During pregnancy, the immune system faces a particular challenge of protecting mother and vulnerable offspring. Mothers rely on nutrients to maintain their physiological condition and immune system, as well as to nourish developing young. A key question is: when mothers face challenges to their physiological state, how do they adjust energy allocation to protect themselves and their young? When does this result in adverse outcomes, such as pre-term birth? To date, most research on pregnancy and immunity involves longitudinal studies in humans or experiments on laboratory rodents. We have a solid understanding of how nutrition or inflammation in pregnancy influences birth timing, offspring physiology and behaviour. Surprisingly few studies have, however, considered the interaction between nutrition and inflammation. This project will aim to fill this gap by using a diverse toolkit: evolutionary models, experiments in insect models of pregnancy, and analyses of human cohort studies.