Causes of Infertility- Endometriosis

Endometriosis is present in 6-10% of women in the general population, it is a factor of infertility in about 38-50% women trying to get pregnant and it is the main cause in 70-87% of women with chronic pelvic pain.

Endometriosis occurs when the cells that normally line the uterus (endometrium) enter the pelvic and abdominal cavity and attach to other organs found in them. These endometrial implants can grow and damage the structures they are attached to thus leading to organ dysfunction. These endometrial cells, which have receptors to both estrogen and progesterone, will become implanted in organs and structures outside of the uterus, where these hormonal activities continue to occur causing bleeding and scarring. These implants can be located in the peritoneum, ovaries, around the fallopian tubes, the gastrointestinal tract (12-37%), around the bladder (20%), and less commonly the vagina. Endometriosis is often found on the Fallopian tubes and it can penetrate and obstruct these delicate structures.

Endometrial implants vary widely in size, shape, and color. They may be colorless, red or very dark brown. These so called chocolate cysts are called endometriomas filled with thick, old, dark brown blood and are located inside the ovaries.

Monthly hormonal changes cause these implants to grow; when the endometrium sheds and bleeding occurs, so do they, producing inflammation and inviting pain-causing chemicals. Many theories about the cause of endometriosis, focus on the possibility that endometriosis represents a state of an impaired immune system, which allows the endometrial implants to invade and proliferate. Biopsies of endometriosis will contain large levels of macrophages, which include cytokines and prostaglandins. These factors will produce inflammation and damage the surrounding tissues and cells.

It is speculated that endometriosis has a genetic link as there is a 10 fold increase in the incidence of endometriosis in women who have a mother or a sister with this disorder.

Endometriosis Symptoms

Many women may not have any symptoms. When symptoms are present the most common ones include severe cramps during menstruation. Pelvic pain can occur at any time and may last for a long time and can radiate to the lower back, pain during, or after intercourse, or when inserting and removing tampons, painful urination or bowel movements and other symptoms.

Endometriosis and Infertility

Several theories as to how endometriosis affects fertility include:

Endometrial implants may affect the fallopian tubes blocking the passage of the egg
Implants in the ovaries can prevent the release of an egg
Endometriosis can cause adhesions to form between the uterus and ovaries, and the fallopian tubes, thus preventing ovulation
Endometriosis can lead to decreased egg quality causing diminished ovarian reserve
The inflammatory cytokines produced by endometriosis create a hostile environment to sperm, fertilization and implantation

Diagnosis and Treatment

The laparoscopy is the only accepted method used to diagnose endometriosis. This procedure requires general anesthesia. The surgeon makes a small incision in the umbilicus and lower pelvis and carbon dioxide is injected to distend the abdomen. Then a small camera is inserted to view the uterus, tubes and ovaries.

Treatment

Hormonal therapy- these include oral contraceptives, GnRH agonists, and progestin. They may be given continuously in order to stop the menstrual cycle for a period of time in which the endometrium implants cause of endometriosis regress and almost disappear.

Danazol- this drug “tells” the brain to stop signaling the ovaries to release an egg, thus shutting down the menstrual cycle and thinning the endometrium and implants.

GnRH- This medication, given as a nasal spray or an injection, causes a temporary menopause-like state. The uterine lining will thin and menstruation will typically cease. The treatment is used for 3-6 months and when stopped, symptoms may return.

Treating Infertility in Patients with Endometriosis

In women with mild to stage I to II endometriosis, ovulation induction using Clomid, letrozole or gonadotropins in combination with intrauterine insemination (IUI) may be sufficient to induce pregnancy. For women with moderate to severe endometriosis conservative surgery (laparoscopy) may be helpful in restoring fertility. The use of GnRH post laparoscopy seems to only delay conception and may not be beneficial in improving pregnancy rates.