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Endometriosis glossary

This page contains a glossary of medical terms and words that you may read or hear when you are learning about endometriosis.




Abdominal hysterectomy A hysterectomy carried out through a cut in the abdominal wall. Learn more about hysterectomy.

Add-back When taking certain hormones, Gonadotropin releasing hormone agonists (GnRH agonists), that put the body into an artificial menopause, the side effects can include menopausal symptoms such as hot flushes, loss of libido, vaginal dryness, headaches, loss of concentration or mood swings. A serious ‘hidden’ side effect can be loss of bone density – which can lead to osteoporosis. To try to counteract these side effects, small doses of oestrogen/progestogen in the form of HRT, Livial, or Norethisterone are given at the same time. They replace some of the hormones that are removed by the hormone treatments.   

Adenomyosis  A disease where endometrial tissue grows in the muscle layer of the wall of the womb, bleeding and causing pain. This is not the same as endometriosis. 

Adhesion Fibrous scar tissue that is formed inside the body. They are usually caused by trauma to tissue – which can happen with endometriosis or because of an injury, or during surgery. They are a cause of pelvic pain. They can attach organs to each other inside the pelvis, or to the pelvic wall.

Anaesthetic  Induced loss of feeling and awareness in a patient. Anaesthetics can be either local or general. A general anesthetic puts the patient to sleep (makes them unconscious), a local anaesthetic will numb a part of the body.

Androgen  A hormone that stimulates or controls the development and maintenance of masculine characteristics. Testosterone is the most commonly known androgen. 

Anaemia A condition caused by heavy blood loss, excessive red blood cell destruction, or a deficiency in the production of red blood cells.  It causes a low red blood cell count, which leads to extreme tiredness. 

Aromatase inhibitors  Medication that stops (inhibits) the enzyme aromatase from working.  Aromatase changes androgens into oestrogen. These drugs are occasionally being used to treat women with endometriosis, if those women have not responded to other treatments. These drugs are used to treat some breast cancers. They are still in the experimental phase for the treatment of endometriosis.

Autoimmune Disorders  When immune cells attack the body’s own cells by mistake. Examples of autoimmune disorders include Type 1 diabetes mellitus, coeliac disease and rheumatoid arthritis.


Back pain Pain felt in the low or upper back. There are many causes of back pain.

Benign Something which is not life threatening or cancerous.  A benign tumor does not invade surrounding tissue or spread to other parts of the body. Benign tumours can cause problems if they are large, or obstruct the bowel or other organs. 

Biopsy The removal of a sample of tissue for purposes of diagnosis. During a laparoscopy, the doctor may biopsy some tissue from your body, to see if it has endometriosis or other diseases. The biopsy is examined a laboratory.

Bone density: The measurement of how strong (dense) a person’s bones are, in their body. If a person’s bones become weak, and lose bone density – this can lead to them becoming brittle and easily broken. This is a condition called osteoporosis.

Bowel The section of the digestive system that runs from the stomach to the rectum (anus). It is also known as the intestine. The small bowel and the large bowel are the small intestine and large intestine, respectively. The bowel works by digesting and then absorbing the nutrients form the food we eat, then by making stools (faeces/poo).

Bilateral salpingo-oophorectomy Surgery to removal both ovaries and fallopian tubes.

Bowel resection Surgery to remove a part of the bowel. The procedure may remove the portion of the bowel where an obstruction is located. Complications of a bowel resection include fistula, the formation of adhesions, and the possibility of a colostomy.


Carbon dioxide  A gas known as CO2, which is produced during the breathing process. During a laparoscopy, CO2 is pumped into the abdomen, to enlarge it, and move the wall of the abdomen away from the internal organs, to allow the surgeon room to get at them.

Cauterisation  The removal or destruction of tissue with a laser or an electrical current. This can help with heavy bleeding and removal of endometriosis deposits.

Cervix  The 'neck' of the womb or the opening between the body of the womb (uterus) and the vagina. 

Chocolate cyst (endometrioma)  A cyst in the ovary, filled with old blood, also known as an endometrioma. It occurs when there is bleeding into a cyst. They are called chocolate cysts because the blood is dark coloured and looks like liquid chocolate.

Chronic: Persistent and lasting a long time.

Chronic fatigue syndrome: Persistent, disabling fatigue (exhaustion) that affects every day life and doesn't go away with sleep or rest.

Cul-de-sac The area between the womb (uterus) and the rectum. It is also known as the Pouch of Douglas.

Cystoscopy A procedure where the bladder is examined using a small telescope inserted through the urethra (tube where urine passes from the bladder to outside the body).


