[unseennude]

The parents of this 3-day-old baby arrive in the emergency department stating that the newborn has been acting well since being discharged from the hospital yesterday. She is breastfeeding every 2-3 hours, moving her bowels multiple times daily, wetting her diapers after each feeding, and consoling appropriately.



However, the parents report that, when they placed the baby on her side earlier today, she turned different colors?the side down was red, and the side up was white. On examination, the baby appears normal, but when laid on her right side, her skin changes colors, as demonstrated in the photograph.

What is this phenomenon called? What causes the color change to occur?
Hint:This is a benign condition of neonates.