Endometriosis is a condition in which the tissue that lines the uterus, the endometrium, develops in abnormal sites, typically on the bowel, the outside of the uterus, the ovaries and the peritoneum. Rarely it can also develop in the lungs and pleura surrounding the lungs.

Like the endometrium, endometriosis tissue undergoes cyclical changes in response to the natural hormonal cycles, leading to loss of the glandular tissue and bleeding like menstruation from the sites of endometriosis implants. This causes fibrosis and scarring leading to cyclical pain at the sites of the implants, heavy and painful periods and pain with sex (dyspareunia).


The curious thing about endometriosis is that the symptoms it causes are not related to the size or extent of the lesions. Therefore some women can experience disabling pain with only a small isolated spot of endometriosis which may not cause any symptoms in another woman, whilst others can have very extensive endometriosis with adhesions and scarring affecting the bowel, ovaries and peritoneum and yet have very little in the way of symptoms.

Endometriosis can cause delay in conception and the condition is found in up to 30% of women presenting with infertility.


It can be difficult to diagnose endometriosis because the symptoms can vary considerably and there are many other conditions that can cause similar symptoms. Your gynaecologist may therefore recommend a number of different tests. Endometriosis can only be confirmed with a surgical examination called a laparoscopy.


Medical treatment incudes the use of progesterone, either orally or from the Mirena intrauterine system, oral contraceptives, gonadotrophin releasing hormone analogues (GnRH-a) such as Zoladex which is given by monthly injection and causes temporary reduction of oestrogen levels and menopausal symptoms which also causes temporary shrinkage of the endometriosis lesions.

Surgery to ablate or excise the areas of endometriosis is very successful and has been shown to improve the chance of spontaneous conception. Up to 80% of women will remain asymptomatic for up to 5 years following such surgery and many will conceive during this window, not least because sex can be less painful.

Laparoscopy with laser ablation is our treatment of choice for this condition, endometriotic cysts can also be treated in this way, but sometimes the disease is so extensive that a more difficult and demanding operation is required, with removal of affected segments of bowel in the worst cases.

More information & further reading

ESHRE guideline for the diagnosis and treatment of endometriosis
Stephen Kennedy, Agneta Bergqvist, Charles Chapron, Thomas D’Hooghe, Gerard Dunselman, Robert Greb, Lone Hummelshoj, Andrew Prentice, Ertan Saridogan.

Peritoneal fluid, endometriosis, and ciliary beat frequency in the human fallopian tube
The Lancet, Volume 360, Issue 9341, Pages 1221-1222
Rachel A Lyons, Ovrang Djahanbakhch, Ertan Saridogan, Alan A Naftalin, Tariq Mahmood, Anthony Weekes, Rashna Chenoy

Laparoscopic ovarian suspension to facilitate surgery for advanced endometriosis
Fertility and Sterility, Volume 82, Issue 3, Pages 702-704. 2004
Alfred S. Cutner, Michael S. Lazanakis, Ertan Saridogan

Short-term outcome of fertility-sparing laparoscopic excision of deeply infiltrating pelvic endometriosis performed in a tertiary referral center
George K. Pandis, Ertan Saridogan, Alastair C.J. Windsor, Cagri Gulumser, C. Richard G. Cohen, Alfred S. Cutner. 2010