Disease: Illness or sickness that usually has typical symptoms.

Dioxin a toxic chemical (compound) found in pesticides, the manufacturing and burning of paper and plastics, and food such as meat, diary produce and fish, etc. It may be linked to endometriosis, see our causes section.

D&C (Dilatation and Curettage)  A procedure, done under general anaesthetic, where a woman’s womb is dilated and then the lining of the womb is scraped with a spoon shaped instrument and removed (curettage).

Dysmenorrhea Painful periods.

Dyspareunia Painful sex.


Ectopic pregnancy When a fertilised egg stays in the fallopian tube and starts to develop, instead of travelling into the womb.  This can be dangerous and even life-threatening if left untreated.

Endometrial ablation When the womb lining is removed using a variety of methods including lasers, electric currents, being frozen or using heat. This treatment for heavy menstrual bleeding permanently stops periods and prevents future childbearing. 

Endometrial hyperplasia When the womb lining thickens and grows excessively. It is a benign or pre-malignant condition.

Endometrioma See chocolate cyst 


Fallopian tube A tube that lies between the ovary and the womb, and transports the eggs to the womb. A woman has two Fallopian tubes.

Fatigue Extreme tiredness. It can come on quickly, or be a chronic condition.

Fibroid (leiomyoma) A benign tumour of the uterus (womb).

Follicles Areas in the ovary, filled with fluid, containing the eggs that are released during ovulation. 

Follicle Stimulating Hormone – FSH One of the gonadotropins - the hormones that stimulate the growth of the follicle.


Gonadotropins The hormones that control the function of your ovaries. They are called the Follicle Stimulating Hormone (FSH) and the Luteinizing Hormone (LH). 

Gonadotropin Releasing Hormone – GnRH A hormone that controls the release of the gonadotropins (FSH and LH) from the pituitary gland.  

GnRH Analogue (Agonist) - gonadotropin releasing hormone analogue The GnRH analogues are drugs that induce an artificial, medical, reversible menopause in women, as they stop the ovaries from functioning.  

GnRH Agonists work by over-stimulating the release of the GnRH from the pituitary gland. This stops the FSH and LH from stimulating the ovaries and causing them to release eggs. This causes ovulation and periods to stop.  

These drugs may cause symptoms similar to that of the menopause and can also cause a reduction in bone density, eventually leading to osteoporosis. For these reasons, GnRH agonists are prescribed as a temporary measure (e.g. for 6 months) so that they help with symptoms. Please see our section on hormone treatment.

Gynaecologist  A doctor who specialises in female conditions – primarily the reproductive and urological (kidneys, bladder etc) organs. Your GP may refer you to a gynaecologist to investigate symptoms.


Hormone  A chemical substance released inside the body that controls and maintains the activity of cells or organs.

Hormone Replacement Therapy – HRT  Medication used to mimic the effects of oestrogen. It is prescribed after a hysterectomy or during menopause (either natural or medical) to counteract the effects of the menopause. Those effects include hot flushes, night seat, loss of libido, mood swings, loss of bone density and vaginal dryness.  HRT has its own risks and should be carefully considered before taking.

Hysterectomy  The removal of the womb from the body during surgery. There are several different ways this is done, see below:

  • Total hysterectomy: The removal of the womb (uterus) and the cervix, under anaesthetic.  
  • Sub-total hysterectomy: The removal of just the body of the womb (uterus).
  • Total hysterectomy with bilateral salpingo-oophorectomy: Removal of the womb (uterus), cervix, ovaries and fallopian tubes.  

Hysterectomy can be done with or without removing the ovaries. If the ovaries (or disease elsewhere) are left in place then endometriosis is likely to continue occurring. Some women then need a further operation to remove the ovaries later. Hysterectomy is not the right operation for everyone and not a decision to make lightly. Consider all options and discuss things fully with your GP or Gynaecologist. Remember that a hysterectomy is irreversible. Hysterectomy can treat adenomyosis effectively and is an effective treatment for endometriosis if all the remaining deposits of the disease (which can be hard to find) are removed along with the ovaries.

Hysteroscopy  A procedure in which the doctor examines the inside of the womb (uterus) under anaesthetic, by inserting an instrument (hysteroscope) into the womb. Minor surgery, such as the removal of a polyp, can be done at the same time.


Immune system The system within the body that secures against harmful substances; it enables the body to recognise materials as foreign to itself and to neutralise, eliminate, or metabolise them with or without injure to 

Incision A cut made into the body, by a doctor during a surgical procedure.

