The objective was to evaluate the effects of suckling within 30 min after birth when skin-to-skin body contact for mothers and infants was held constant in both cases (n = 32) and control groups (n = 25). Mother-infant interaction during breast-feeding, infants' time spent in nursery and different aspects of breast-feeding were evaluated. Prolactin and gastrin were measured in maternal serum before and after breast-feeding on day 4 post partum. The aim to evaluate effects of early post delivery suckling failed since only six of the 32 case infants did suck at this time. In spite of this, we found three significant differences among cases and controls. In the case group where all infants had touched or licked the areola and nipple, the mothers left the infants in the nursery for a significantly shorter time and significantly more mothers talked to their infants during the short breast-feeding observation. Median gastrin levels were significantly lower in cases than in controls both before (P less than 0.01) and after (P less than 0.03) breast-feeding. In conclusion, the infant's early touch of the mother's areola and nipple seemed to have positively influenced the mother/infant relationship during the first four days after birth. It was also associated with lower maternal gastrin levels which suggests that maternal neuroendocrine functions were also influenced. Ten months after birth, we found no differences between cases and controls.