Endometriosis (“endometriosis”) seriously affects the health and quality of life of young and middle-aged women. In recent years, studies have found that endometriosis is the cause of about 30% of infertility patients.At the Peking University Gynecology and Obstetrics International Forum in April 2015, Associate Professor Xue Qing from the Department of Obstetrics and Gynecology of Peking University First Hospital introduced the relationship between endometriosis and infertility and the treatment recommendations in the context of clinical practice, and a reporter interviewed her on the subject after the meeting. The relationship between endometriosis and infertility When the endometrium that grows in the uterine cavity grows in a part of the uterine cavity other than the mucous membrane that coats it, it is called endometriosis (referred to as “endometriosis”). The endometrium is often located in the pelvic peritoneum, ovaries, uterosacral ligaments, cesarean section surgery scars, etc. It is mainly seen in women of childbearing age. Endometriosis is a very common disease in gynecologic reproduction, with an incidence of about 15%. The main effects on women are pain and infertility. The initial diagnosis of endometriosis is made in women of childbearing age with progressive dysmenorrhea or/and a history of infertility, a tender hard nodule in the pelvic cavity or an inactive cystic mass next to the uterus on gynecologic examination. Ultrasound and nuclear magnetic resonance imaging (NMRI) can be used to examine patients with endometriotic cysts. Serum cancer antigen 125 (CA125) and cancer antigen 199 (CA199) are often mildly elevated in patients with endometriosis. Endometriosis seriously affects the health and quality of life of young and middle-aged women. 30% of patients are associated with varying degrees of infertility, and 50% have dysmenorrhea and lower abdominal pain, which may or may not be clinically manifested. The cause of infertility is endometriosis in about 30% of patients. In addition, patients often experience recurrent miscarriages. The relationship between endometriosis and infertility can be explained by two thirds: one-third of patients with endometriosis have infertility problems; among the causes of infertility, endometriosis can account for up to about 30% of the proportion, i.e., one-third of infertile patients have endometriosis problems. The two are inextricably linked. Endometriosis affects infertility in several ways. It affects ovulation and corpus luteum function; causes pelvic adhesions, tubal distortion and obstruction; has a toxic effect on spermatozoa and embryos; and alters the body’s immune function and the environment of the uterine cavity, which is not conducive to embryo implantation. Treatment principle of infertility combined with endometriosis The treatment principle of infertility combined with endometriosis is early diagnosis and early treatment. Laparoscopy is the gold standard for diagnosing pelvic endometriosis. It is generally believed that for the first occurrence of ovarian ectopic cysts larger than 4cm (also known as chocolate cysts, or “coeliac cysts” for short), laparoscopic surgery should be performed first to reduce the risk of infection and improve the conditions for egg retrieval, followed by fertility treatments. In addition to the special location of ectopic disease and the difficulty of surgery, another characteristic is that it is easy to recur, with a recurrence rate of up to 10% per year. Ovarian coelomocysts are characterized by severe adhesion to the surrounding area after stripping. In almost all ovarian cyst removal surgeries, the coelomic sac has the greatest impact on ovarian function. It is impossible for a woman’s follicles to regenerate; the reserve of follicles is already determined at birth. After surgery for coelomocysts, ovarian function will decline prematurely, and in severe cases, even cause premature failure, even if there is no premature failure, ovarian function will still decline. If the patient needs assisted conception techniques, her fertility will be significantly reduced. Recurrence after surgery is a big clinical problem nowadays. Contraceptives are more economical medications, and patients can take oral contraceptives for a long time in the short term after surgery if they have no fertility requirements, not for contraception but to have an inhibitory effect on the disease and to avoid reoccurrence of ectopic disease. When fertility is desired, the pill can be stopped, and the patient can either be assisted in conceiving or conceive naturally. In the unfortunate event that recurrent endometriosis has already occurred, along with infertility problems, the patient is usually not advised to undergo further surgery unless there are very severe painful symptoms that would allow the removal of the lesions, otherwise the patient may be advised to fulfill the need for fertility first. If further surgery is performed, there will be another blow to the ovaries, making them function even worse. The patient can opt for a suitable fertility support method, such as some extra-long reduction and downgrading protocols for IVF, or ovulation induction, egg retrieval, and whole embryo freezing in the first place. If there is a very severe adenomyoma, better results may be obtained by treating it with pituitary down-regulating drugs first and then transferring the embryos after a few months. The pathogenesis of ectopic disease is unclear and there are many reasons for infertility, with varying opinions, some suggesting that it affects endothelial tolerance, while others have the doctrine that it affects the quality of the egg, and so on. There is still a lot to be developed and explored, especially in recurrent coeliac disease, which is a difficult subject in reproductive assisted conception. The patient has had one surgery, the ovarian function is relatively poor compared to other people, and at the same time there is a new coelomic sac growth, which also has an impact on the IVF process, such as easy to get infected during the egg retrieval process, the number of egg acquisition decreases, affecting the quality of the egg, poor quality of the embryo, and so on, and these are the directions we need to research, explore and develop in the future. Preparing for pregnancy as soon as possible after surgery Young and mildly ill patients are advised to prepare for pregnancy as soon as possible after surgery. You can have intercourse every three days, or ultrasound to monitor ovulation and guide the timing of intercourse. If you have been trying to conceive for 6-12 months and have not conceived, it is recommended that you seek the help of a fertility doctor. Women older than 35 years of age, or patients with severe medical conditions, are advised to consult a fertility doctor directly to determine which fertility-assisting technique will be used to improve the pregnancy rate, depending on the condition of the man’s semen and the condition of the woman’s fallopian tubes. For example, intrauterine insemination (IUI) or in vitro fertilization-embryo transfer (IVF-ET), commonly known as “test tube baby”. For infertile patients who have coeliac recurrence after coeliac surgery, IVF is recommended as the preferred treatment, which has a higher success rate than repeated surgeries. Young women who do not intend to get pregnant are advised to take the pill for a long time to delay recurrence if there are no contraindications.