Girls exposed to higher milk cortisol levels at three-months of age exhibited significantly less BMIP gains over the first 2 years of life compared to girls exposed to lower milk cortisol levels. By 24 months of age, infants, regardless of sex, exposed to higher levels of milk cortisol had lower BMIPs than infants exposed to lower levels of milk cortisol. For graphing purposes, high and low cortisol levels were estimated for milk cortisol levels at one standard deviation above and below the mean, respectively. The model estimates are adjusted for maternal weight gain in pregnancy and the time of day of the milk cortisol collection. Infant age was modeled as a continuous variable (in months).