Background: Babies have an excess of red blood cells over what they will need after they are born because they are extracting oxygen from the mother's blood, where the concentration is much lower than in air. In the days after they are born, they get rid of the excess, a destruction process that occurs in the liver and produces a yellow byproduct called "bilirubin." Because their livers are immature, the bilirubin tends to build up in the bloodstream instead of being passed through into the bile and from there into the intestines for disposal. (Sidenote: Colostrum, what the baby gets before the milk comes in, is a mild laxative that helps this along.)

I haven't looked at this review, but Lisa has hit the nail on the head. The near universal practice of early cord clamping for the past decades has created what Amy Romano and I are calling in the new edition of Obstetric Myths Versus Research Realities, an "iatrogenic" norm. "Iatrogenic" means "caused by doctors" as in "iatrogenic harm." It's like the way it used to be with the newborn weight gain charts. The old ones were based on infants who were formula fed and started on solids within a couple of months of birth. The growth rates of breastfed babies were compared with the formula fed babies, and their moms would be told that their baby's rate of weight gain was inadequate, and they should supplement. (Now they have separate charts for breastfed babies.) In this case, what is considered the "normal" range for bilirubin level is actually lower than what it would be were third stage were allowed to proceed physiologically, and babies got their full blood supply.

As for requiring phototherapy, years ago I was at a conference where a doctor spoke on this issue. He explained that doctors recognized that they were seeing neurologic harm in babies whose bilirubin counts exceeded 30 (Sidenote: that number is not an absolute; the more preterm the baby, the lower the threshold), so the thought was, "We never want to let bilirubin counts get that high, so we had better start treating at 20." After awhile, 20 felt like the threshold, and doctors started treatment at 15. And then, medical model thinking being what it is, it was, "Just to be on the safe side, let's just put the baby under the lights if the count is 12." In other words, the decision to treat with phototherapy is not tied to the risk of clinical harm.

-- Henci