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Stem Cell (Bone Marrow) Transplant

Also known as bone marrow transplant (BMT) or hematopoietic stem cell transplant (hsct)

What is a stem cell transplant?

This illustration depicts a long bone with a cross section showing the bone marrow and a callout of blood-forming stem cells that become white blood cells, red blood cells, and platelets.

A stem cell transplant is a medical procedure used to treat a variety of diseases, including childhood cancer and sickle cell disease. It replaces damaged or destroyed blood-forming (hematopoietic) stem cells with healthy blood-forming stem cells.

The main source of stem cells is the bone marrow. Therefore, the procedure is often called a bone marrow transplant (BMT). Some people may also call the process a hematopoietic cell transplant. 

Blood-forming stem cells

Blood-forming (hematopoietic) stem cells are cells that develop into all other blood cells. They mature into cells that eventually become:

  • Red blood cells (which carry oxygen)
  • Platelets (which help the blood clot)
  • White blood cells (which fight infection)

Large numbers of blood-forming stem cells live in the bone marrow. Bone marrow is a soft, spongy material that is in the center of most of the body’s bones. The bone marrow works like a blood cell factory, constantly making new blood-forming stem cells.

There are two types of stem cell transplants:

The stem cell transplant process generally involves:

  • Finding a suitable donor (if allogeneic transplant)
  • Pre-transplant testing and evaluation to make sure the patient is a good candidate for a transplant
  • Collection of stem cells from a donor or the patient
  • Conditioning or pre-transplant treatment using chemotherapy or radiation
  • Infusion of stem cells through a vein, much like a blood transfusion
  • Donor stem cells travel to bone marrow to divide and make healthy blood cells (engraftment)
  • Supportive care to manage side effects and prevent infection

The transplant process is medically challenging. However, receiving the stem cells is a relatively simple process. It is much like a blood transfusion. Stem cells are in a bag or syringe that is connected through a tube to the patient’s central line. It only takes a few minutes to a few hours and is not painful.

After entering the bloodstream, the stem cells travel to the bone marrow, where they begin to divide. Stem cells become white blood cells, red blood cells, and platelets in a process known as engraftment. Engraftment usually happens in 2-4 weeks.) Complete recovery of the immune system may take up to a year.

Learn more about blood by visiting the Basics of Blood website.

There are two basic types of transplants: allogeneic (blood-forming cells come from a donor) and autologous (the patient’s own cells are used). A patient receives cells from the donor through a vein in a process much like a blood transfusion. The cells travel through the bloodstream to the center of the long bones. The transplanted cells restore the patient’s ability to make healthy red blood cells, white blood cells, and platelets.

There are two basic types of transplants: allogeneic (blood-forming cells come from a donor) and autologous (the patient’s own cells are used). A patient receives cells from the donor through a vein in a process much like a blood transfusion. The cells travel through the bloodstream to the center of the long bones. The transplanted cells restore the patient’s ability to make healthy red blood cells, white blood cells, and platelets.

Having a transplant is an option to consider carefully. Patients can have serious side effects and late effects. It is not an easy process and can be hard physically and emotionally for both the patient and family caregivers. But there are many people on the transplant care team to support patients and families along the way. Many children and teens are living active, healthy lives after transplant.

What to expect before a stem cell transplant

Not every patient is a candidate for transplant. The medical team will consider factors such as your child’s:

  • Age
  • General physical condition
  • Diagnosis
  • Prior treatment history
  • Genetic markers for donor matching (if allogeneic transplant)

Blood work and urine tests will be used to measure blood counts, kidney function, liver function, and exposure to infectious diseases. Your child will also have tests to examine the heart, lungs, kidneys, and other vital organs.

Your child will need a central line if one is not already in place.

You will also meet with a social worker or psychologist to discuss emotional and mental health. A financial counselor can help with insurance approvals and financial issues.

What to expect during the hospital stay

Transplant patients usually stay in the hospital at least 4-6 weeks or longer. Your child will stay in a special part of the hospital for transplant patients and other patients who have little or no immune system function. Infection control guidelines are different in the transplant unit than other areas of the hospital.

How to know if transplant is successful

Doctors use various blood tests to confirm that new blood cells are being made (engraftment). After the transplant, your child will have blood drawn daily so it can be tested in the lab. Doctors will count how many red blood cells, white blood cells, and platelets are in the body. Since they are counted each day, doctors and patients can keep track of the progress. Because everyone is different, engraftment can happen at different times. Usually, it takes two weeks to a month. White blood cells are the first to engraft, followed by red blood cells and then platelets. Patients may need transfusions of red blood cells and platelets to keep counts in a safe range during engraftment.

Bone marrow aspiration (the removal of a small sample of bone marrow through a needle for examination under a microscope) can also help doctors see how well the new stem cells are working and if cancer is in remission.

Caring for your child after leaving the hospital

When you leave the transplant unit, your child will still have weak immune system and will be less able to fight infections. Some infections can be life-threatening. After discharge, your child will need a caregiver at home with them until their immune systems return to normal, a process that can take from a few months to a year.


Reviewed: August 2022