In endometriosis, tissue similar to the lining of the uterus (known as the endometrium) grows on organs and tissues outside the uterus. It typically affects the ovaries, fallopian tubes and the tissue lining the pelvis. However, it can grow anywhere in the pelvis.
Just like the lining of your uterus, this abnormal tissue builds up, breaks down and bleeds each month in response to changing hormone levels. However, unlike your period, there is no way for this blood and debris to leave the body. This leads to inflammation (irritation and swelling of the affected areas) and the formation of scar tissue known as ‘adhesions’. Over time, these fibrous bands of scar tissue may cause tissues and organs to stick together. In more advanced disease, this knitting together of structures can interfere with an organ’s normal function.
About 20 to 25% of women with endometriosis do not experience any symptoms at all.2 In fact, some women only find out they have it when they experience trouble falling pregnant.
For other women, pain is the predominant symptom. Pain is typically worse during a woman’s period, but can occur at any time throughout the month. Endometriosis is also usually associated with heavy periods, longer periods (greater than five days), and spotting or bleeding between periods.
Depending on the structures involved, endometriosis may also cause bladder or bowel irritation. This can lead to pain, urinary frequency and difficulty with bowel movements. Some women may also experience pain during intercourse.
Between 30 to 50% of women with endometriosis will experience trouble conceiving.2 There are a few different ways endometriosis may cause fertility issues.
In advanced or late stage disease, endometriosis can interfere with the function of reproductive structures like the fallopian tubes and ovaries. For example, one or both fallopian tubes may become inflamed and the ovaries may develop cysts, known as endometriomas. The tubes may become blocked, making it difficult for eggs to enter or travel along the tubes towards the uterus. These blockages can also hinder sperm from entering the fallopian tubes, making it harder for sperm to meet and fertilise an egg.3
When endometriosis affects the ovaries, cysts and scar tissue can also prevent ovulation (the release of an egg from the ovary each month), particularly if the ovary has become stuck to the wall of the pelvis. In this case, there is no egg available for fertilisation, even if sperm is able to gain access to the fallopian tubes. Inflammation and its related toxins may also reduce egg quality and ovarian reserve (the number of good quality eggs remaining in the ovaries), reducing the chances of a successful pregnancy.
Additionally, pain associated with endometriosis may make it difficult to conceive naturally, as chronic pain and pain during intercourse may make sex very difficult.
We don’t fully understand how endometriosis leads to fertility issues in women with milder disease. In this case, the reproductive organs are not severely affected. However, the inflammation associated with endometriosis may be toxic to the egg, sperm and/or embryo. It may also reduce the ability of an embryo to implant in the lining of the uterus,4 an important step in conception.
It is important to note that endometriosis does not always affect fertility. If you have endometriosis and are experiencing difficulty conceiving, it’s important to undergo a thorough assessment by a fertility specialist to help determine if it is your endometriosis and/or other issues that are affecting your ability to conceive. An assessment of the male partner (where relevant) is also important for identifying any male-factor infertility that may be contributing to a delay in falling pregnant.
There are a range of treatments that can help women with endometriosis conceive. These include assisted reproductive techniques (ART), as well as options that increase your chances of falling pregnant naturally. The most appropriate treatment for you will depend on your medical history, the severity of your endometriosis, and whether your fertility specialist believes that this is the primary cause of your fertility issues.
Intrauterine insemination (IUI) is a procedure where a very large number of sperm are introduced into your uterus to increase the chances of egg and sperm meeting. In this procedure, a sperm sample from a partner or donor is concentrated in the lab to contain a very high number of sperm. The concentrated sample is then injected into your uterus soon after you have ovulated.
Your fertility specialist may also prescribe medication to help your body release more than one mature egg from the ovary before you undergo IUI, as there is evidence that this increases the chances of success in endometriosis.4 IUI is most likely to be suitable for women with mild to moderate endometriosis who have no blockages in their fallopian tubes.
Laparoscopic (keyhole) surgery is a minimally invasive procedure that can identify and treat endometriosis. In this procedure, a small incision is made near the belly button, and a thin and flexible telescope is used to look inside the abdomen. Any growths that are found are then treated. Removing endometriosis that is blocking or ‘distorting’ reproductive organs may improve their function and improve fertility.3
In the months following surgery, natural fertility may increase. Laparoscopic surgery can also give you a better chance of successful pregnancy after ART, such as in vitro fertilisation.
IVF is most likely to be recommended as a first-line treatment when there are other factors also impacting your fertility. This may include older age (fertility naturally declines with age), advanced endometriosis, or low sperm quality in the male partner.
In IVF, several of your eggs are extracted from your ovaries and mixed with sperm in laboratory dishes. If the sperm are of good quality and swim well, they are left to enter the eggs on their own, much like they would in natural conception (this is called ‘standard insemination’). In cases where the sperm sample is lower quality or doesn’t move well, the best sperm can be selected and injected directly into each egg, making it much easier for them to unite and form an embryo. This process is called intracytoplasmic sperm injection (ICSI). The highest-quality embryo will then be placed in your uterus, where it will hopefully embed and develop into a successful pregnancy. Any remaining embryos can be frozen and stored for later use, if needed.
Depending on your medical history and circumstances, your doctor may prescribe medication to reduce your oestrogen levels for three to six months before IVF. Oestrogen is the main female sex hormone and promotes the growth of the endometrium in the first half of your menstrual cycle. Remember that endometriosis responds to hormones in the same way your uterus does; reducing oestrogen levels can therefore help to reduce the volume of abnormal growth prior to IVF. As a result, these medications may improve IVF success rates in women with endometriosis.3
Tubal flushing is commonly used as a diagnostic technique to check for blockages in the fallopian tubes. However, tubal flushing with oil can also increase your chances of conceiving naturally in the months following the procedure. In tubal flushing, an oil-based liquid is introduced into the uterus through a tube placed in your cervix. The solution then makes it way through your fallopian tubes, ‘flushing’ them out and potentially removing blockages.
In many women, endometriosis progresses with time. In addition, natural fertility declines with age. This means it may be harder to have a baby when you are older. If you are young and not ready to have a baby, we may advise you to consider freezing your eggs. This will ensure you have some high-quality eggs available should you find you need the assistance of IVF in the future.