In Vitro Fertilisation (IVF) Literally means "in glass." Fertilisation takes place outside the body in a small glass dish. 

Infertility The inability to become pregnant; if a couple has a year of regular, unprotected sex and doesn’t become pregnant, then that is also classed as infertility.   
            Primary infertility is difficulty in conceiving for the first time.  
            Secondary infertility is difficulty in conceiving after already having been pregnant.  
            Unexplained infertility is difficulty in conceiving that cannot be explained by a particular          cause or reason.
Infertility should be investigated by a doctor and can be treatable, through surgery or through taking hormones, or trying for a baby using In-Vitro-Fertilization (IVF). These methods are not always successful.

Inflammation A way in which the body reacts to infection, irritation or other injuries. Inflammation causes swelling and pain. With endometriosis, inflammation is caused by the release of hormones called prostaglandins. 

Informed consent A contractual agreement between a healthcare professional and a patient, where the patient understand and agrees to any treatment or surgery and the implications and risks involved and what it is trying to achieve. This agreement should be based upon clear and accurate information being provided to them by the healthcare professional.

Internal exam Also known as a vaginal examination. The patient lies on a couch and sometimes the feet are put in stirrups. The doctor or nurse then inserts fingers into the vagina and also presses on the abdomen to feel the pelvic organs. The patient and the doctor/nurse both have a right to a chaperone for this examination. 

Intrauterine Inside the womb (uterus), the opposite of extrauterine - outside the womb.

IUCD (Intrauterine Device)  A device placed into the womb to prevent pregnancy.

Irritable bowel syndrome (IBS)  A disorder of the bowel disorder causing bloating, cramps, spasm, constipation and diarrhoea.






Laparoscope: An instrument, like a small telescope with a light on one end, used to look at the inside of the pelvis, during a laparoscopy. 

Leiomyoma The medical term for fibroids. 

Lesion A small area of abnormal tissue – can be caused by endometriosis, other diseases or injury.

Luteal phase The part of the menstrual cycle between ovulation and menstruation

Luteinising hormone (LH) One of the gonadotropins - the hormone that is responsible for releasing an egg.

Laparoscopy  The only way to diagnose endometriosis is through a procedure called a laparoscopy.  Usually done under general anaesthetic, a small telescope with a light on the end (the laparoscope) is inserted into the pelvis through the navel (belly button). The laparoscope usually has a camera to transmit the images to a video monitor, which the surgeon uses to look inside the body. Carbon dioxide gas is used to extend the abdomen, to give the surgeon room to see the organs. The surgeon can move the laparoscope around the abdomen, to look for endometriosis. They may make another small cut to insert surgical instruments to treat the endometriosis or they might remove part of it to be examined at a later stage, this is known as a biopsy. After the procedure, the gas is removed.  


Menopause When a woman’s ovaries stop functioning and her periods stop. This can either be artificially induced through drugs or a hysterectomy, or happen naturally.

Menorrhagia Heavy periods. 

Menstruation The monthly cycle where the body prepares for pregnancy. Every month a woman’s body goes through hormonal changes. Hormones are naturally released which cause the lining of the womb to increase in preparation for a fertilized egg. If pregnancy does not occur, this lining will break down and bleed – this is then released from the body as a period.  

Miscarriage Spontaneous loss of a foetus from the womb.


Nausea Feeling sick or queasy and needing to vomit.

Navel The belly button, otherwise known as the umbilicus.

Neurectomy The removal of a nerve, can be done to help relieve pain. 

Neuropathic pain  Pain caused by damage to the nervous system, which affects its ability to perceive pain. This pain is usually chronic and lasts longer than the time taken for damaged tissue to heal. It can be treated with pain modifiers such as anti-depressants or anti-convulsants. Please see our pain relief section for more details.

NSAIDs such as Ibuprofen, Voltarol and Ponstan (mefanemic acid) block the production of prostaglandins in the body. Prostaglandins occur naturally, in response to injury or disease, and cause pain and inflammation. They have a number of functions including making the womb contract during a period (which helps with the shedding of the womb lining). These contractions can cause pain. It is thought that women with endometriosis may produce more prostaglandins than women without the condition.


Obstetrician A doctor who specialises in delivering babies and monitoring pregnancies.

Obstruction When something is blocked (obstructed) e.g. the bowel.

Oestrogen  The female sex hormone produced in the ovary. It is produced in response to hormones (FSH and LH) released from the pituitary gland and controls the female sex characteristics, e.g. breasts. It is responsible for the growth of womb lining. 

