Results: The increased duration of combined fuss/cry at term associated with lower psychomotor developmental index (PDI), [regression coefficient (b) = -0.83, p = 0.025]. Crying at term associated negatively with mental developmental index (MDI) (b = -0.91, p = 0.040) and PDI (b = -1.10, p = 0.015). The associations between fuss/cry and PDI, and crying and PDI persisted in multiple regression analysis (b = -0.89, p = 0.030 and b = -1.23, p = 0.018, respectively). Excessive fuss/cry (>= 180 min/day) at term associated with lower PDI (p = 0.005) and at 6 weeks with lower MDI (p = 0.024) and PDI (p = 0.012). Increase in the frequency of fuss/cry bouts at 5 months associated with higher PDI in both simple (b = 2.90, p = 0.045) and in multiple regression analysis (b = 3.60, p = 0.019).