Epigenetic Clocks as Biomarkers of Early-Life Development: State of the Field and Opportunities

The social world impacts maternal–fetal biology, influencing developmental trajectories and future health risk. Health and social programs aim to intervene in the first 1,000 days to promote optimal child outcomes. However, existing tools to evaluate perinatal programs are limited in their ability to project policy-relevant, longer-term child outcomes. DNA methylation-based epigenetic clock measures of biological aging are emerging as metrics to evaluate health-span impacts of interventions in adults. A set of epigenetic clocks has been developed specifically for infants and children, but their validity and interpretation remain uncertain. Evaluation of research on early-life clocks is needed to inform their application in developmental science. In this review, we synthesize studies examining associations between early-life clocks, prenatal exposures, and health and development in the first 1,000 days. Our findings highlight interpretive challenges around current early-life clocks and identify opportunities for the development of novel measurements that can advance the field.