Introduction: Chronic stress is long term stress, generally lasting weeks to months to years. The concept of chronic stress is based on how frequently the stressors appear over period of time. Chronic & severe stressful events may alter hormonal balance & lead eventually to failure of homeostasis. Chronic stress response leads to pregnenolone steal, which causes production of huge amount of Cortisol (the principal stress hormone). So, serum cortisol level can be considered as an objective measure of chronic stress. Excessive Cortisol levels during pregnancy has been associated with adverse pregnancy outcomes. Keeping in view of this, present study was conducted to assess effect of chronic stress on the pattern of milk output in women of reproductive age. Materials and methods: A longitudinal cohort study was conducted in pregnant women in the reproductive age between 21 and 45 years. Holmes and Rahe stress scale was used to measure stress. In our study we have included anthropometric parameters (Height, Weight, BMI), physiological parameters (BP, HR) and hormonal assay (for cortisol, prolactin). Volunteers were screened in 1st, 2nd and 3rd trimesters as well as during postpartum upto 7days. Milk volumes were measured for 7 days by baby test weighing method. Results: We observed that mean cortisol levels in 1st trimester were 14.15±1.91, 20.44±1.33, 23.10±2.53 µg/dl in mild, moderate and severely stressed women respectively. The levels were in increasing order in 2nd, 3rd trimester and postpartum. Mean prolactin levels were in decreasing order in women with mild to severe stress. It was found that in moderately and severely stressed women, prolactin levels were in decreasing order from 1st day to 5th day postpartum when compared with mildly stressed women. It was observed that mildly stressed women produced ˜ 700ml of milk per day, moderately stressed women produced ˜ 425 ml/day and severely stressed women produced ˜ 360 ml/day. Milk volumes were reduced by ˜ 40% in moderately stressed women and ˜ 50% in severely stressed women when compared with milk volumes of mildly stressed women. Conclusion: Serum Cortisol levels of moderate and severely stressed women were significantly raised in comparison with mildly stressed women. Cortisol levels were high after delivery also. This indicates chronically stressed women remain in the same stressed state even in the postpartal period. In our study, serum prolactin levels were decreased in moderate as well as in severely stressed groups when compared with mildly stressed group, and has shown its effect on milk volume. Decreased milk volume in moderate and severely stressed women indicates that cumulative effects of changing life events and daily hassles with failure of coping reflex leads to chronic stress which causes decreased lactation.

Keywords: Chronic stress; Cortisol; Milk volume; Prolactin.