Precocious puberty runs in my family and we have had numerous young girls in the family on Lupron. They are closely monitored by a pediatric endocrinologist at a children's specialist hospital and they have repeated scans to assess for bone age and density. In most cases, they are on it for up to 3-4 years, going off at about 10-11 to allow them to them go through puberty at a typical age.
Given it is the effects of the drug being monitored and not the cause, I wonder why a similar level of precaution is not being taken for youth who used it for reasons other than precocious puberty (aka gender dysphoria).