pumping on milk quality from practical and work-related aspects of pumping. In Conclusion: These findings suggest gaps in current guidance on milk storage and quality and highlight the need for more targeted support and interventions for pumping parents. Although sensory changes in stored breastmilk were mentioned relatively infrequently, they emerged as a distinct theme in pumping-related discussions. The frequent co-occurrence of lipase concerns with frozen milk stashes reflects a recurring situation in which parents discover sensory changes only after substantial effort has been invested in building a stored milk supply.