Understanding the difference between endometriosis and fibroids by Dr James Hopkisson

Globally, March is recognised as Endometriosis Awareness Month. For the 10% of women and people assigned female at birth of reproductive age living with the condition, it holds significant importance, helping to shine a light on its debilitating symptoms and devastating impact on daily life. 

In the UK, it can take on average between 8-10 years to receive a diagnosis for endometriosis, making it all the more important to recognise its symptoms, its impact on female fertility and other conditions that present themselves in a similar way. 

What is endometriosis?

Endometriosis is a complex condition where cells similar to those found in the uterine lining grow outside of it. Most commonly, we observe these cells growing in the ovaries and pelvis, but in more extreme cases it can affect areas such as the bladder and bowel. 

To determine the severity of the condition in a given patient, there are four stages of endometriosis, each categorised by the location, size and depth of the tissues growing. Stage one is considered ‘minimal’ or ‘mild’ with small spots of endometriosis causing inflammation in or around the pelvic cavity. Stage four, on the other hand, is deemed ‘severe’ where tissue has become implanted in or on the ovaries and pelvic lining and in some cases the fallopian tubes. 

At present, the exact cause of endometriosis remains unknown, though there is some evidence to suggest hormonal and genetic influences, and there is no long-term cure for those living with the condition. Throughout their reproductive years, the majority of people with endometriosis will experience severe pelvic pain and excessive bleeding associated with their menstrual period, painful sexual intercourse and spotting between periods, all of which can be chronic, leading to fatigue and exhaustion. On top of this, the effects these symptoms can have on a person’s mental health, often causing anxiety and a disruption to working life, is often overlooked or dismissed. Many patients speak of needing to take time off of work during their menstrual period and that carrying out basic daily tasks can become almost impossible due to extreme pain. 

How is endometriosis diagnosed?

Despite the prevalence of the condition, for many, a diagnosis for endometriosis comes only once they have already started trying to conceive. It may be that their symptoms have been more manageable over the years, or because some methods of hormonal contraception can mask the symptoms altogether, particularly those that eliminate a monthly menstrual period. 

Arguably, the delay in receiving an endometriosis diagnosis may also be because a laparoscopy, a minimally invasive surgical procedure, is most frequently needed. During the procedure, surgeons will remove endometrial lesions by burning away the affected tissue, making it both a method of diagnosis and treatment. Other treatment options include analgesics, pain modifying drugs and hormonal therapies, including contraceptive methods such as the progesterone only pill and the hormone coil. 

What’s the difference between endometriosis and fibroids?

The crossover in symptoms between endometriosis and other conditions that affect female reproductive health, make it all the more crucial to understand the key distinctions between them to ensure the correct diagnosis and appropriate care is received. 

Fibroids, also known as uterine fibroids, is one such condition that is commonly compared to endometriosis. The two conditions are entirely different, though they can occur together. Fibroids are benign tumours that develop from the muscle cells within the wall of the uterus. They can appear as single growths or in clusters and vary in size - from as small as a seed to as large as a grapefruit. They are extremely common, thought to affect 70-80% of women during their reproductive years, although only a third of patients will experience any symptoms. Like endometriosis, these symptoms can include excessive bleeding, painful sexual intercourse, pelvic pressure and frequent urination. However, unlike endometriosis, these symptoms are often related to the size and number of fibroids present, rather than the menstrual cycle. 

Fibroids can be diagnosed using either an ultrasound or MRI and treatments include hormonal therapies, pain medications and lifestyle changes or in more extreme cases, a surgical procedure to remove them. Unfortunately, neither condition comes with a long-term treatment option as both endometrial tissue and fibroids can grow back. 

How do endometriosis and fibroids affect fertility?

Due to the complexity of the condition and its varying stages, endometriosis can affect a person’s fertility in different ways. This can include causing damage to the reproductive organs, scarring or blocking the fallopian tubes and inflammation that may impact egg reserve and implantation of the embryo. 

Infertility caused by fibroids is also common, particularly as they are more prevalent in women during the later years of their reproductive life. Larger fibroids especially can be problematic as they may block the fallopian tubes, distort the uterus and disrupt the implantation process. They have also been linked to recurrent miscarriages and may cause complications during pregnancy, such as abdominal pain and a higher risk of premature labour. 

While natural conception is not impossible with either condition, those with endometriosis may find it takes longer than usual to conceive. For many, however, fertility treatments such as egg freezing and IVF become the only method for protecting future fertility and achieving a pregnancy. But like with all aspects of fertility, timing is crucial and seeking medical advice as soon as you identify any concerns will give you the best chance of success later on.