Endometriosis is a common gynecological disorder. Normally, the endometrium grows on the inner wall of the uterus to prepare the embryo for pregnancy, and if there is no pregnancy, the endometrium sheds and bleeds to have monthly menstruation. For various reasons, the endometrium grows outside the uterine cavity and endometriosis is formed. How close is the relationship between endometriosis and infertility? About 30%-58% of infertility patients have endometriosis in combination with endometriosis, and the incidence of infertility in patients with endometriosis is 30%-50%. Strathy et al. reported that the incidence of infertility in people with endometriosis is 20 times higher than in people without endometriosis. Endometriosis is known as the “invisible killer” of infertility in women of childbearing age. Ovarian chocolate cysts are also a type of endometriosis Often patients who have undergone surgery for ovarian chocolate cysts are surprised when I tell them that you are also suffering from endometriosis. After the endometrium is implanted into the ovary, in addition to purple-brown spots and vesicles that can appear on the surface of the ovary and in its cortex, single or multiple cysts, known as endometriotic cysts, can also form in the ectopic tissue in the ovary because of repeated bleeding during menstruation that cannot be discharged. Because the cysts contain dark brown mucousy old blood that resembles melted chocolate, they are generally referred to as “chocolate cysts”. How does endometriosis cause infertility? 1. Changes in the normal structure of the pelvis and abnormal function of the fallopian tubes: adhesions and fibrosis caused by endometriosis lesions can distort, stiffen and stiffen the fallopian tubes, and cause pathological changes in the umbrella of the fallopian tubes, affecting their functions of egg collection and transporting sperm and fertilized eggs, and adhesions around the ovaries can also affect ovulation. 2. Abnormal immune function and autoimmune reaction: the number and activity of macrophages in the peritoneal fluid of patients with endometriosis increase, and the phagocytosis of sperm is hyperactive; the ectopic endometrium is recognized as a foreign body by the immune system of the body, which activates the immune system of the body, generating antigenic and antibody reactions, activating the complement system, and increasing the secretion of cytokines. The ectopic endometrium is recognized as a “foreign body” by the body’s immune system, activating the body’s immune system, generating antigenic and antibody reactions, activating the complement system, and increasing cytokine secretion; the damage caused by various cytokines and the complement system interferes with oocyte fertilization, affecting fertilized egg division, transport and implantation, and producing toxic effects on fertilized eggs; the increase in prostaglandins in the peritoneal fluid can affect ovulation, corpus luteum function and oviductal movement, and also make the endometrium and fertilized eggs develop out of sync, affecting fertilized egg implantation. 3. Abnormal ovarian function: elevated prostaglandins in the peritoneal fluid affect follicular development and ovulation; decreased number of LH receptors in the ovary and luteal cells, resulting in insufficient luteal secretion; luteinized unruptured follicle syndrome (LUFS), which manifests as mature follicles but no ovulation and luteinized follicular cells. Although the basal body temperature is biphasic and the endometrium is in secretory phase, there is no possibility of conception. 18%-79% of patients have LUFS in combination; ectopic endometrial tissue invades and destroys ovarian tissue; surgical debridement of the lesion, especially the destruction of ovarian reserve function by thermal injury during electrocoagulation; large cysts compress and affect the blood flow of the ovary, which decreases the ovarian response to gonadotropins. 4.In-situ endometrial defects reduce endometrial tolerance: changes in endometrial morphology in patients with endometriosis, including: irregular distribution of glandular number and glandular cavity, poorly developed glandular cells; incomplete regeneration and poorly developed cilia of ciliated cells; reduced convexity of cytosolic drinking. 5. Some domestic scholars also believe that the decrease in the frequency of sex and the change in sexual lifestyle due to endometriosis pain may also cause the decrease in female conception rate. How to deal with endometriosis? Patients with fertility requirements should have a preoperative fertility test for both spouses before developing a treatment plan. (1) For those with fair ovarian reserve function, surgical treatment can be performed according to the guidelines (the 2015 endometriosis guideline specifies the indication for surgery for cyst size as ≥100px) and pregnancy as soon as possible after surgery. (2) For those with poor ovarian reserve, egg retrieval for assisted reproduction is recommended first. If the cyst is too large or interferes with egg retrieval, colectomy is feasible. What are the advantages of endometriosis treatment in Shanghai Jiu Hospital’s Assisted Reproduction Department? Among the traditional assisted reproduction techniques for endometriosis, GnRHa down-regulation protocol is commonly used to press the patient’s hormones to the lowest level, with obvious menopausal symptoms and a series of side effects of low estrogen and low efficiency of ovulation promotion. The Department of Assisted Reproduction of Shanghai Jiu Hospital adopts a unique technique for patients with endometriosis to improve the intrapelvic environment of patients with endometriosis, which improves the success rate of embryo transfer to low cost. The low number of visits has attracted endometriosis patients from all over the country.