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What Is Endometriosis? Symptoms to Recognize It

Endometriosis is a common condition that affects about 190 million people worldwide. As of today, the condition is very difficult to diagnose and treat. Why is this? Dr. Krina Zondervan — co-director of the Endometriosis CaRe Centre in Oxford — sheds light on this important question. 

Interview has been edited for clarity.

What’s the importance of endometriosis awareness?

Endometriosis is a common condition that affects about 190 million people worldwide.

This is a condition where cells and tissue that normally line the uterus, called the endometrium, end up somewhere else in the pelvis. 

With every period, these bits of tissue respond to hormones, and they bleed like your normal endometrium would do, and that creates problems. These small bits of disease essentially create wounds. 

One of the key symptoms of endometriosis is pelvic pain, especially during periods, but also pain during sex or pain at other times during the menstrual cycle. 

Dr. Zondervan says that endometriosis awareness is so important because it’s a very under-recognized condition. 

She suspects that one of the reasons it could be that endometriosis doesn’t get much recognition is because there’s a stigma around talking about period pain. “Although we’re working on making it a topic that is more acceptable to talk about, I think for a lot of people it’s still difficult.”

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She says another element is that a lot of doctors find it very difficult to diagnose endometriosis. Symptoms like pain during periods can also be caused by other conditions. 

“So, endometriosis remains very difficult to both diagnose and treat. That’s why, given that it’s such a common problem, we really need to devote more attention to it.”

What causes endometriosis?

According to Dr. Zondervan, one of the main theories of endometriosis origin is that some of the endometrium that’s shed during periods goes into the uterine tubes and ends up in the abdominal cavity, rather than coming out along with the rest of the period flow. This is a phenomenon called retrograde menstruation. 

“It’s pretty well-established that this is a process that will happen to most people who get periods to a certain extent, but in people with endometriosis, some of the cells that are in that menstrual blood manage to stick to surfaces within the pelvis. And we don’t really know why that is so. We do think that most endometriosis probably originates from this process during periods.” 

Dr. Zondervan says there are also some other theories about how endometriosis occurs. One of them is that cells within the pelvis can change to a cell type that is similar to the endometrium. “We call that metaplasia. But that’s likely to be a rare occurrence. There are examples of cases where we think that this might be happening, e.g., there are very rare cases of endometriosis in males who have had hormone treatment and clearly — since they don’t have periods — this isn’t caused by retrograde menstruation. But those instances are extremely rare.” 

She also adds: “We think that retrograde menstruation is the main origin of endometriosis. But there are lots of factors in people who do develop endometriosis that predispose them to those endometrial cells being able to stick and cause problems.”

What are the symptoms of endometriosis?

Dr. Zondervan says that it can be difficult to tell the difference between period pain and pain that warrants medical treatment: “I think one of the first things to ask yourself is if the pain is so bad that it really affects your daily life. That’s something that should be checked out, whether it’s endometriosis or something else. 

It could be that endometriosis doesn’t get much recognition because there’s a stigma around talking about period pain. Although we’re working on making it a topic that is more acceptable to talk about, I think for a lot of people it’s still difficult.

“Particularly period pain, but also pain during sex, or pain at other times that is so bad that you have to take pain medication to really get through the day, or it affects you some other way. That’s not normal, and that’s why you should have that checked out.” 

Dr. Zondervan says that it may not be endometriosis, but it needs to be investigated, and it is something to be aware of. “These are not symptoms that should simply be ignored or put up with, which is what a lot of people over the decades and centuries have done.” 

For endometriosis, these are the main symptoms to watch for:

  1. Pain is the main one. 
  2. Tiredness that often comes with pain. 
  3. Difficulty getting pregnant. 

Dr. Zondervan notes that not everyone has difficulty getting pregnant. There are a lot of people out there who have been diagnosed with endometriosis who’ve been told, “you should try getting pregnant soon because you might have a problem,” and then they get pregnant very quickly, but other people do struggle for many years. 

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