The Great Clamping Debate
Most of us born after 1960 have missed out on what was, since ancient times, “mankind’s first stem cell transplant.”1
For umbilical cords of most born after 1960 were—are—clamped right after birth. This denied us a last blast of stem-cell rich placenta blood, 40% of our circulation, before our first breath.
This is rare in animal evolution. “Most mammals…wait until the expulsion of the placenta to sever the umbilical cord,” noted Tonse Raju, a National Institutes of Health (NIH) child health expert, in the December Clinics in Perinatology.
But thanks to new research, obstetric and neonatal experts from around the world will convene an unusual meeting in a few days. The agenda: to discuss advising “mankind” to return to ancient birthing methods, and restore those ancient stem cell transplants.
If they do—and convince professional associations to follow—the move could impact public and private umbilical cord banks, umbilical cord research, and babies everywhere.
A watershed study this month is already attracting attention, says David Hutchon, past president of the North of England Obstetrical and Gynaecological Society. Led by the University of Monash’s Stuart Hooper, the study found immediate clamping disrupts cardiovascular flow.2
“It shows a profound reduction in heart output, blood pressure, and circulation in the brain directly caused by early cord clamping,” says Hutchon. It “dispels the view that cord clamping is a benign intervention with minor disadvantages.” Experts at the Cutting the Cord meeting on April 19 will discuss “how early clamping can be avoided in all births.”
Studies reviewed in April’s Current Opinion3 find that if most of us had had delayed clamping, we would have had: a) higher hemoglobin and hematocrit neonatally b) higher body iron and circulating ferririn stores at 2-4 months c) lower indices of iron deficiency anemia at four months.
Such research convinced the International Liason Committee on Resuscitation in 2010 to advise delay in cord-cutting at least one minute post-birth in normal infants. The same year, the European Association of Perinatal Medicine advised clamping delays of at least 35-45 seconds.
In a 2012 update, the World Health Organization advised clamping delay in normal infants up to three minutes. And while the Royal College of Obstetricians and Gynaecologists (RCOG) and the American College of Obstetricians and Gynecologists have not advised against early clamping for normal infants, both want more research.
“Immediate cord clamping became routine practice without rigorous evaluation,” said a 2009 RCOG Scientific Impact paper. Yet “infants who have immediate cord clamping have lower iron stores for up to six months after birth….Iron deficiency in the first few months of life is associated with neurodevelopmental delay, which may be irreversible. As this has implications for every birth, even a modest difference in beneficial or harmful effects would be important.”
That was before cardiovascular consequences were mined. Now Hooper has found cardiovascular benefits when the cord in lambs remained unclamped three to four minutes after breathing. “If breathing begins before the cord is clamped,” he confirmed via email, “the cardiovascular transition is much smoother and less likely to cause problems for the baby.”
Still, change could bring opposition. A move to advise delayed clamping could affect cord blood banking for transplants, research, and private industry. The reason: the earlier cords are clamped, the more stem cells they can offer, some report.4
And the field is growing. The World Marrow Donor Association lists half a million units of cord blood in 60 public banks in 40 nations. Each cord is worth $20,000 to $40,000. Cord blood transplants have swelled from one in 1998 to 50,000 a year. Global public banking is worth well more than $30 million. A large private banking sector has emerged.4, 5
This, coupled with recent scientific gains (see our cord blood story) means cord blood is taking “an increasingly significant role in the regenerative medical bio-economy,” reported Nik Brown, University of York sociologist.4, 5
Still, there is no agreement on how affected the cord blood industry would be. Many banks say they only do later ex utero (post placenta-expulsion) collection anyway. Some research indicates “in” versus “ex” utero collection doesn’t affect cell quality.6 Other reports say that timing matters, and that some birth experts do feel industry pressure to clamp earlier.4
Surely, obstetricians would be impacted. Says Hutchon: “Some obstetricians and neonatologists have been reluctant to think that suddenly clamping off 40% of the baby’s circulation through the placenta might be harmful. They say we’ve been doing it for years and babies seem to do fine. Most babies seem to do fine. But some do not.”
There may be medical reasons not to delay, including a 2% increased need for phototherapy (light therapy) when clamping is delayed.3
Regardless, cord blood science is advancing. Two cords are now used for larger patients. Many groups can expand the once-recalcitrant cells in labs. And studies confirm the cells are less immunogenic than adult stem cells.7 Much graft v. host disease occurs. But cord blood does offer immunological advantages.
Finally, the NIH may pursue public/private partnerships to minimize waste of cells.8 So transplanters may do more, with less, if the move to delayed clamping continues.
Hutchon hopes it will. “Suddenly deprived of an oxygen supply…” he says.
“Imagine how the baby feels.”
1. Tolosa, J. N., et al. “Mankind’s first natural stem cell transplant,” Journal of Molecular Medicine, Vol 14 Iss 3, 2010: 488-495.
2. Bhatt, S., et al, “Delaying cord clamping until ventilation onset improves cardiovascular function at birth in preterm lambs,” Journal of Physiology, published online before print March 19, 2013.
3. Raju, T., et al. “Timing of umbilical cord clamping after birth for optimizing placental transfusion,” Current Opinion, Vol 25 Iss 2, April 2013: 180-187.
4. Brown, N., et al, “Contradictions of Value: between use and exchange in cord blood bioeconomy,” Sociology of Health and Illness, Vol 34 Iss 1, January 2013: 97-112.
5. Brown, N., et al. “Immunitary bioeconomy: The economization of life in the international cord blood market,” Social Science & Medicine, Vol 72 Iss 7, April 2011: p1115-1122.
6. Lasky, L.C., et al. “In utero or ex utero cord blood collection: which is better?” Transfusion, Vol 42 Iss 10, October 2002: p1261-1267.
7. Kanda, J., et al. “Unrelated cord blood transplantation vs related transplantation with HLA 1-antigen mismatch in the graft-versus-host direction,” Leukemia, Vol 27 Iss 2, July 18, 2012: p286-294.
8. Rao, M., et al. “Concise Review: Cord Blood Banking, Transplantation and Induced Pluripotent Stem Cell: Success and Opportunities,” Stem Cells, Vol 30 Iss 1, January 2012: p55-60.