Oligomenorrhea Infrequent periods

Oophorectomy The removal of one or both of the ovaries. When both ovaries are removed, the surgical procedure is called “bilateral oophorectomy,” whereas the removal of only one ovary is called “unilateral oophorectomy.” When both ovaries are removed, a woman will experience an instant and irreversible menopause, and will be unable to have children. Women under 50 who haven’t already had a natural menopause, that have an oophorectomy, will need to take some form of hormone replacement therapy (HRT), as the oestrogen produced by the ovaries is responsible for stopping the bones from thinning.

Osteoporosis A disease where the bones lose density, become thin and brittle and break easily. Having osteoporosis makes a person more likely to break their bones frequently and they take longer to heal. It can also lead to changes in posture – notably the formation of a hunched back. 

Ovaries The organs that produce eggs in the female body.

Ovarian cyst A growth in or on the ovary, filled with fluid. Called an endometrioma, when caused by endometriosis and filled with dark, old blood.

Ovarian Hyperstimulation Syndrome A side effect of fertility treatments that stimulate the ovaries to produce follicles (eggs). It can be life threatening. It occurs when too many follicles (with eggs) are produced.

Ovarian failure  When the ovary no longer responds to the hormone FSH and does not produce follicles (with eggs) – either because it is damaged or hasn’t formed properly or has no eggs left. This can be spotted by a blood test in which the FSH in the blood is raised. 

Ovulate/ovulation  When the egg is ripe and is released from the ovary. The follicle surrounding it breaks open and it will travel into the fallopian tube, to wait for fertilisation. If the egg then becomes fertilised it will travel into the womb and implant.


Pain The body’s response to damage or injury. It is subjective and everybody has different tolerances of pain. It is a message that travels through the nerves into the brain and is there as a defence mechanism - to alert us to when something has happened to us. It can range from mild discomfort to agony. Pain can be classified as acute or chronic; pain is usually defined as ‘chronic’ when it lasts 6 months or longer. Definitions of pain include, neuropathic, chronic, and visceral (coming from the organs).
Pelvic Inflammatory Disease (PID)  A ‘catch-all’ description for an infection in the pelvic area (around the fallopian tubes, ovaries etc). It can be caused by various bacteria – including developing from the sexually transmitted disease, Chlamydia. It can lead to damage of the pelvic organs, cause ectopic pregnancies, other complications and eventually cause infertility if serious or left untreated.
Peritoneum The thin tissue that covers the walls of the pelvis and abdomen on the inside, as well as the pelvic organs.

Physiotherapist A specialist healthcare professional who treats patients with exercises, activities and physical manipulation. Physiotherapists treat muscles and joint problems. They can be seen privately or under the NHS (with a referral from your GP).

Pituitary gland The area of the brain that acts as the ‘control centre’. It controls all hormonal functions, including reproductive organs.

Polycystic Ovarian Syndrome (PCOS) A condition found in women which results in the excess production of male sex hormones (androgens). It results in the presence of small cysts in the ovaries. Though PCOS can appear without any symptoms, some of the symptoms are irregular periods, excessive weight gain, acne, and excessive hair growth. It has been linked to problems with insulin and is sometimes treated with insulin medication.

Polyp  A polyp is a small growth of tissue (a tumour) inside the body. They can be benign or malignant.

Pouch of Douglas  The area between to womb (uterus) and the rectum (bottom). Another name for this is “Rectouterine pouch”. Endometriosis can grow here and be hard to find during a laparoscopy.  Having endometriosis here can cause the symptoms of painful sex. 

Pregnancy When a baby develops inside the womb, from being an embryo to developing into a foetus. Pregnancy lasts for nine months until the woman gives birth.

Premature menopause  Menopause that occurs naturally before the age of 40. Also known as premature ovarian failure.

Premature ovarian failure  A condition where the ovary runs out of eggs before the woman would normally go through a menopause.

Presacral neurectomy  A procedure where the nerves behind the womb are cut – the aim fo this to stop or reduce pain.

Progesterone  A female hormone which prepares the womb lining (endometrium) to receive and hold the fertilized egg to allow pregnancy.

Progestogens/Progestins  These are synthetic (artificially created) hormones that produce similar effects to progesterone. They are used most commonly in contraceptives but also as a treatment for endometriosis as they have an ‘anti-oestrogenic’ effect on the body which can shrink endometrial tissue; they can have severe side effects.

