A system for determining a change in position of an implanted medical device (IMD) within an implant pocket, the system comprising: an accelerometer configured to be implanted in a patient, the accelerometer configured to obtain accelerometer data along at least one axis; memory configured to store program instructions; one or more processors that, when executing the program instructions, are configured to: determine the patient is engaging in a determined activity over an activity period; obtain the accelerometer data during the activity period; identify postures of the patient and corresponding posture periods during the activity period based on the accelerometer data; determine a duration related to a non-standing posture identified from the postures identified; and identify a migration of the IMD within the implant pocket based on the duration of the non-standing posture exceeding a duration threshold, characterized in that the one or more processors are further configured to: determine the migration of the IMD within the implant pocket based on the accelerometer data; and suspend obtaining the accelerometer data when the migration exceeds a migration threshold. an accelerometer configured to be implanted in a patient, the accelerometer configured to obtain accelerometer data along at least one axis; memory configured to store program instructions; one or more processors that, when executing the program instructions, are configured to: determine the patient is engaging in a determined activity over an activity period; obtain the accelerometer data during the activity period; identify postures of the patient and corresponding posture periods during the activity period based on the accelerometer data; determine a duration related to a non-standing posture identified from the postures identified; and identify a migration of the IMD within the implant pocket based on the duration of the non-standing posture exceeding a duration threshold, characterized in that the one or more processors are further configured to: determine the migration of the IMD within the implant pocket based on the accelerometer data; and suspend obtaining the accelerometer data when the migration exceeds a migration threshold. determine the patient is engaging in a determined activity over an activity period; obtain the accelerometer data during the activity period; identify postures of the patient and corresponding posture periods during the activity period based on the accelerometer data; determine a duration related to a non-standing posture identified from the postures identified; and identify a migration of the IMD within the implant pocket based on the duration of the non-standing posture exceeding a duration threshold, characterized in that the one or more processors are further configured to: determine the migration of the IMD within the implant pocket based on the accelerometer data; and suspend obtaining the accelerometer data when the migration exceeds a migration threshold. determine the migration of the IMD within the implant pocket based on the accelerometer data; and suspend obtaining the accelerometer data when the migration exceeds a migration threshold. <EOS>