Stern JE, et al. - Whether differences in birth outcomes among assisted reproductive technology (ART)-treated, subfertile, and fertile women exist in primiparous women with, singleton, vaginal deliveries was determined in this analysis. Between July 2004 and December 2010, Society for Assisted Reproductive Technology Clinic Outcome Reporting System (SART CORS) data were linked to Massachusetts vital records and hospital discharges for deliveries. Among singleton vaginal deliveries, greater odds of prematurity and low birthweight in ART-treated and subfertile, and perinatal death in subfertile deliveries were evident. Results of this study suggested that even low-risk pregnancies to ART-treated and subfertile women be managed for adverse outcomes.