This study followed a sample of 217 new mothers in a North Carolina county as they returned to work full-time, measuring their mental and physical health-related quality of life through 16 months postpartum. In general, working mothers of infants had mental health scores that were comparable to the general population of U.S. women, and physical health that was slightly better than women in general. Using ANCOVA and controlling for important demographic characteristics, health-related quality of life was compared between mothers experiencing low and high levels of economic hardship. Across the study period, women with high economic hardship, who constituted 30.7% of the sample, had levels of mental and physical health below those of women with low economic hardship. Mothers with high economic hardship also had less stable health trajectories than mothers with low economic hardship. The findings highlight the importance of reconsidering the traditionally accepted postpartum recovery period of six weeks and extending benefits, such as paid maternity and sick leave, as well as stable yet flexible work schedules.