The relationship between antenatal food insecurity, fetal and postnatal growth: findings from the South African National Income Dynamics Study

Background Food insecurity during pregnancy has been associated with adverse child health outcomes including low birthweight and stunting. There are few studies that have examined the relationships between food insecurity and child health outcomes in low and middle income countries. This study aims to fill the gap by examining the relationship between food insecurity, low birthweight and stunting in children using a longitudinal sample of South African women and their children. Methods The primary exposure is a multidimensional, composite measure of household food insecurity that comprises three dimensions and six indicators. The primary outcome is a dichotomous measure of child LBW (≤ 2500 g) The secondary outcome is childhood stunting (height for age ≤2SD of the median) and severe stunting (height for age ≤3SD of the median) in the first five years of life. We used both unadjusted and adjusted regression models. Source data for the analysis came from the population-based, longitudinal data collected for wave one and three of the National Income Dynamics Study (2008 and 2012). Results Birthweight data were available for 1381 children and stunting data were available for 1444 children. The prevalence of LBW in the sample was 13.64%. The prevalence of stunting and severe stunting was 16.46% and 11.87%. The composite measure was not associated with low birthweight but was associated with underweight maternal BMI, a risk factor for low birthweight. Household dietary diversity, food expenditure below the Stats SA poverty line and the composite measure was associated with stunting and severe stunting in bivariate analyses. The measure was associated with severe stunting in the final model. Conclusions The finding that household food insecurity is associated with severe stunting for children in the first five years of life highlights the importance of adequate food and nutrition for vulnerable children in South Africa. Future studies can elucidate the relationship between antenatal food insecurity, low birthweight and other child outcomes. Policy interventions that focus on early childhood growth through alleviating food insecurity and addressing other drivers of malnutrition such as improving maternal education and dietary diversity can break the cycle of poor growth outcomes.