Dear Chanita, my understanding is that baby drinks amniotic fluid and digests it, solids go into bowel and build up into what we call meconium. The meconium is loaded with bilirubin. After birth the "normal" mechanism is for baby to drink colostrum and poop out bili laden meconium. Colostrum has laxative effect for just this purpose. "Commonly" access to breast is limited, colostrum is limited, less laxative, less pooping. Then baby begins to reabsorb bilirubin through the gut wall. Bilirubin gets to immature liver, which dumps it back into the blood stream, baby's bili begins to go up, baby nurses less, and the whole thing spirals downward. All because baby did not get liberal doses of colostrum, early and often! This is an oversimplification of physiology, but basically what happens. Can you tell I loved KA's explanation of normal vs common? Sincerely, Pat in SNJ