Elaborating on the tweetorial based on ACOG’s Update of the Umbilical Cord Blood Banking Recommendations
Quick Read | Fetal Medicine | 3 min read
While the placenta grabs the attention of parents, its companion the umbilical cord despite its proven therapeutic potential is not as frequently talked about during the course of pregnancy. In the backdrop of the American College of Obstetricians and Gynaecologists’ (ACOG) update on Umbilical Cord Blood Banking Recommendation in February 2019 (last update was in 2015), let’s review some basics of the umbilical cord for clinical practice and blood banking.
What is an umbilical cord?
An umbilical cord links the fetus to the placenta. It usually contains one umbilical vein and 2 umbilical arteries surrounded by the gelatinous Wharton’s jelly. Within these lie hematopoietic, mesenchymal and embryonic-like stem cells. On gross and histological analysis of the umbilical cord, arteries and vein can be differentiated easily due to their distinct lumen size and thickness of the muscularis.
The umbilical cord: Diagrammatic schema showing vessels and the pressures within each.
Source: Anatomy Body Charts
Top right and top left: umbilical artery, bottom: umbilical vein, middle: remnant of allantois.
Source: Wikimedia Commons | Dr Ed Uthman
Observe and learn: are all umbilical cords identical?
In an average labour and delivery ward, maternity care providers are pressed to care for both the mother and babies. But if opportunity allows and you have a minute or two, spend some time looking at the placenta and the umbilical cord, and observe the length, thickness and coiling as they can point to various gestational pathologies. The Amsterdam Placental Workshop Group Consensus Statement on Sampling and Definitions of Placental Lesions (2015, pages 699-700) provides detailed pointers and selection of lesions of the umbilical cord. For instance, thin umbilical cords are associated with fetal growth restriction while thick cords are associated with maternal diabetes and fetal hydrops. Meanwhile, excessively long and short cords are associated with adverse outcomes, including fetal macrosomia.
An interesting case study was published in the British Medical Journal in 2015, which reported a giant umbilical cord (measuring 10x12cm and weighing a whopping 500gms) in a baby boy delivered at 35 weeks in New South Wales in Australia.
Another case report published in the British Medical Journal about a giant umbilical cord was in 2005 by physicians in Geneva, Switzerland. Surgical repair was eventually performed for a patent urachus diagnosed two weeks after birth.
Where and what are the different types of stem cells found in the umbilical cord?
Stem cells have been localized in nearly all the structures of the umbilical cord, but are differentiated from the site of collection into cord tissue and cord blood. Cord tissue includes the cord lining, Wharton’s jelly, the perivascular region and the endothelium. Cord blood stem cells are specifically derived from within the lumen of the vessel and include hematopoeitic, mesenchymal and very small embryonic-like stem cells.
While the therapeutic potential of cord tissue transplants is under research, cord blood stem cell transplants have been performed since the 1980s. French hematologist Dr Eliane Gluckman carried out the first cord blood transplant at Hospital Saint Louis in Paris in 1988. This was based on work performed by Indiana State University and Biocyte/Broxmeyer researchers on potential of umbilical cord stem cells. Dr Gluckman would later show that unrelated cord blood can be used for stem cell transplants. If you are interested in more about the history and evolution of umbilical cord blood research, the article Umbilical Cord Blood Transplantation: the First 25 Years and Beyond by Drs Karen Ballen, Eliane Gluckman and Hal E. Broxmeyer is highly insightful as it features input by the pioneers of this field.
What is umbilical cord blood biobanking and its relevance in medicine today?
Today umbilical cord blood transplants are used in the treatment of 82 treatable conditions including leukemia, lymphoma, myeloma and myeloproliferative disorders as well as genetic diseases and inborn errors of metabolism.
There are 28 public umbilical cord blood banks in North America with at least 3 based in Canada, including the Canadian Blood Services Cord Blood Bank (Ottawa, Ontario), Héma-Québec (Saint-Laurent, Québec) and Victoria Angel (Markham, Ontario).
In Feb 2019, ACOG released an update to the Umbilical Cord Blood Banking Recommendations. This version adds that available evidence does not support routine use of private biobanks and that publicly funded biobanks are recommended method of obtaining cord bloods.
The American College of Obstetricians and Gynecologists also encourages all ethnicities and minorities to contribute to the umbilical cord blood bank as hematopoietic stem cells to increase the pool. More than 30,000 cord blood stem cell transplants have been performed to date.