Endometriosis is a chronic condition affecting 25-50 % of women with infertility. It is characterized by the presence of endometrial tissue outside the uterus, typically affecting other organs in the pelvis. The diagnosis is made by surgical exploration of the pelvis, usually by laparoscopy. This disease is found in 30 – 80% of women with pelvic pain (ASRM, 2006).  Surgical diagnosis and treatment of endometriosis in women with infertility is effective in women with more extensive endometriosis; it is of questionable benefit in women with mild endometriosis.

Why does endometriosis cause infertility?

The mechanisms that cause infertility in women with endometriosis are varied and not scientifically proven. Endometriosis, particularly in its more advanced stages, is associated with pelvic scar tissue that can distort the ovaries and tubes thereby causing tubal dysfunction and/or blockage and negatively affecting egg release or pick-up by the fallopian tube.  Endometriosis my also affect the immune environment thereby impacting egg quality, embryo development and embryo implantation.

Endometriosis and IVF Success

A common question addressed is whether the presence of endometriosis has a significant effect on IVF success? Studies have reported mixed results but there may be a negative effect on egg number, fertilization rates, embryo development, implantation and pregnancy rates. Despite these negative effects, IVF is the treatment of choice, particularly in women with moderate to severe endometriosis who have not responded to other treatment options.

Some studies have proposed the use of medications that suppress the adverse inflammatory effects of endometriosis as part of the IVF process, such as gonadotropin releasing hormone agonist (GnRHa).  Improved outcomes and success have been noted when suppression with a GnRHa is used for an extended period prior to ovarian stimulation.

What if I have Endometrioma(s)?

Another common question is whether cysts associated with endometriosis (endometriomas) affect IVF outcomes?  Although controversial, study outcomes have been mixed. It is recommended that endometriomas less than 3-4 cm not associated with pelvic pain should be treated non-surgically if possible as surgical removal can compromise ovarian reserve. On the other hand, large endometriomas can impact the ability for the ovary to produce adequate egg numbers thereby making it difficult for egg retrieval (Oxford University Press, 2008). There is also the associated risk of rupturing the cyst if inadvertently punctured during the egg retrieval. Factors that should be considered for endometrioma surgical resection include size of the cyst, whether there is pelvic pain, age, and history of previous cyst removal.