What Is Cord Blood? Stem Cells, Medical Uses and Cord Blood Banking
Contents
- What Is Cord Blood?
- Which Stem Cells Does Cord Blood Contain?
- What Conditions Can Cord Blood Be Used to Treat?
- Can a Child Use Their Own Cord Blood?
- What Are the Potential Future Uses?
- Public vs Private Cord Blood Banking
- When May Directed Family Banking Be Considered?
- How Is Cord Blood Collected?
- Does Delayed Cord Clamping Affect Collection?
- How Is Cord Blood Stored?
- How Long Can Cord Blood Be Stored?
- What Are the Advantages and Limitations?
- Frequently Asked Questions
Cord blood is the blood remaining in the placenta and umbilical cord after birth. It contains haematopoietic stem and progenitor cells that can be used as a source for stem-cell transplantation in appropriately selected patients.
What Is Cord Blood?
Cord blood is the blood remaining within the placenta and umbilical cord after the baby has been born and the cord has been clamped.
This blood can be collected under sterile conditions, processed and cryopreserved as a potential source of haematopoietic stem cells.
Which Stem Cells Does Cord Blood Contain?
The main clinical value of cord blood comes from haematopoietic stem cells.
These cells can reconstitute the blood-forming system and produce red blood cells, white blood cells, platelets and multiple immune-cell populations.
Cord blood can therefore provide an alternative source of haematopoietic stem cells to bone marrow or peripheral-blood stem cells.
What Conditions Can Cord Blood Be Used to Treat?
Cord-blood haematopoietic stem cells can be used as a transplant source for selected patients with conditions including some:
- Leukaemias
- Lymphomas and other haematological malignancies
- Bone-marrow failure disorders
- Haemoglobin disorders
- Inherited immune-system disorders
- Inherited metabolic disorders
The suitability of a cord-blood unit depends on the patient's disease, HLA compatibility, cell dose and the availability of other stem-cell sources.
Can a Child Use Their Own Cord Blood?
Autologous use of stored cord blood has important limitations.
If a child develops an inherited genetic disorder, the child's stored cord-blood cells may carry the same genetic alteration.
In certain childhood leukaemias, the stored cord blood may also contain premalignant cellular abnormalities and may therefore not be an appropriate autologous transplant source.
What Are the Potential Future Uses?
Cord-blood and cord-derived cells continue to be investigated in regenerative-medicine research.
Research has included neurological disorders, cerebral palsy, diabetes and various forms of tissue injury.
However, experimental research should be clearly distinguished from established clinical therapy.
Public vs Private Cord Blood Banking
Public Banking
When available, eligible families may donate cord blood to a public bank. Units meeting the required quality standards can enter a registry and potentially be used for an appropriately matched patient.
The donated unit is not reserved exclusively for the donor's family.
Private Banking
Private banks store cord blood for potential future use by the child or family, generally for a fee.
However, future use cannot be guaranteed and the unit may not be suitable for the condition that eventually develops.
When May Directed Family Banking Be Considered?
Directed collection can be clinically relevant when a family already has a child or close relative with a condition potentially treatable by haematopoietic stem-cell transplantation and the newborn may be a suitable donor.
Such situations should ideally be discussed during pregnancy with the obstetric team and the relevant haematology or transplant service.
How Is Cord Blood Collected?
Collection takes place after birth and after the umbilical cord has been clamped and cut.
- The baby is born and immediate newborn care takes priority.
- The cord is clamped and cut at the clinically appropriate time.
- Blood remaining in the cord and placenta is collected into a sterile collection bag.
- The unit is labelled and transported for testing, processing and storage.
The blood is collected from the placental-cord circulation rather than directly from the baby's bloodstream.
Does Delayed Cord Clamping Affect Cord Blood Collection?
Yes. Delayed cord clamping allows additional placental blood to transfuse to the newborn and may consequently reduce the volume and number of cells remaining for cord-blood collection.
However, cord-blood banking should not compromise routine maternal or neonatal care.
How Is Cord Blood Stored?
After collection, the unit undergoes quality assessment, infectious-disease testing and processing according to the cord-blood bank's protocol.
It is then cryopreserved under controlled conditions and stored at very low temperatures.
Not every collected unit contains a sufficient number of viable cells to meet transplantation-quality requirements.
How Long Can Cord Blood Be Stored?
There is no universal biological rule that a cord-blood unit automatically becomes unusable after 20 or 25 years.
Published long-term stability data have demonstrated preservation of high cellular viability in appropriately cryopreserved cord-blood units for up to 29 years.
The practical storage period depends on the bank's validated procedures, regulatory requirements, quality programme and contractual terms.
What Are the Advantages and Limitations?
Potential Advantages
- Collection takes place after birth.
- It provides a source of haematopoietic stem cells.
- A stored suitable unit can be rapidly available when needed.
- Cord blood may permit transplantation with less stringent HLA matching in some circumstances.
Limitations
- The number of stem cells in a single unit is limited.
- Cell dose may be insufficient for some larger children and adults.
- Blood-cell recovery after transplantation can be slower than with some other stem-cell sources.
- The child's own unit may not be suitable for genetic diseases.
- Autologous use may be inappropriate for certain childhood leukaemias.
- Future use is not guaranteed.
Consider Your Options Before Birth
If cord-blood collection is being considered, public donation, private storage, family medical history and the birth plan can be discussed during pregnancy.
Frequently Asked Questions
References
- Academic Hospital. Cord Blood
- American College of Obstetricians and Gynecologists. Umbilical Cord Blood Banking
- American College of Obstetricians and Gynecologists. Delayed Umbilical Cord Clamping After Birth
- U.S. Food and Drug Administration. Cord Blood Banking – Information for Consumers
- American Academy of Pediatrics. Cord Blood Banking for Potential Future Transplantation
- Querol S, et al. Long-Term Stability of Cord Blood Units After 29 Years of Cryopreservation