There was a study in the BMJ journal based on a sample group in Sweden. Here's a summary:
"In blood tests at two days after birth, there were no significant differences in iron status. But when researchers analyzed blood taken at four months, they found iron concentrations were 45 percent higher in the delayed clamping group, and iron deficiency was significantly more prevalent in those who were clamped early."
http://www.nytimes.com/2011/11/29/he...r=3&ref=health
It's a short article so that's all I have unless you are a BMJ journal member. If you click on the link there is a brief summary and one highlight is that the study recommends a change in routine.
http://www.bmj.com/content/343/bmj.d7127
Beth