Association of Early Feeding Practices with Gastrointestinal Symptoms in Infants During the First 12 Months: A Multicenter Prospective Cohort Study

Background: Functional gastrointestinal disorders (FGIDs) are highly prevalent among infants. Exclusive breastfeeding has been consistently associated with better gastrointestinal health. However, current evidence regarding the associations between early feeding practices and infant gastrointestinal development remains limited. Objectives: To examine the associations between early feeding practices at 1 month of age and gastrointestinal symptoms and overall gastrointestinal burden in infants during the first 12 months of life. Methods: In this multicenter prospective cohort study, 669 healthy mother–infant pairs were finally included. According to feeding practices at 1 month of age, infants were categorized into three groups: exclusive direct breastfeeding (EDB, n = 236, 35.28%), bottle-fed expressed breastmilk (EBB, n = 150, 22.42%), and mixed feeding (MF, n = 283, 42.30%). Gastrointestinal (GI) symptoms were assessed using the Infant Gastrointestinal Symptom Questionnaire (IGSQ) and symptom items from the PedsQL™ Infant Scales. Generalized estimating equations (GEEs) were used to assess the associations. Results: Infants in the EDB group had the lowest incidence of GI symptoms and lower IGSQ scores throughout the follow-up period. Compared with EDB, the MF group showed higher IGSQ scores (β = 0.95, p = 0.002) and higher odds of constipation (OR = 1.64, p < 0.001), vomiting (OR = 1.70, p < 0.001), and swallowing difficulty (OR = 1.79, p = 0.002); these associations remained robust across multiple sensitivity analyses. The EBB group showed higher odds of certain symptoms in the main analysis, but sensitivity analyses (e.g., time-varying exposure) indicated that these associations were not robust, except for bloating (OR = 1.31, p = 0.042). Conclusions: The EDB is the optimal strategy for infant gastrointestinal health and should be prioritized. The MF is robustly associated with increased odds of constipation, vomiting, swallowing difficulty, and overall gastrointestinal burden. The EBB may slightly increase the odds of bloating, which can be mitigated by paced feeding and adequate burping.