Child stunting starts in utero: Growth trajectories and determinants in Ugandan infants

Childhood stunting remains a public health burden worldwide. Although many studies have examined early life and in-utero risk factors; most have been observational and have used analytic techniques that make inferences limited to population means, thereby obscuring important within-group variations. This study addressed that important gap. Using data from a birth cohort of Ugandan infants (n = 4528), we applied group-based trajectory modelling to assess diverse patterns of growth among children from birth to 1-year old. A multinomial regression model was conducted to understand the relationship between risk factors and observed patterns across groups. We found that the onset of stunting occurred before birth and followed four distinct growth patterns: chronically stunted (Group 1), recovery (Group 2), borderline stunted (Group 3) and normal (Group 4). The average length-for-age z-score (LAZ) at birth was -2.6, -3.9, -0.6 and 0.5 for Groups 1-4, respectively. Although both Groups 1 and 2 were stunted at birth, stunting persisted in Group 1 while children in Group 2 recovered by the fourth month. Group 3 exhibited mild stunting while Group 4 was normal. Wasting and underweight were observed in all groups, with the highest prevalence of underweight in Group 1. Wasting gradually increased among children born already stunted (Groups 1 and 2). This showed the importance of distinguishing children by their growth patterns rather than aggregating them and only comparing population averages against global growth standards. The design of nutrition interventions should consider the differential factors and potential for growth gains relative to different risks within each group.