A bone marrow transplant (BMT) is a procedure that replaces unhealthy bone marrow with healthy stem cells. It's used to treat certain cancers, blood disorders, and autoimmune diseases. 

The process involves preparing the patient by reviewing medical history, conducting a physical exam, performing tests, and inserting a central venous catheter. Stem cells are then collected from the patient or a donor, filtered to remove abnormal cells, and infused into the patient through an intravenous catheter.

The critical time after a bone marrow transplant generally occurs within the first 100 days. This period is crucial due to several factors:

• Engraftment is the process where the transplanted stem cells begin to produce new blood cells. It typically takes 2-3 weeks. During this time, the patient's immune system is severely weakened, making them highly susceptible to infections.   
• Graft-versus-host disease (GVHD) is a serious complication that arises when the donor's immune cells attack the recipient's tissues. The risk of GVHD is highest in the initial months following the transplant, particularly within the first 100 days.   
• Other Complications: Infections, bleeding, and organ damage are potential risks during this period.
• The weakened immune system makes the body vulnerable to various infections, while the conditioning regimen (chemotherapy or radiation) used to prepare the body for the transplant can have side effects.   

Close monitoring by the medical team is essential during these critical first 100 days. Regular checkups, blood tests, and other assessments help identify and manage potential complications promptly.

For more information visit the official site:: https://www.edhacare.com/treatments/organ-transplant/bone-marrow