Since 2009, the Healthy Start Study has followed over 1,000 ethnically diverse women to assess the impact of intrauterine exposures on neonatal outcomes. Healthy Start 1 began in 2010 with a cohort of 1,410 pregnant women who were planning on delivering at University of Colorado Hospital in the United States. Healthy Start 2 refers to the follow-up of the same children as they began turning 4, 5, and 6 years old. Then, in 2016, the National Institutes of Health (NIH) awarded the study with the Environmental Influences on Child Health Outcomes, or the ECHO grant, to continue follow-up with Healthy Start mothers and children between the ages of 8 years and 12 years. Women were invited to participate in four in-person research visits: two visits during pregnancy, a third visit shortly after delivery, and a fourth visit when the child was approximately 5 months old. Denver ECHO and Colorado ECHO are waves of funding of the Healthy Start cohort.