However, it is very important to realize there is no one type of pelvic or abdominal pain in women with endo. Women with endo report a wide variety of types of pain and timing of pain. There is really no "typical" endometriosis pain and it can occur at any time throughout the cycle.

Recent evidence links these painful periods to the increased levels of prostaglandins produced by the inflammatory response that forms around endometrial implants. Prostaglandins are naturally occurring substances in the body and cause contractions of uterine muscle.

Some women with severe endo will have no pain at all. Their endo will be diagnosed either in the course of investigation for infertility, or surgery for other reasons, or even during routine pelvic examination. The location is one important factor determining how much pain and what type of pain will occur. A small endometrial implant in a sensitive area such as on the supporting ligaments of the uterus, or in the pockets between the uterus and the large bowel may cause a lot of pain whereas extensive involvement of the ovaries may cause no pain at all. The depth of the endometrial implant is also a critical factor in determining how much pain will be felt.

Another common symptom of endo is pain during sex or at ovulation. Some women have more pain at ovulation than during their menses. Some women have pain between ovulation and their period. The pain during sex is usually felt deep inside, can be localized to one area of the pelvis; is worse after vigorous or deep thrusting and premenstrually; and often persists for hours after sex.

The type of pain can give you a clue as to where the endometrial implant might be located. If the large bowel is involved, painful bowel movements can occur on a cyclical basis once a month at the time of the period. If the bladder is involved, there may be painful urination and blood in the urine once a month at the time of the period or just before. If the ovaries are extensively involved, there may be spotting between periods, excessive menstrual bleeding or irregular menstrual cycles. Most often, however, even women with severe endo, continue to have regular periods until the periods stop altogether at menopause. If the pelvic ligaments are involved, there may be painful swellings that occur once a month in the groin area.

Rarely, leakage or rupture of large endometrial cysts at or before a period can cause severe abdominal pain that mimics appendicitis. The leaked or spilled blood products can then cause chemical irritation of the lining of the abdominal cavity. This serious emergency usually means immediate surgery to find the source of the pain, and treat it.

Women with endo have a higher rate of miscarriage and pregnancies in the tubes. The rate of miscarriage may be as high as 40 percent of pregnancies with the presence of endo. In fact, sometimes the initial reason that a women sees her doctor is for the investigation of infertility. The infertility can either be the type where the woman has never had a child or the type where a woman has had one child and then no subsequent pregnancies after five or more years without the use of any birth control.

How or why the tissue mis-location occurs in the first place is still a mystery. Many theories have been advanced to explain the cause of endo. One theory proposes that blood and tissue flow backwards out of the fallopian tubes and into the pelvic cavity and onto some organ or ligament. Bleeding from these implants then causes pain and other symptoms.

Diagnosing Endo

A doctor may be alerted to the possibility of endometriosis through a pelvic exam. The doctor may be able to feel a cyst on the ovaries or small lumps or nodules on the ligaments supporting the uterus or just behind the uterus. However, a laparoscopy is necessary to establish a definite diagnosis.

This is a minor operation done under general anesthetic. The doctor inserts a slender light-containing telescope into the abdomen to look at the pelvic organs and sometimes to perform minor surgery. At the time of laparoscopy, a small sample of the endometrial implants is taken and sent to the lab for microscopic examination. This biopsy will confirm the diagnosis.

Ultrasound examination is another useful diagnostic tool but it can not make the diagnosis definitely. It gives an idea of the extent of the endo, or the size of ovarian cysts. It's normally done prior to laparoscopy. However, the appearance of endo on ultrasound pictures is not specific enough to distinguish it from other types of pelvic growths.