Do parenting, reproductive and health traits cluster together in distinct trajectories? Evidence from two UK cohort studies

Life-history theory researchers often assume reproductive, parenting and health behaviours pattern across a fast–slow continuum, with ‘fast’ life histories (typified by short lifespans, early maturation and investing in quantity over quality of children) favoured in poor quality environments and/or when resources are scarce. These ideas, with different theoretical motivations, are echoed in the ‘diverging destinies’ and ‘weathering’ frameworks developed in the social sciences. Using latent class analysis on data from the UK’s Millennium Cohort and Born in Bradford Studies, we explored whether reproductive, parenting and health traits clustered into predicted ‘fast’ and ‘slow’ trajectories. We found that parenting and reproductive traits clustered together reasonably well, but health traits did not cluster with other domains as predicted. Furthermore, whilst age at first birth is often used to distinguish ‘fast’ and ‘slow’ trajectories, our analysis showed breastfeeding was a particularly important discriminating feature: women on ‘fast’ trajectories had lower rates of breastfeeding. Indicators of socioeconomic disadvantage and poor environmental quality generally predicted ‘fast’ life histories, with some exceptions. Our data further allowed us to test whether patterns differed between White British/UK-born and Pakistani-origin women: clustering was less pronounced amongst Pakistani-origin mothers and their trajectories were less well predicted by socioeconomic and environmental characteristics. Results provide limited support for the hypothesis that a range of reproductive, parenting and health traits cluster together, and that socioeconomic disadvantage and poor environmental quality predict ‘faster’ trajectories. This clustering is not always clear-cut; further, cultural factors are important in determining exactly how these trajectories play out.