The prolactin response to suckling.

Changes in prolactin concentration during single suckling episodes in twenty breast-feeding women from four to 40 weeks post partum have been investigated. Basal prolactin concentration and the increase in prolactin secretion in response to single suckling episodes and amount of milk taken by the infant were both independent of time post partum until the introduction of supplementary feeds, when a significant decrease with time was apparent. Basal concentrations of prolactin were dependent upon the interval between suckling episodes, and the magnitude of the prolactin response varied with the time of day when suckling took place. The relationship between acute suckling episodes and the long term pattern of prolactin secretion over time post partum is discussed.