O061 Maternal Circadian Disruption from Shift Work and the Impact on the timing of Melatonin in their Breast Milk

Abstract Introduction Infants are not born with a circadian rhythm. Research shows that breast milk clearly exhibits a 24-hour pattern, with melatonin concentrations high during the evening and night but barely detectable in daytime milk. The presence and timing of melatonin in breast milk suggests that this hormone may help provide sleep timing information to infants, thereby supporting the development of their own circadian cycle. Currently, it is not known if disturbances of maternal circadian rhythm, such as shift work, impact the circadian rhythmicity of breastmilk. The aim of this study was to investigate whether maternal circadian disruption, from working night shift has an impact on melatonin timing in breastmilk. Methods A prospective repeated measures study design was undertaken to compare melatonin levels in breastmilk across shift types (day shift/non-workdays and night shifts). Four 10ml breastmilk samples were collected by participants the same time of the day, across five consecutive days. Results. A total of 11 mothers completed the study. Analysis is still ongoing but preliminary results show a potential difference in breastmilk melatonin between pre-night shift, night shift and post night shift, indicating a change in the circadian timing of the breastmilk. Discussion The findings from this study suggest that there is a potential effect from maternal circadian disruption from shift work on breast milk melatonin. This is an important first step in exploring the impact of maternal circadian misalignment disorders on breastmilk hormones and provides preliminary evidence that future research is needed in this area.