Prostaglandin  A substance that has a large number of functions in the body. It allows for the contraction and relaxation of muscle, the control of cell growth, the dilation (increasing) and constriction of blood vessels, control of blood pressure, and creation of inflammation. Prostaglandins cause the womb to contract and cause cramping. They can affect the spinal nerve and cause pain. In endometriosis, the endometriosis deposits are said to secrete (expel) prostaglandins which cause pain & inflammation.

Puberty  The time of life when the body begins making adult levels of sex hormones (oestrogen or testosterone) and starts developing adult body characteristics: developing breasts, growing facial and pubic hair, starting periods etc.




Rectum The last 6 to 8 inches of the large intestine (bowel). The rectum stores solid waste until it leaves the body through the anus (bottom). 

Reproductive age The time in which a woman can conceive a child – e.g. from the start of periods to the menopause.   

Resection  Surgical excision (removal by cutting) of a portion of an organ or other structure.

Retrograde menstruation When you have a period, some of the endometrium (womb lining) flows backwards, out  through the fallopian tubes and into the abdomen. This tissue may then implant itself on organs in the pelvis and grows. It has been suggested that most women experience some form of retrograde menstruation, but their bodies are able to clear this tissue and it does not deposit on the organs. This theory does not explain why endometriosis has developed in some women after hysterectomy, or why, in rare cases, endometriosis has been discovered in some men, when they have been exposed to oestrogen through drug treatments.


Salpingectomy The removal of the fallopian tube during surgery.

Side effects Problems that occur when medication or a treatment goes beyond the desired effect or problems that occur as well as the desired effct of the treatment/medication. All medications will have their side effects printed on the information leaflet. If you are ever unsure about this, please speak to your doctor or pharmacists or ring NHS direct (0845 46 47).

Sigmoidoscopy A procedure where a telescope is inserted through the back passage (bottom) and into the sigmoid colon (lower part of the intestine/bowel) to investigate for illness.

Surgery The treating of medical problems or illness through manual treatment – e.g. physically touching or cutting into the body. Usually is done under general anaesthetic or local anaesthetic so the patient doesn’t feel pain during it. Surgery normally carries risks.

Symptom Evidence of disease or illness that is only apparent to the patient. A doctor can see a sign of disease or illness  - for example a swollen ankle, but only the patient will know if it hurts (symptom). Pain is a symptom.


Testosterone  See Androgen

Tissue  A group of cells that perform specific functions in the body.  There are four types:

Epithelium - composed of layers that cover organ surfaces such as surface of the skin.
Connective tissue - holds everything together. 
Muscle tissue – parts of the inside of the muscle 
Nervous tissue - Cells which make up the brain, spinal cord and nervous system.  

Transvaginal surgery Surgical procedures carried out through the vagina. The surgeon would insert instruments through the vagina and into the abdominal cavity or womb. Some hysterectomies have been carried out this way. As this means not making an incision into the pelvis, it carries fewer risks.

Transvaginal scan An ultrasound performed through the vagina, using a special vaginal transducer. Transvaginal scans gives better resolution of the ovaries and fallopian tubes. The procedure is usually painless, noninvasive, and safe.

Tumour A mass of cells growing inside the body. They can be benign or cancerous.


Ultrasound An investigative procuedure where the inside of the body is looked at (visualised) using high-frequency sound waves. These waves bounce off tissues and organs inside the body. They are then converted into a picture called a sonogram. Ultrasounds allows doctors and their patients to get an inside view of the body in a safe, non-invasive way. Ultrasound is often used to examine a foetus during pregnancy. 

Uterine fibroids  Abnormal, benign (non-cancerous) growths of muscle within the wall of the womb.

Uterine polyps Abnormal, benign (non-cancerous) growths attached to a short stalk that protrudes from the inner surface of the womb. 

Uterosacral ligaments:  The supports that hold the womb in place inside the body. This is a common place to find endometriosis.

Uterus The womb. It is an organ inside the woman’s body which is responsible for carrying a foetus during pregnancy. The lining of the womb sheds every month, in response to hormones, if a fertilised egg is not received. The bottom or opening of the womb is called the cervix.


Vagina The muscular canal extending from the cervix to the outside of the body. The vagina allows for the transportation of body fluids (e.g. menstrual or ‘period’ blood or sperm) to and from the womb to the outside of the body. The vagina is also used during sexual intercourse, as the penis is inserted into it.

Vaporisation A method of destroying endometriosis by boiling the deposits with a laser. The heat causes the deposits to turn into vapour and disappear.


Womb The uterus. It is an organ inside the woman’s body which is responsible for carrying a foetus during pregnancy. The lining of the womb sheds every month, in response to hormones, if a fertilised egg is not received. The bottom or opening of the womb is called the cervix.







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