The role of add-back therapy in the United States

Gonadotropin-releasing hormone (GnRH) agonists are effective in reducing pelvic pain due to endometriosis, but they are associated with a number of hypoestrogenic side effects, such as vasomotor symptoms and loss of bone mineral density. Add-back therapy with a progestin or a progestin plus low-dose estrogen helps to reduce the side effects associated with GnRH agonist administration without compromising efficacy. Add-back therapy should be initiated at the same time as the treatment with a GnRH agonist and longer-term therapy beyond 6 months can be considered in patients meeting the appropriate criteria.