Treatment of endometriosis-associated subfertility (difficulty conceiving)
Endometriosis is more common in women with infertility and between 30-50% of women with endometriosis may have difficulty conceiving. In moderate and severe endometriosis the scar tissue and adhesions around the tubes and ovaries may be expected to cause subfertility as a result of distorted pelvic anatomy. Less severe endometriosis, in the absence of any obvious damage to the tubes and ovaries may also cause subfertility although the reasons for this are less clear. Possible reasons include subtle defects in ovarian function, ineffective transport of the sperm and egg and altered immune function.
If a woman with endometriosis has difficulty becoming pregnant then surgical treatment should be considered. Medical treatment with hormones has no role in the management of subfertility (with the exception of some women undergoing IVF, see In vitro fertilization), and will actually delay the opportunity to become pregnant for the duration of treatment. Expectant management (doing nothing) is often used to good effect, however the duration of subfertility and severity of endometriosis should be considered when deciding on expectant management. Prior to surgery other potential causes for subfertility should be identified, such as problems with ovulation or sperm. If other causes are also present the recommended management approach may be different.
Hormonal treatment for subfertility
There is no evidence to support the use of hormonal treatments in endometriosis to improve subfertility. Most of the hormonal treatments also act as contraceptives. Therefore hormonal treatment should not be used for women trying to conceive naturally as they are not effective and they may delay the use of more effective treatments such as surgery or assisted reproductive techniques.
Surgical treatment for subfertility
There is evidence to show that surgical treatment may improve fertility rates in women with minimal and mild endometriosis. There is insufficient evidence to determine whether surgical treatment of moderate and severe endometriosis enhances pregnancy rates and subfertility rates tend to be higher in women with more severe disease. Any decision for surgery to improve fertility should be made after careful assessment and discussion between the woman and the specialist. Ovarian cysts (endometriomas) should be treated by laparoscopic cystectomy (excision of the cyst) where possible, rather than simply drainage of the fluid from the cyst, as excision is associated with higher pregnancy rates than drainage. There is no role for post operative treatment with hormone therapy following surgery as this has not been shown to improve fertility.
Wherever possible, depending upon the individual’s situation, surgical treatment to improve fertility should be laparoscopic rather than at laparotomy. Laparoscopic surgery offers the advantages of shorter hospital stay and recovery time, better visualization at surgery, less tissue trauma, fewer postoperative adhesions and scar tissue with equivalent or better post operative pregnancy rates.
Assisted reproductive techniques (ART) and endometriosis
Some women with endometriosis may require assisted reproductive techniques (ART) such as intrauterine insemination (IUI) or in vitro fertilization (IVF) to treat infertility. Assisted reproductive techniques are methods which bring the sperm and egg closer together, increasing the chances of fertilization and ultimately a pregnancy resulting in the birth of a baby.
Assisted reproductive technology is an effective means of achieving pregnancy for many women with endometriosis-associated subfertility. These should be carried out in specialist clinics.
The effect of assisted reproductive techniques on the recurrence rate or progression of existing endometriosis has not been widely studied however such treatments are often recommended for couples with endometriosis-associated subfertility.
Intrauterine insemination (IUI)
IUI involves placing prepared sperm directly into the uterus at the time of ovulation. Ovulation may occur naturally or can be induced with drugs (ovarian stimulation). In most cases it is recommended that women with endometriosis requiring IUI undergo ovarian stimulation to induce ovulation. Women with mild to moderate endometriosis can be treated with IUI provided that the fallopian tubes are open and free of adhesions and there are sufficient numbers of healthy sperm.
IUI is not usually suitable for women with severe endometriosis as is necessary for the pelvis to be as structurally normal as possible.
In vitro fertilization (IVF)
In vitro fertilization involves stimulating the ovaries to produce lots of eggs, collecting the eggs from the ovaries under ultrasound control and fertilizing them with the partner’s sperm in a laboratory. Fertilized eggs (embryos) are then placed in the uterus. IVF may be recommended in endometriosis-associated subfertility if there is severe disease, accompanying problems with the sperm, or if other treatments have failed. The success rate for each cycle of IVF will vary according to individual factors such as the woman’s age, but the pregnancy rate for each cycle may be up to 25%.
Ovarian cysts (endometriomas) which are 4cm in diameter or larger should be removed surgically by laparoscopic ovarian cystectomy (see surgical treatment of ovarian cysts). Removal of such endometriomas may increase the success rate of IVF; it almost certainly reduces the risk of infection during the egg collection procedure, which can occur if any endometrioma is accidentally punctured by the needle used to collect the eggs.
In some cases treatment with a GnRH analogue (see ‘Gonadotrophin Releasing Hormone Analogues) for 3 to 6 months before IVF may be recommended, especially for women with severe disease. Although limited, the available evidence suggests that such pre-treatment is associated with higher rates of clinical pregnancy for IVF cycles than women not treated with GnRH analogues.