Middlemiss, W., Granger, D., Goldberg, W., & Nathans, I. (2012). Asychrony of mother-infant hypothalamic-pituitary-adrenal axis activity following extinction of infant crying response induced during the transition to sleep. Early Human Development, 88(4), 227 - 232.
There is some work by Marc D. Lewis from the University of Toronto, early-mid 1990's on distress and IQ in infants and preschoolers. Some of it was published in Developmental Psychology I recall.