Endometriosis and infertility
Surgery is more effective for infertility than medicinal intervention in endometriosis. One study has shown that surgical treatment of endometriosis approximately doubles the fecundity (pregnancy rate). The use of medical suppression after surgery for minimal/mild endometriosis has not shown benefits for patients with infertility. Use of fertility medication that stimulates ovulation (clomiphene citrate, gonadotropins) combined with intrauterine insemination (IUI) enhances fertility in these patients.
Endometrosis
Endometrosis is a chronic degenerative syndrome of the lining of the uterus (the endometrium) in mares. The cause is unknown, but the severity of endometrosis increases in parallel with the age and number of pregnancies of the mare. Endometrosis is confirmed by histological examination of an endometrial biopsy, which shows degeneration of blood vessels in the endometrium, and fibrosis of the tissue, along with the development of endometrial cysts. These changes cause subfertility; in pregnant mares, the changes in the endometrium can cause the placenta to fail, leading to miscarriage of the foal. Foals which are delivered at full term may be underdeveloped (dysmature). No effective treatment is known.