Isotopic values of prenatal development: [delta][sup](13)C and [delta][sup](15)N variation in early-formed human tissues

Carbon (δ13C) and nitrogen (δ15N) isotope analysis illuminates diet and physiology in the past, yet interpretation is complicated by development and tissue-specific collagen formation. This study tests whether systematic isotopic offsets occur between auditory ossicles, deciduous dentin, long bones, and ribs in individuals who died as perinate, neonate, or young infants, and assesses implications for reconstructing maternal diet and early-life physiology. Materials and Methods Collagen δ13C and δ15N were measured for 106 samples from 27 individuals recovered from five sites spanning the Early/Late Iron Age, Early Roman, and 17th–19th centuries. Results Results reveal a consistent δ15N trajectory: values generally increase from ossicles to teeth and decrease from teeth to long bone/rib. Tooth–long bone/rib δ15N offsets are significant across the sample and within each age group. δ13C shows a modest, systematic increase from ossicle to tooth