There are many reasons that may cause grafted hair to fall out after transplant is done. One of the most common reason could be that the hair might be taken from a donor area that was not immune to male pattern baldness. This is unlikely if an experienced surgeon/technician perfomed the procedure. Another reason of losing the hair may be the grafted follicles. Doctors always suggest that a patient use Rogain 5% plus finasteride to diminish this possiblility. You may have some metabolic imbalance, such as hypo or hyperthyroidism.