Painful menstruation and general pelvic pain have always been considered the hallmarks of endometriosis. While pain is obviously common with endometriosis, research suggests that gastrointestinal (GI) symptoms may often be overlooked. Studies have shown that these GI symptoms - including bloating, nausea, constipation, and diarrhea - are even more common, with more than 90% of women experiencing at least one of these complaints. Bloating is such a familiar occurrence for women with endometriosis that it even has a nickname: endo belly.
A recent study out of Australia took a detailed history from more than 350 women with suspected endometriosis prior to surgery, determining what symptoms were most common and how those correlated with the presence of endo.
As we would expect, the most common pain symptom with endometriosis is painful periods (dysmenorrhea), which affected more than 8 in 10 women. General pelvic pain affected 2 in 3 women, and half reported pain in their legs or thighs.
One extremely important finding is the presence of low back pain in 3 out of 4 women with endometriosis. This is higher than the rate of painful intercourse, general pelvic pain, or leg/thigh pain. In fact, only painful periods are more common for women with endometriosis.
Much of this may be due to the connection between the pelvic floor and the low back. The pelvic floor is a stabilizer for the low back, so pelvic floor dysfunction can refer pain anywhere in the pelvic girdle. Other studies have shown that 95% of women with chronic low back pain have pelvic floor dysfunction as well, so there is clearly a close connection.
Infertility is often a reason to suspect endometriosis - of the women in this study who were infertile, nearly 90% were found to have endo. However, as a broad population, infertility is less common than both pelvic pain or GI symptoms with endometriosis, affectingly only 25% of women suspected of have endometriosis.
However, other studies have reported up to 50% of women with endometriosis struggle with some level of infertility or lowered fertility.
By far the most common GI symptom associated with endometriosis was abdominal bloating, which affected more than 80% of women. Nausea was reported by more than half of women, and both constipation and diarrhea found in 1 in 3. More than 20% of the population had previously been diagnosed with Irritable Bowel Syndrome (IBS).
Of interest is that these GI symptoms don't seem to be associated with endometriosis of the bowels. Fewer than 10% of women with GI symptoms had bowel lesions (7.6%), and bowel lesions were found at approximately the same rate regardless of whether a woman had GI symptoms or not. This suggests that the connection between endometriosis lesions and GI symptoms is complex and indirect.
Many women with GI symptoms like bloating, constipation, diarrhea, or nausea may be diagnosed with conditions like IBS when endometriosis may be the underlying cause or a contributing factor. In treating endometriosis, it's important to pay attention to GI symptoms in addition to pain and possible infertility. When a person has not been diagnosed with endometriosis, it is important to consider these GI symptoms as a potential sign of endo, especially when the person is also experiencing other hallmark signs such as pelvic pain, painful sex, or painful periods.
Dr. Nicole Cozean is the founder of PelvicSanity physical therapy, Orange County's premier pelvic floor physical therapy clinic. One of only 270 PTs to be board-certified in the pelvic floor, and the first PT to serve on the ICA Board of Directors, Nicole is the author of the acclaimed and best-selling book The Interstitial Cystitis Solution (2016). She is an adjunct professor at her alma mater, Chapman University. The PelvicSanity blog focuses on presenting practical, positive information to help patients beyond the walls of Nicole's clinic.