Association of Birthweight with Maternal Trajectories of Effort-Reward Imbalance and Demand-Control Across Pregnancy

Objectives: We assessed longitudinal patterns of effort-reward imbalance (ERI) and demand-control (DC) scores in pregnancy, and their association with newborn birthweight (BW). Methods: Sixty-one women were surveyed four times across pregnancy using the ERI and DC questionnaires. Trajectories of change in ERI and DC scores across pregnancy were constructed using growth mixture modeling, and their associations with BW were examined with generalized linear regression. Results: Declining ERI (diminishing effort with stable/increasing reward) was associated with higher BW (408 g; P = 0.015), and was robust to other work factors. DC trajectory was not significantly associated with BW. Conclusions: Declining ERI may reflect improved work psychosocial climate across pregnancy, or a conscious reduction in effort. The ERI model may represent more flexible work characteristics, whereas job control may be less amenable to short-term alteration. Surveys in more diverse pregnant working populations could be recommended.