Offspring prematurity, family socioeconomic status, and parental investment: the bavarian longitudinal study

Abstract Evolutionary models of parental investment propose that parental investment may vary with child characteristics relevant to reproductive value, parental resources (i.e., socioeconomic status; SES), or their interaction. The relative importance of these factors in high-income societies remains unclear. Using preterm birth as a proxy of variation in early-life biological characteristics, we analyzed data from 607 preterm and 859 full-term children in the Bavarian Longitudinal Study. Participants were born between January 1985 and March 1986 in Bavaria, Germany, and comprised neonatal at-risk infants requiring admission to a children’s hospital within 10 days of birth and healthy term-born controls. Parental investment across seven domains was assessed during the first 9 years of life. Linear mixed models examined hypotheses derived from reproductive value-based allocation (H1), resource-based allocation (H2), and contingent parental investment models (H3). Results strongly supported H2: high-SES parents invested more than low-SES parents across most domains after accounting for prematurity. Prematurity was additively associated with lower parental investment in some domains, providing partial support for H1. No clear evidence supported the interaction predicted by H3. Overall, parental investment was more consistently associated with family SES than with prematurity, whereas associations with prematurity were more domain specific. These findings inform evolutionary models of parental investment while highlighting policy implications for reducing social inequities.