Bibian van der Voorn

87 MILK GLUCOCORTICOID DIURNAL RHYTHMICITY newborn. This has also been suggested for other chronobiotic signaling factors in human milk, such as melatonin, which might guide the development of a sleep-wake rhythm in infants 37 . In conclusion, in mothers who gave birth to a very preterm infant, breast-milk glucocorticoid concentrations were lower. In addition, we showed that they follow a diurnal rhythm, highly correlated to the circadian rhythm of HPA axis activity. Little is known about the effect this has on the developing newborn, so future studies are needed to elucidate this.