The internet is full of information about endometriosis. Some of that information is really helpful, and some of it can be misleading. Here are some useful websites for information about endometriosis:

• Organisations (not run by doctors) that provide information about endometriosis:

  • Endometriosis New Zealand

  • Endo Warriors Aotearoa

  • QENDO (Australian, lots of really good detailed information)

• Official endometriosis guidelines (these are aimed more at doctors than patients, but summarise what international studies show and determine what is accepted as "best practice")

  • RANZCOG (Royal Australian and New Zealand College of Obstetricians and Gynaecologists) Living Evidence Guideline: Endometriosis (Fist published in 2025, Updated every 3 months)

  • ESHRE (European Society of Human Reproduction and Endocrinology) Endometriosis Guideline 2022

• Apps (for tracking symptoms, medications, linking with other people with endometriosis and more)

  • QENDO (based in Australia, free)

  • Endo45 (based in NZ, weekly/monthly/yearly fee)

  • Matilda (based in Australia, one off fee for programme around endometriosis surgery)

Endometriosis is a condition that we don't understand very well (despite lots of research). It is very common (estimated 1 in 9 women).

It is defined as growth of tissue that is similar to the endometrium (lining of the uterus - the bit that bleeds with a period) growing somewhere it shouldn't. This can be anywhere in the pelvis (on the ovaries, the wall of the pelvis, the outer surface of the uterus), on the bowel or the bladder, and sometimes outside of the pelvis, like on the appendix, the diaphragm (the muscle that controls breathing between the chest and abdomen), just below the skin in a caesarean section scar, and other places. 

We don't know how it gets there, or why it sometimes comes back after treatment. There are lots of theories.

There are three main types of endometriosis: superficial endometriosis (on the surface of structures, hard to see on ultrasound but usually easy to see with surgery); deep endometriosis (invading beyond the surface into the underlying structures, usually easy to see on ultrasound and with surgery) and endometriomas (cysts on the ovary caused by endometriosis). These three types may be three completely different conditions, or may be all part of the same condition; we have lots of theories, but nobody really knows for sure.

Because endometriosis is similar to the endometrium, it responds to hormones. Hormones that trigger a period also trigger bleeding and inflammation in endometriosis. This means that when someone with endometriosis is having a period, they are also having bleeding and inflammation at other parts of their body. This can trigger symptoms directly where the endometriosis is, as well as in nearby structures. For someone with endometriosis, a period might cause higher levels of pain, but might also trigger symptoms related to the bowel or the bladder. A common symptom is pain with bowel motions that is much worse with periods.

It is common for endometriosis to occur within the abdomen near the top of the vagina. This can mean that penetrative sex can trigger symptoms. This is often described as a pain deep within the belly (rather than in the vagina, which may be more likely to be caused the pelvic floor muscles). The pain is often worse in certain positions, and can be during and/or after sex, often lasting for hours or even days.

Traditionally endometriosis always needed surgery to be diagnosed. Recently, there have been big improvements in ultrasound, and now in many cases ultrasound can diagnose endometriosis. However, for an ultrasound to reliably diagnose endometriosis the person doing the scan needs to have specific training in scanning for endometriosis. A general pelvic ultrasound may miss many of the subtle signs of endometriosis. The availability of true endometriosis scans in Aotearoa is limited unfortunately, although improving all the time.

A pelvic ultrasound may confirm endometriosis, or may be suggestive of endometriosis, or may not show any signs. A scan that does not show endometriosis does not completely rule it out, but generally is pretty good at ruling out deep endometriosis and endometriomas (ovarian cysts related to endometriosis). 

Laparoscopic (keyhole) surgery can identify and treat all types of endometriosis, but always carries some risk. The more widespread and deep the endometriosis, the higher the risks of surgery. Because of these risks, surgery is not always recommended; the decision for surgery needs to be individualised to each person and can vary depending on their goals and values, their symptoms, their risk profile for surgery, their fertility situation and a range of other factors.

Surgery is one option for managing endometriosis. Endometriosis can return after surgery, and we have no science to tell us whether this is because not all of the endometriosis was treated (including microscopic deposits), or whether completely new endometriosis develops. This means that surgery is unfortunately not always a lifetime cure. That means that medical (hormonal) treatment to suppress endometriosis can be better than surgery for some people giving longer lasting results. In some cases, however, symptoms don't respond well to medical treatments and surgery can give better results. In other cases, medical treatment is not an option (such as people trying to fall pregnant, or those who may have medical reasons not to take hormonal medications or side effects that aren't acceptable).

When deciding whether surgery is the right option, all of the below points need to be considered:

• All surgery carries risk. The risk of endometriosis surgery can be very minor for a fit and healthy person with no previous surgery and suspected mild to moderate endometriosis. This risk can increase significantly with medical conditions, previous surgery or obesity; or with moderate to severe endometriosis, especially if the bowel is involved.

• The first laparoscopy probably gives the best results. Endometriosis can recur, generally it is expected that within the first 5 years or so after surgery symtpoms should be improved. Repeat surgery is less likely to give a good improvement in symptoms, and carries more risk due to scar tissue that forms after surgery. For this reason there is value in not operating immediately, especially in younger people.

• Not all endometriosis surgery improves symptoms. Many people have endometriosis resected and don't notice a big improvement in symptoms. It's important to understand all the possible factors contributing to pain and other symptoms, and have realistic expectations about how surgery might improve those symptoms specifically.

• Sometimes no endometriosis is found. In these cases, the surgery won't improve symptoms, and the main benefit is ruling out endometriosis as a cause for the symptoms. There are many other avenues to pursue for treating symptoms in this case, but it's important to know that this can happen, and can be a difficult situation.

When all of these things are considered, if both you and your gynaecologist feel that surgery is warranted and likely to help with your symptoms, then it's important that you have a good understanding of the risks and what to expect before, during and after surgery.