15, 58 and 59 Lactation has been associated with attenuated

stress responses, especially that of cortisol.8, 9, 10, 11 and 12 Attenuated cortisol stress responses,8, 9 and 10 as well as attenuated total cortisol and free cortisol stress responses,11 were observed in lactating mothers compared to the non-lactating. These results suggest that lactation attenuates neuro-endocrine responses to stress,8 selleck kinase inhibitor a factor that has been related with fewer postpartum depressive symptoms.60, 61 and 62 In a recent study on maternal adreno-corticotropic hormone (ACTH) and cortisol release patterns during a breastfeeding session, researchers found that breastfeeding was associated with a significant decrease in ACTH and cortisol levels.63 Skin-to-skin contact before sucking the breast was shown to play an important role in the reduction of these levels; the longer the duration of skin-to-skin contact, the lower

the maternal cortisol levels.63 Additionally, the usual diurnal pattern of cortisol, consisting of high morning levels and gradual decline throughout the day (also associated with fewer postpartum depressive symptoms),64 was found to be more common in multiparous breastfeeding women compared with the non-breastfeeding.12 Despite the fact that some studies did not report differences in daily cortisol levels in depressed pregnant or postpartum women,8, 65, 66 and 67 cortisol has also been found to be lower,10 as well as higher in depressed mothers when compared with their non-depressed counterparts.60 and 68 A recent study suggested that depressed mothers present a down regulated Erastin purchase HPA axis, showing lower salivary cortisol levels compared with non-depressed mothers.62 Conversely, another recent study found significantly higher levels of serum cortisol in the group of depressed mothers.69 A different diurnal pattern of cortisol, with higher cortisol levels at waking and no increase from waking to 30 minutes (compared to

a significant increase in cortisol levels from waking to 30 minutes found in non-depressed women), was reported in postpartum depressed women.64 These Protein kinase N1 data support the possibility that postpartum depression may be associated with a deregulated HPA axis. However, empirical evidence is equivocal, probably due to the presence of a variety of procedures (for example, diurnal pattern or daily cortisol levels in saliva, blood, or urine) to measure different HPA axis functions. Results suggest that breastfeeding might promote a tighter regulation of diurnal basal cortisol secretion,8, 9, 10, 11 and 12 and the stability of diurnal cortisol secretion lowers the risk of postpartum depression.64 However, most studies regarding postpartum depression do not control for breastfeeding, and most studies about breastfeeding do not control for depression.