Donated umbilical cord blood is used to treat many diseases. How does it work?
What is an umbilical cord blood donation?
When a baby is born, blood from the cut umbilical cord is particularly rich in stem cells. This is called umbilical cord blood.
If the parents consent, the blood is collected using a simple procedure. Stem cells in the cord blood can be used to treat several serious diseases. Héma-Québec manages the only public cord blood bank in Quebec.
The collection of cord blood is safe for both the mother and her newborn. When it’s not collected, cord blood is discarded as biomedical waste, just like the placenta.
What are umbilical cord blood stem cells used for?
Stem cells are parent cells from which all other blood cells (red blood cells, white blood cells, and platelets) are formed. When cord blood is collected, only the white blood cells are kept, as the stem cells are found among them. Stem cells are the only cells capable of reconstituting a person’s entire immune system.
Stem cells are normally found in bone marrow. Certain diseases (e.g., leukemia, genetic defects) and medical treatments have the side effect of destroying bone marrow or causing it to malfunction. The production of blood cells is therefore compromised, which can be life-threatening. Doctors must then perform a stem cell transplant to replace the bone marrow cells.
Bone marrow transplants are also possible, as bone marrow, like cord blood, is rich in stem cells. However, bone marrow transplants require finding a matching donor, usually a relative. Unfortunately, there is only a 25 percent chance of finding a compatible donor in a patient’s family. Since Quebec families tend to be smaller and smaller, the likelihood of finding a related donor is even lower.
Another option is the international Stem Cell Donor Registry, which includes a list of unrelated stem cell donors. The probability of finding a compatible donor in less than six months is 60 percent. For patients with certain medical conditions, cord blood is an attractive alternative for obtaining compatible stem cells.
The benefits of umbilical cord blood
Stem cells in cord blood have high plasticity and adapt more easily to the recipient than those found in bone marrow. That means matching requirements are less strict for a stem cell transplant. When testing for compatible bone marrow, 10 genes are compared between the donor and recipient, whereas only 8 genes are compared when testing cord blood. It is therefore much more common to find a compatible donor from a cord blood bank.
To facilitate the search for compatible donors, the cord blood bank must have samples from a wide range of ethnic backgrounds. For this reason, donations from all cultural communities are welcome. In addition, cord blood from babies born to parents of different ethnicities (e.g., an African father and an Asian mother or an Indigenous mother and a Caucasian father) is particularly sought after.
Given the small amount of blood in an umbilical cord, few stem cells are collected per sample. This treatment option is therefore intended for people weighing less than 50 kg (110 lb.), in other words, primarily children. However, ongoing research on double-unit cord blood transplants in adults has had promising results.
Much progress has been made since the first cord blood transplant in 1988. At CHU Sainte-Justine, such transplants are performed about 30 times a year, with excellent results. Cord blood is mainly used to treat leukemia, certain immune deficiencies, and certain forms of anaemia. Over the years, new ways of using cord blood for the treatment of diseases have come to light.
How do I make a donation?
In the province, eight hospitals offer expectant mothers the possibility to register with the Public Cord Blood Bank: St. Mary’s Hospital, CHU Sainte-Justine, Royal Victoria Hospital, CHUL et Centre mère-enfant Soleil, Hôpital de la Cité-de-la-Santé, LaSalle Hospital, Hôpital du Sacré-Coeur de Montréal, and Lakeshore General Hospital.
To donate cord blood, interested mothers must meet certain criteria. They must be healthy and over 18 years of age. They must also not be pregnant with twins. The cord blood bank registration form must be completed before the 36th week of pregnancy.
A nurse from Héma-Québec will contact registered mothers as of the 25th week of pregnancy to complete a qualification form.
How is cord blood collected?
Donating cord blood is a simple procedure. After the baby is born and the umbilical cord is severed, but before the placenta is expelled, up to approximately 150 ml of blood is drawn from the umbilical vein with a needle.
The blood is then analyzed. If the tests reveal that the blood can’t be stored in the public bank (for example, if a unit of cord blood contains too few cells), it may instead be donated to a university hospital for research purposes.
The blood is processed and frozen in liquid nitrogen. It can be stored in these conditions for at least 10 years. Therefore, any child in Quebec who needs a cord blood transplant can receive one, whether or not their own cord blood was donated.
Umbilical cord blood collection and delayed clamping
Studies carried out in recent years indicate that waiting at least one minute to clamp the umbilical cord after birth may benefit the baby. The extra blood may translate into a higher birth weight, a higher hemoglobin concentration, and better iron stores in the baby’s first 6 months of life.
Although delayed clamping may reduce the amount of blood collected, it doesn’t prevent mothers from donating cord blood. In some cases, the volume of blood in the umbilical cord is higher than expected. Therefore, even if clamping is done later, there will be enough blood for stem cell collection.
The baby’s well-being always takes precedence over the cord blood donation. If delayed clamping is important to the parents, they should mention it to their doctor, who will then wait to clamp the cord and collect the cord blood afterwards. The donation will then be sent to Héma-Québec, where staff will determine if it has enough cells to be banked.
Public or private cord blood banking
The stem cells from donations made to a public bank like Héma-Québec’s are accessible to everyone, just like blood donations. Many private companies offer the same service for a few thousand dollars.
The difference with donating to a private bank is that your baby’s stem cells are stored for their own future use. Since private companies are profit-driven, they pitch their services as a unique chance to save your child’s life, should they one day be afflicted with a critical illness.
It can be tempting to keep cord blood that you know will be a perfect match in a private bank for personal use. The vast majority of private banks process cord blood under controlled conditions. That said, parents are responsible for sending their samples to the bank themselves. This can lead to problems with the collection kit before the baby’s delivery or after collection. It may also increase the risk of improper storage.
Furthermore, cord blood is only viable for about 10 years, when properly stored. The likelihood that your child will need to use their own banked cord blood is between 1 in 20,000 and 1 in 200,000. Experts therefore recommend that parents donate their cord blood to a public bank, which is free.
Things to keep in mind
Collecting cord blood is safe for the mother and baby.
Cord blood can be collected even if the mother wishes to wait at least one minute after delivery to cut the cord (i.e., delayed clamping).
Presently, cord blood is mainly used to treat leukemia, certain immune deficiencies, and certain forms of anaemia. However, researchers are exploring new ways of using cord blood for the treatment of diseases.
Scientific review: Dr. Guy Sauvageau, hematologist
Stem Cell Transplant Centre, Department of Hematology, Maisonneuve-Rosemont Hospital
Research and copywriting: The Naître et grandir team
Updated: March 2020
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Armson, B. Anthony, et al. “Umbilical Cord Blood: Counselling, Collection, and Banking.” Journal of Obstetrics and Gynaecology Canada, vol. 37, no. 9, 2015. pp. 832–844. www.jogc.com.
Héma-Québec. “Umbilical cord blood donation.” www.hema-quebec.qc.ca.