Endometriosis affects up to 10% of reproductive age of women. Endometriosis is associated with infertility. At least one third of women with endometriosis have infertility. Women with infertility are 6-8 times more likely to have endometriosis. Some women with endometriosis will conceive without difficulty, while others may have difficulty to conceive. Some controlled trial study showed that women with endometriosis were 10% less likely to conceive than those without the condition. The pregnancy success rate among women with endometriosis associated infertility was lower than those with unexplained infertility. A study of 14 randomised controlled trials showed that women with endometriosis were less likely than women with tubal-factor infertility to conceive by means of IVF. Endometriosis is also associated to lower live birth rate.
The mechanisms of association between endometriosis and infertility are not fully understood. Moderate to severe cases can lead to infertility. The connection between severe endometriosis and infertility is due to severe pelvic adhesions which cause a variety of anatomical abnormalities. This can affect ovum capture and transport. The severe ectopic endometrial lesions is also decreasing implantation rates, decreasing egg retrieval rates and decreasing pregnancy rates.
Most of endometriosis cases are mild. Some women with mild endometriosis have also had infertility and many women with infertility have had mild endometriosis. The cause and effect relationships between mild endometriosis and infertility are not clear. Severe endometriosis can cause reproductive organs scarring and distortion. The association of minimal and mild endometriosis with infertility is also possible. This is because endometriosis causes ovulatory dysfunction, impaired follicle development, defective implantation, eutopic endometrium abnormalities, abnormal immunological environment and luteal phase problems. Luiz Fernando et al collected the data from 1985 -2011 to investigate the association between mild endometriosis and infertility. They found there were two randomized controlled trials for this study. In 1997 Marcoux et al conduceted a randomized controlled trial studied the association between endometriosis and pregnancy rates. They compared pregnancy rates in 172 women with stage I and II endometriosis who underwent laparoscopic removing all visible endometrial lesions with 169 women who underwent diagnostic laparoscopy only. All women were followed postoperatively for 36 weeks. The cumulative pregnancy probability rate for the surgery group was 30.7% while pregnancy rate for the diagnostic group was 17.7%. This result showed significant differences between two groups indicating the association of mild endometriosis and infertility. This suggestion was supported by another study. The conclusion is that minimal to mild stages of endometriosis plays an important role related to infertility and has negative impact on pregnancy rate.
In summary, the association between endometriosis and infertility may be caused a few mechanisms.
Distorted pelvic anatomy: endometriosis could cause pelvic adhesions. These organs can adhere to the uterus, bowel or pelvic wall. This distortion of reproductive organs could cause infertility. if the eggs in the ovaries are damaged by the misplaced tissues egg quantity and quality could be compromised which results ovulation abnormalities which can impair egg release from the ovary and egg pickup after being released; The tubes can be damaged and blocked; ovaries can contain cysts formed from misplaced tissue it also can block sperm entry into the distal tube.
Altered peritoneal environment: Also Altered peritoneal function and impaired endometrium and implantation are also contributing to the infertility. women with endometriosis have increased volume of peritoneal fluid, increased immune cells and concentrations of prostaglandin etc. These may impair egg, sperm, embryo and fallopian tube function.
Altered system immune function: women with endometriosis may have increased antibodies and lymphocytes and this may alter endometrial acceptance to embryo implantation.
Endocrine and ovulatory abnormalities: Women with endometriosis may also present abnormal follicle growth, the luteinized unruptured follicle syndrome, luteal phase dysfunction and premature and multiple LH surges.
Abnormal tubal function: egg capture inhibitor was reported present in peritoneal fluid from women with endometriosis.
Abnormal fertilization and implantation: fertilization and implantation may be impaired in women with endometriosis. Endometrial function may be not normal.
Medications could improve the quality of life for many women with endometriosis; however their contraceptive effects are limited their application. There were many researches showing that acupuncture is effective of releasing pain associated with endometriosis. Acupuncture also stops misplaced tissue growing, regulates period and improves fertility. According to traditional Chinese medicine theory, endometriosis is caused by blood stagnation. Acupuncture improves blood flow; this will release the pain and improve other symptoms.
There was a case report about acupuncture treatment for endometriosis associated infertility from China. 25 patients with endometriosis associated with infertility were treated with acupuncture. After 2 months of treatment, 9 patients achieved pregnancy.
A report in Zhong Guo Zhen Jiu (1996) also studied effectiveness of acupuncture on endometriosis associated with infertility. There were 72 women with endometriosis associated with infertility involved. The acupuncture treatment duration is 3-9 month. 42 women achieved pregnancy. Success rate was 58.33%.
Zhou et al (2009) Afr J Tradit Complement Altern Med 6: 494-517
Luiz Fernando et al Rev Assoc Med Bras (2012) 58:607-614