Prenatal and postnatal droughts interact in shaping cognitive development

Developmental plasticity refers to biological adaptations, most often prenatally, to environmental cues. These can help organisms adapt to similar postnatal environments, with health benefits if prenatal and postnatal conditions match. While associations between various prenatal exposures and adverse offspring health have been documented, the interaction between prenatal and postnatal conditions remains less understood. We address this gap by examining whether pre- and postnatal drought exposures interact in their impact on cognitive performance, as early-life nutrition is a critical factor for cognitive development.

Standardized math and reading scores from 11-16 year-olds in rural India (N = 2,032,917) from the 2007-2018 Annual Status of Education Report (a cross-sectional cognitive assessment household survey) were combined with University of Delaware Terrestrial Precipitation data. Given the high reliance on rainfed agriculture in the setting, rainfall levels below the 20th percentile of the district-specific long-term mean served as a proxy for nutritional adversities in a quasi-experimental study setup.

We show that early-life droughts adversely impact cognitive function. We find positive interaction terms between prenatal and postnatal drought exposures, suggesting that children already exposed to droughts prenatally are better equipped for postnatal droughts.

The findings of this study align with the predictions around phenotypic plasticity, i.e., that prenatal conditions prepare organisms for similar postnatal challenges. However, given the increasing unpredictability of the climate, such alignments cannot be planned or anticipated, implying frequent mismatches between prenatal and postnatal conditions.