Timing of Complementary Feeding and Infant Growth Trajectories in Prospective Cohort Studies: A Systematized Review and Analysis of Socioecological Variation.

Complementary feeding (CF) before 6 months of age is associated with both infant growth faltering and rapid growth. This disparity may reflect reverse causality and local norms. We conducted a systematized review of prospective studies examining infant growth and CF. We examined the potential for reverse causality and socioecological factors that appeared to influence feeding and growth outcomes. In 22 studies that met inclusion criteria, growth trajectories following earlier CF largely tracked prior growth. Earlier CF was generally associated with slower growth in lower resource populations, and more rapid growth in higher resource contexts. Local norms and caregivers' perceptions of growth were often discussed as factors impacting feeding decisions, but were not explicitly modeled. Future research may benefit from bioethnographic approaches that integrate contextual understanding of local dynamics to more comprehensively examine interactions between growth trajectories, caregiver perceptions, local norms, and health risks that influence CF timing and growth outcomes.