Is there any reason to delay cord clamping?

A new study being widely reported in the mainstream media has recommended delayed cord clamping. However, the authors acknowledge that there is no scientific evidence that delayed cord clamping provides any benefits for term infants; their recommendation is based on pure speculation.

The paper entitled Mankind’s first natural stem cell transplant appears in the Stem Cell Review Series of the Journal of Cellular and Molecular Medicine. The authors of the paper include the founder and chairman of Saneron CCEL Therapeutics, Inc. a company that harvests stem cells from umbilical cord blood to use in developing new treatments for neurodegenerative and other diseases. It appears that the primary purpose of the paper is to demonstrate that cord blood collection for banking or research does not require immediate clamping of the umbilical cord.

The authors acknowledge that there is no demonstrated benefit to delayed cord clamping in term infants. While some studies show a reduced incidence of anemia in the first 6 months of life, this is only clinically important in developing countries where anemia is common in infants and children. The authors focus instead on potential benefits of transferring additional stem cells from the umbilical cord blood to the baby’s bloodstream.

The authors make much of the fact that delayed cord clamping leads to the baby’s “first stem cell transplant.”

… autologous transplantation of stem cells naturally occurs in nature at birth in mammals via the umbilical cord. A delay in the cord blood clamping may increase the stem cell supply to the baby, thereby allowing an innate stem cell therapy that can promote acute benefits in the case of neonatal disease, as well as long-term benefits against age-related diseases….

Yet the authors don’t provide any reason why a term baby has any need of or derives any benefit from a stem cell transplant. There is no scientific evidence that early cord clamping leads to a deficit of stem cells in the neonate or that delayed cord clamping has any impact on any neonatal system dependent on stem cells. The purported benefits are all entirely theoretical.

As any doctor knows, the history of medicine is littered with ideas that seemed to be great in theory, but surprisingly turned out to be dangerous in fact. Consider the use of 100% oxygen in the first incubators of the 1930’s. Reasoning that if some oxygen is good, more must be better, premature infants having difficulty breathing were treated with pure oxygen. It may have been better from a respiratory point of view, but it unexpectedly rendered many of the infants blind. That’s because the sensitive tissues of the retina develop best in a low oxygen environment, but no one knew this until they learned of the damage that resulted from exposure to 100% oxygen.

The reasoning behind delayed cord clamping is the same: adequate red blood cells are good, more must be better; adequate umbilical stem cells are good, more must be better. But we really don’t know whether either of those claims are true. As the authors acknowledge:

One important point to consider is the long-term effects of delayed cord clamping. The present authors are unaware of any studies in either animals or human beings that followed the organism to adulthood. In human beings the longest studies go to 6–7 months and some benefits can still be observed with respect to iron status and motor disability. It is crucial to perform long-term follow-up studies to determine whether the reported benefits of delayed cord clamping are long term, or whether additional benefits may become apparent.

It never even occurs to the authors to investigate whether there might be harms from delayed cord clamping. After all, some umbilical cord blood is good, more must be better, right? Wrong. Without studying the matter we have no idea of the long term benefits or risks. It is irresponsible to recommend delayed clamping as the standard until we have scientific evidence that it provides benefits without leading to unexpected harms.