Miss Chen, 29 years old, married for two years, has been trying to conceive without using contraception. However, she has not been successful in getting pregnant. She experiences severe menstrual pain each month, requiring pain relief medication and even visits to the hospital. Her employer has expressed concerns about her frequent leave due to menstrual issues. During a pelvic examination, irregular protrusions were found in the posterior cul-de-sac of the uterus. Additionally, her CA-125 blood test results showed a level of 86 U/ml. The diagnosis is endometriosis. What is endometriosis, and can it cause infertility?

 

Endometriosis, in simple terms, refers to the condition where the endometrium (the lining of the uterus) grows in places where it shouldn't, outside the uterine cavity. This abnormal growth of endometrial tissue in locations beyond the uterine cavity is known as endometriosis. Approximately 10-15% of the population experiences infertility issues, and among patients with endometriosis, around 30-40% face challenges with infertility.

 

As for the reasons behind the development of endometriosis, several hypotheses have been proposed and accepted. One hypothesis is retrograde menstruation, where menstrual blood flows backward into the fallopian tubes and pelvic cavity. Another hypothesis suggests the transfer of endometrial cells through blood or lymphatic circulation. The third hypothesis suggests remnants of embryonic cells that undergo migration and transformation. Regardless of the cause, endometriosis can occur in various locations, including the ovaries, fallopian tubes, uterine muscle layer, peritoneum, outer layers of the intestines, and uterosacral ligaments. The symptoms experienced are often related to the specific sites of endometrial growth.

 

The most common symptoms observed in clinical practice are dysmenorrhea (painful periods), dyspareunia (pain during sexual intercourse, particularly with deep penetration in certain positions), and diarrhea, collectively known as the "3D symptoms." However, it is important to note that the perception of pain varies among individuals, and the severity of endometriosis cannot be solely determined based on the level of pain. The presence of endometriosis can be indirectly inferred through the measurement of the tumor marker CA-125 in blood (typically ranging from 50 to 80 U/ml for endometriosis). However, this method is not entirely accurate. In terms of assessing the severity of endometriosis, apart from a pelvic examination, laparoscopic exploration is considered the most accurate. However, due to the diverse morphological characteristics of endometriosis, which can be likened to a chameleon, only experienced physicians can provide an accurate diagnosis. As for ultrasound, it is unable to detect signs of intra-abdominal endometriosis, except for chocolate cysts on the ovaries and adenomyomas in the uterus.

 

According to the definition provided by the American Society for Reproductive Medicine, endometriosis is classified into four stages: minimal, mild, moderate, and severe. In cases of moderate to severe endometriosis, there is often concurrent adhesion and obstruction of the ovaries and fallopian tubes, leading to a decrease in fertility. Therefore, doctors need to consider clinical symptoms alongside diagnostic examinations. If there is a strong suspicion of endometriosis, a laparoscopic examination is typically recommended. Once signs are detected, immediate intervention can be performed, including the restoration of fallopian tube patency. After careful laparoscopic surgery, pregnancy rates of over 50% can be achieved.