CNA Explains: What is cord blood banking and why do parents do it?

SINGAPORE: About 2,200 cord blood units have been damaged after seven tanks at Singapore-based private cord blood bank Cordlife were found to be exposed to temperatures above acceptable limits.

Singapore's Ministry of Health (MOH) said on Thursday (Nov 30) that it found the affected storage tanks have been exposed to temperatures above -150 degrees Celsius.

The damaged cord blood units belonged to about 2,150 clients. Another 17,000 clients could be affected, pending investigations.

Cord blood contains a rich source of blood stem cells that have strong regenerative properties. These stem cells have been proven to be useful in the treatment of many blood disorders and cancers.

What is cord blood banking?

Cord blood is the blood that circulates through the umbilical cord between a foetus and the placenta. It is left in the cord and placenta after the baby is born.

The umbilical cord, placenta and residual blood are usually discarded after birth, but parents can choose to bank their child's cord blood.

The collection process is painless, safe and poses no risk to the mother and baby, said Singapore Cord Blood Bank, the only public bank in the country.

After the baby is delivered, the umbilical cord is clamped and cut, and the cord blood is collected from the umbilicus vein before the placenta is delivered. This collection can only take place at the time of delivery.

Cord blood is usually processed within 36 to 48 hours of collection. At the end of processing, the final product is a 25ml bag of white blood cell concentrate.

A cryoprotectant is added to protect the cells during the preservation process and the freezing bag is placed in an aluminium case and into a holding rack. 

The processed cord blood unit is then gradually frozen until the temperature reaches below -180 degrees Celsius. It is transferred to a storage tank that is maintained at a temperature lower than -150 degrees Celsius.

Why do parents choose to bank cord blood?

Blood stem cells have been used since the 1960s for stem cell transplants, said online platform HealthHub. This treatment can potentially cure many diseases, especially blood cancers.

But many patients in need of stem cell transplants do not have these blood stem cells, which are usually sourced from a matching sibling. 

"However, many patients are from single-child families ... or all siblings do not match in some cases. As a result, many of these patients die," said HealthHub.

Cord blood unit storage is a service that has emerged over the last 20 years, said MOH.

According to healthcare group SingHealth, cord blood contains newborn stem cells that adapt to any environment, making it ideal for transplantation in cancer patients whose immune systems are already impaired from chemotherapy or radiation therapy.

While chemotherapy and radiation therapy destroy cancer cells, they also destroy stem cells. An infusion of stem cells or a transplant is performed after the chemotherapy or radiation therapy.

The stem cells then migrate to the patient's bone marrow, regenerating the blood cells needed to create a new blood and immune system.

According to the Singapore Cord Blood Bank, more than 35,000 cord blood transplants have been performed globally to treat diseases, including blood cancers like leukaemia and lymphoma. 

Many of these transplant patients received unrelated cord blood that was donated to a public bank.

Six people in Singapore are diagnosed with blood-related cancers every day. More than two-thirds of those diagnosed with these conditions are unable to find a suitable stem cell unit from an adult bone marrow donor, said SingHealth on its website.

Doctors have also found the benefits of using cord blood in transplants "far exceed" that of adult bone marrow, it added.

Public vs private: What's the difference?

Singapore Cord Blood Bank is the only public bank in the country. Besides Cordlife, Singapore has two other private cord blood banks: Cryoviva and Stemcord.

Singapore Cord Blood Bank was officially opened in September 2005.

According to Singapore's National Library Board, the public cord blood bank was opened in response to demand from paediatricians and haematologists to increase the number of cord blood units available for unrelated stem cell transplant patients.

Ten hospitals in Singapore offer public cord blood donation and direct family cord blood banking. They are KK Women’s and Children’s Hospital, National University Hospital, Singapore General Hospital, Gleneagles, Mount Alvernia, Mount Elizabeth (Orchard and Novena), Parkway East, Raffles and Thomson Medical.

If cord blood is stored in a public bank, it is for everyone – the donor does not have exclusive rights to their blood stem cells. In a private bank, it is kept for the child's personal use.

Cord blood donations to a public bank are voluntary, confidential and at no cost to the donor.

But keeping cord blood at a private bank comes at a cost. 

Cordlife charges an annual fee of S$250 when a child is aged between 1 and 20. When the child reaches 21, they will have direct ownership of their cord blood and have to decide whether or not to continue storing it.

Cordlife customers are also charged an upfront initial payment, although the amount is not made known on Cordlife's website.

Stemcord says on its website that customers can bank their child's cord blood for "as little as S$0.80 per day". It offers various pricing plans, although potential customers will have to enquire about prices.

Cryoviva’s price plan is not published on its website.

All three private cord blood banks in Singapore allow parents to make payments using the Child Development Account - a savings scheme which can be used for a child's healthcare expenses. 

The Singapore Cord Blood Bank also offers private cord blood banking. With this service, parents can initially store the cord blood units for their family and later donate them to the public inventory, if it meets the necessary public donation criteria.

The BBC reported in August that the global cord blood banking market was valued at US$1.3 billion in 2020, and is expected to grow to US$4.5 billion in the next decade. 

What are the limitations of cord blood?

The American College of Obstetricians and Gynaecologists (ACOG) said on its website that a disadvantage of cord blood is that it does not contain many stem cells.

"Units from several donors can be combined to increase the number of stem cells if a transplant is needed for an adult," said the ACOG.

A child's stem cells also cannot be used to treat genetic diseases in that child. All of the stem cells have the same genes that cause the disease.

In an updated policy in 2017, the American Academy of Pediatrics (AAP) said that the private cord blood banking industry "emphasises the biological insurance of cord blood stored in its banks for potential use later in the child's life".

But it added that there is "little evidence supporting this purpose".

"There’s a mistaken belief that an infant’s stem cells stored in a private cord blood bank can be used if the child develops leukaemia later in life," said the AAP.

"Scientific evidence, however, shows that an infant’s stem cells already contain pre-malignant leukemic cells, and treatments have resulted in the reappearance of leukaemia.

"The chances that an infant’s cord blood cells will be used for transplantation are 30 times greater in the public cord blood banking system as compared with private cord blood banking."

According to the Singapore Cord Blood Bank, cord blood units in the public bank would be available for the patient who needs it the most – that could be the donor or someone else.

Although the donor will have priority, in an unlikely case where the same blood unit is needed, it would be up to a transplant physician to determine if it is wise to use the donor's own cord blood unit.

Data has shown that it is "most unlikely" that the donor should ever need their own cord blood unit, as most transplant physicians may not feel that it is the best choice.

"This is because it may already carry the genetic abnormality that led to the blood or immune system failure or cancer in the first place," it said on its website.