Results
cognitive developmentThe
REGRESSION
Selected maternal and offspring characteristics at 1y, 2y, and 6-7y for the study sample are presented in Table 
Sample characteristicsMean scores for each domain and overall cognitive and social-emotional development at 1y, 2y, and 6-7y are presented in Table 
Cognitive and social-emotional development, by child sex*p < 0.05; ** p < 0.01; *** p < 0.001The wealth gaps in cognitive and social-emotional development across these periods are shown in Fig. 
Inequality trends in child development, by wealth quintileFSIQ: Full-Scale Intelligence Quotient; Q: QuintileFigure 
Wealth disparities in cognitive developmentThe comparisons were between the first and the fifth quintiles. Step 1 was adjusted for maternal ethnicity, child age, and child sex. Other steps adjusted for the controlled variables in step 1 and types of preconception supplementation. Cognitive development at 6-7y models also adjusted for wealth residual at 6-7y. Maternal factors including education, IQ, and depressionStatistical significance from multivariable linear regression in each step comparing difference in outcomes between the lowest and highest wealth quintiles: * p < 0.05, ** p < 0.01, *** p < 0.001FSIQ: Full-Scale Intelligence Quotient; HAZ: Height-for-age-z-scores; SD: Standard deviationThe changes in wealth gaps in social-emotional development are shown in Fig. 
Wealth disparities in social-emotional developmentThe comparisons were between the first and the fifth quintiles. Step 1 was adjusted for maternal ethnicity, child age, and child sex. Other steps adjusted for the controlled variables in step 1 and types of preconception supplementation. Social emotion at 6-7y models adjusted for wealth residual at 6-7y. Maternal factors including education, IQ, and depressionStatistical significance from multivariable linear regression in each step comparing difference in outcomes between the lowest and highest wealth quintiles: * p < 0.05, ** p < 0.01, *** p < 0.001HAZ: height-for-age Z-score; SD: Standard deviation