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CION Cancer Clinics
Risks to the donor: what can go wrong, and how likely it is | CION Cancer Clinics
For a healthy donor who has passed the health check, serious harm from donating stem cells or bone marrow is rare. Discomfort is common: bone ache from the injections, tingling on the machine, or a sore lower back after a marrow harvest. Most donors recover fully as the body replaces what was given. This page sets out the real risks of each route, and the signs that need a same-day call. At CION Cancer Clinics, our haematology team assesses whether a transplant or CAR-T fits your situation and coordinates care with qualified centres.
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Medically reviewed by Dr. Basudev PokhrelConsultant Haematologist · last reviewed September 2026, next review due September 2027
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On this page
- How risky is it to donate bone marrow or stem cells?
- What can go wrong when stem cells are collected from the blood?
- What are the risks of a bone marrow harvest?
- Which fears about donating are not true?
- What do the risk words on the consent form mean?
- What can this page not tell you about your own risk?
- Common questions about risks to the donor
The short answer
How risky is it to donate bone marrow or stem cells?
For a healthy donor who has passed the health check, serious harm is rare. Discomfort is common. Most donors have aches, tiredness or a sore back for days to weeks, and then recover fully as the body replaces what was given.
Why the risk is low, but not zero
You give a part of your blood-forming cells, and your body makes more. The risks come mainly from the steps around that: the injections, the needles and machine, or the anaesthetic for a marrow harvest. Any medical procedure carries some chance of a problem, and donating is no different. Anyone who tells you there is no risk at all is not giving you the full picture.
Why the health check matters so much
The donor health check exists to find the people for whom donating would be riskier. It looks at your heart, blood counts, infections, pregnancy, past illnesses and medicines. Being honest there is the single most useful thing you can do for your own safety.
Your donor doctor should be someone other than the doctor treating the patient, so your safety is looked at on its own.Donating from the blood
What can go wrong when stem cells are collected from the blood?
Most donors give this way. The effects below run from very common to uncommon.
Injection effects
Bone ache, headache, tiredness and flu-like feelings during the injection days. Very common, and they fade after the injections stop.
Low calcium on the machine
The anti-clotting liquid used in the machine can cause tingling around the lips and fingers, or cramps. The nurse treats it quickly if you say so.
Low platelets afterwards
The machine removes some platelets, the cells that help blood clot. You may bruise more easily for a few days while the count recovers.
Uncommon but important
These are the reasons the team watches you closely.
Rarer problems
- A swollen spleen, very rarely a tear
- An allergic reaction to the injection
- Problems with a line placed in a large vein
Not sure whether this applies to you?
Ask an oncologistDonating from the bone
What are the risks of a bone marrow harvest?
A marrow harvest is done under general anaesthetic. The main risks are the ones that come with any anaesthetic, and the soreness where the needles went into the hip bones.
The anaesthetic
Feeling sick, a sore throat from the breathing tube, and grogginess are common and short-lived. Serious reactions to anaesthesia are rare in healthy adults. The anaesthetist will see you beforehand and ask about your health, allergies and any past problems with anaesthesia in you or your family.
The hip and lower back
Pain, stiffness and bruising low in the back are expected. For most donors this eases over days to a few weeks. Less often, the needle sites can become infected, or bleed more than expected. Very rarely a nerve or bone is irritated and pain lasts longer.
Tiredness and low blood count
Losing some marrow and blood can leave you tired for a while, with a lower haemoglobin, the protein that carries oxygen. Some donors are given iron, and a few centres return a bag of the donor's own blood, stored earlier. Eat well, rest, and tell the team if the tiredness is not lifting as the weeks go on.
!
Signs that need a same-day call
Before or after donating, call the donor team the same day for pain under the upper left ribs or at the tip of the left shoulder, a fever or shivering, redness or pus at a needle site, bleeding that will not stop, breathlessness or chest pain. If you cannot reach them, go to the nearest emergency department or call 108 and say you have recently donated stem cells.
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Commonly believed
Which fears about donating are not true?
"Donating marrow can leave you paralysed."
Marrow is taken from the back of the hip bones, not the spine. The spinal cord is not touched. This fear stops many families from even being tested.
"You lose your immunity after donating."
You give a part of your stem cells, and your body rebuilds its supply. Your immune system keeps working. There may be a short spell of lower counts, which the team checks.
"Men who donate lose strength or fertility."
There is no evidence that donating affects strength, fertility or sexual function in the long run. Tiredness after donating is temporary.
"The injections will give the donor cancer."
