Lack of agreement about the causes of endometriosis leaves a wide range of areas for research. Scientists continue to investigate the cause of the condition and potential areas of improved diagnosis and treatment. Some subjects of ongoing research include:

• Hormone-related therapy. Many of the studies for endometriosis treatment involve hormones, hormonal receptors and drugs that affect hormones. Some of these include:
  
  
• Selective estrogen receptor modulators (SERMs). These drugs act like estrogen in some tissues but like estrogen blockers in others. Animal studies involving specific SERMs have shown decreased lesion size. However, tamoxifen, a SERM used in breast cancer patients, may worsen endometriosis. Drugs that block progesterone in a similar manner (selective progesterone receptor modifiers, or SPRMs) are also being developed and studied.
  
  
• Gonadotrophin releasing hormone (GnRH) antagonists. These drugs are designed to be more effective against endometriosis symptoms than GnRH agonists, without many of the side effects.
  
  
• Aromatase inhibitors. Aromatase is an enzyme that helps produce estrogen in postmenopausal women. Some women with endometriosis have abnormal aromatase levels. One study of an aromatase inhibitor showed successful treatment of endometriosis in postmenopausal women. Clinical trials are being conducted among younger women. Aromatase inhibitors cause bone loss, which complicates their use.
  
  
• Mifepristone (RU-486). Some researchers are studying the use of this antiprogestin drug, which affects both progesterone and estrogen. It has been shown to block the effects of natural progesterone and improves endometriosis symptoms and reduces implants. The drug is licensed in the United States to induce abortions by causing a miscarriage. Some other antiprogestins are also being studied.
  
  
• Photodynamic therapy. Trials using this therapy involve intravenous (into a vein) injection of a dye concentrated in areas of endometriosis. A laser produces a photochemical reaction to destroy the lesions.
  
  
• Immune system. Some women with endometriosis have other conditions related to impaired immune function, such as lupus. Certain types of immune cells may be impaired in women with endometriosis. Some studies are under way about the immune response to endometriosis.
  
  
• Endometriosis markers. Researchers are investigating substances that could indicate the presence of endometriosis through a blood test or urine test. This would enable physicians to diagnose the condition without surgery.
  
  
• Guidelines. A study group of researchers, clinicians and patient representatives based in the European Society of Human Reproduction and Embryology (ESHRE) is devising guidelines for the diagnosis and treatment of endometriosis.