Large studies of healthy donors followed over years have not shown a clear rise in blood cancers. Research continues, and it is reasonable to ask your donor doctor what is currently known.
On the consent form
What do the risk words on the consent form mean?
- General anaesthetic
- Medicine that puts you fully to sleep for the marrow harvest.
- Central venous line
- A thin tube placed in a large vein, used only if arm veins are too small for collection.
- Citrate reaction
- Tingling or cramps from the anti-clotting liquid in the machine, caused by a dip in calcium.
- Splenic enlargement
- Swelling of the spleen, an organ under the left ribs, which can happen with the injections.
- Donor follow-up
- Calls or check-ups after donating, to make sure you have recovered and to track donor health over time.
Being straight with you
What can this page not tell you about your own risk?
It cannot tell you how risky donating is for you personally. That depends on your age, weight, veins, past illnesses, medicines and results from the health check. Only the donor doctor who has examined you can weigh those.
Who donating may not suit
People with some heart, lung, clotting or autoimmune conditions, people who are pregnant, and people with certain infections are often not cleared to donate. Being turned down is a safety decision, not a judgement. The patient's team will look at other donors.
Questions worth asking
Ask what problems the centre has seen in its own donors, who you call at night, who pays if you need treatment for a donation problem, and whether you will be followed up afterwards. A good donor team will answer these openly.
The risks that are not physical
Donating for a relative can carry a heavy emotional load. Some donors feel responsible if the transplant does not go as hoped, even though the outcome depends on the disease and the patient, not on the donor. Others feel pressure from family to agree. Both are common, and it is reasonable to ask the centre for a counsellor before and after donating.
Questions donors ask
Common questions about risks to the donor
Has anyone died from donating stem cells?
Deaths linked to donation have been reported worldwide, but they are extremely rare. Many involved donors with conditions that careful screening now looks for. This is why the health check is thorough and why you should be completely honest there. Ask your donor doctor to explain the risks in your own case.
Will donating shorten my life?
There is no evidence that donating stem cells shortens a healthy donor's life. Your body replaces the cells you give. Donor registries follow donors over years to keep checking this, and so far the long-term picture for healthy donors has been reassuring.
Can I donate a second time if asked?
Sometimes the patient needs a second donation, or extra immune cells. It is possible for many donors, but it is a new decision. You are checked again, and you can say no. Ask about the risks of repeat donation at that point.
Is it riskier for older donors?
Older donors are more likely to have health conditions that raise the risk, especially with anaesthesia. The health check takes age into account. A parent donating for a child, for example, may be checked more closely than a young adult sibling.
Who pays if something goes wrong for me?
This varies between centres, registries and insurers in India. Ask for the answer in writing before you consent. Check whether the patient's insurance or scheme covers donor complications, and whether your own health insurance does.
Does donating affect a future pregnancy?
There is no known effect on future pregnancy for donors who have recovered. You should not be pregnant at the time of donation, and a pregnancy test is usually part of the check. If you are planning a pregnancy soon, tell the donor doctor.
What if I have diabetes or high blood pressure?
Well-controlled conditions do not always rule you out, but they change the picture. Bring your reports and every medicine to the health check. Do not stop or change a medicine to look healthier on the day. The donor doctor needs the real picture.
Can I change my mind after hearing the risks?
Yes. Hearing the risks is exactly when many donors think it over again. Tell the team as early as you can, because the patient's treatment plan is built around the donor. The team should respect your answer without pressure.
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Dr. Basudev Pokhrel reviews blood counts, transfusion needs and blood disorders, and works with the CION tumour board on blood cancers.
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Sources
- American Cancer Society — Stem cell transplant donors
- NHS — Stem cell and bone marrow transplants
- National Cancer Institute — Stem Cell Transplants in Cancer Treatment
- NHLBI — Blood and Bone Marrow Transplant
This page is general information, not a prescription. Do not change or stop any treatment based on what you read here. If anything is worrying you, contact your own treating team — or call our helpline and we will help you reach the right specialist.
Keep reading
Related pages
Peripheral Blood vs Bone Marrow HarvestHow the two routes compare for youG-CSF Injections Before Donation and How They FeelThe most common effects, day by dayDonor Eligibility: Age, Weight and Health ConditionsConditions that make donating unsafeCan a Donor Say No?Your right to decline, and when to say so
Talk to us
Weighing up whether to donate?
Tell us where things stand. Our haematology team will talk through the risks with you and help you reach a qualified transplant centre. One helpline serves every CION centre.