© Center for Endometriosis Care/Ken Sinervo MD, MSc, FRCSC. All rights reserved. No reproduction permitted without written permission. Revised since original publication and current as of 2023. No external funding was utilized in the creation of this material. The Center for Endometriosis Care neither endorses nor has affiliation with any resources cited herein. The following material is for informational purposes only and does not constitute medical advice.

THE “ENDOBELLY” BLOAT - A SYMPTOM OF ENDOMETRIOSIS?

Bloating happens, of course, for many reasons in tens of thousands of people (Almario, Ballal, Chey et al., 2018). Painful abdominal bloating, however, is significantly more common - and more severe - in those with endometriosis as compared to those who do not have the disease. Our patients tell us every day how bloating negatively impacts their lives. Bloating is, in fact, “widely recognized as a major symptom” in many who struggle with the disease and the subsequent consequences of endometriosis (Markham, Luscombe, Manconi et al., 2019). Bloating is not limited simply to menstruation, of course, and can occur in any individual with endometriosis at any time. In one retrospective observational study, abdominal bloating was among particularly strong markers for rectovaginal endometriosis, with a predictive prevalence of 89% - compared to 10% when the symptom was absent (Griffiths, Koutsouridou and Penketh, 2007).

It is true that bloating was once viewed as an “atypical” symptom of endometriosis (Louden, Wingfield, Read et. al., 1995). However, that dated assumption can likely be attributed to under-recognition of this common occurrence. Considering what we have long known about its prevalence as a ‘major symptom’ among endometriosis patients, then, it is quite surprising that any physician would not be highly familiar with bloating in the context of the disease by now. In fact, nearly two decades ago, Luscombe et al. (2009) admonished practitioners to pay attention to this very symptom. In their article, the authors wrote, “A significantly larger proportion of women with endometriosis than control subjects experienced abdominal bloating (96% vs. 64%)…the following were more common in those who had endometriosis: associated severe discomfort (30% vs. 0%), wearing loose clothes during bloating (87% vs. 38%)….[P]ainful abdominal bloating appears to be common...and causes considerable symptomatic distress.” Bloating can also persist following treatments for the disease.

In another study conducted to develop and evaluate a questionnaire intended to measure the long-term impact of endometriosis on different aspects of patient's lives, 91.25% indicated "bloating" as a symptom (Moradi, Parker, Sneddon et al., 2019). Maroun et al. (2009) also found that 90% of endometriosis sufferers had gastrointestinal symptoms, of which bloating was the most common at 82.8%. An even earlier study (Cameron, Rogers, Collins et al., 1995) reviewing the presenting features of intestinal endometriosis, specifically, found that abdominal bloating was prominent. Importantly, the authors also stressed the propensity of intestinal endometriosis to mimic other gastrointestinal disorders. Likewise, Moore et al. (2017) noted that many patients with endometriosis, who report ‘abdominal bloating, diarrhea and/or constipation’, are frequently misdiagnosed with IBS before an endometriosis diagnosis is confirmed. Of course, some individuals with endometriosis may actually have concurrent IBS (or other conditions).

In a more recent study on the effects of endometriosis on the perceptual aspects of body image, authors found that the majority of participants "reported pelvic pain and bloating, fatigue, and nausea symptoms" (Sayer-Jones & Sherman, 2023). Similarly, to encourage appropriate and swift treatment, Yu et al. (2023) encouraged gastroenterologists to "consider an endometriosis diagnosis" where patients present with pain, bloating, altered stools, and non-gastrointestinal symptoms. In still another report, bloating (among other symptoms) was found to be a significant correlate of health-related quality of life (Van Niekerk et al., 2022).

While we know that endometriosis can present with a broad range of indications, bloating remains a popular mention among them. For example, Alkatout et al. (2016) described “chronic pelvic pain, subfertility, dysmenorrhea, deep dyspareunia, cyclical bowel or bladder symptoms (e.g., dyschezia, bloating, constipation, rectal bleeding, diarrhea and hematuria), abnormal menstrual bleeding, chronic fatigue or low back pain” in their article on deep disease. One model built to predict the risk of endometriosis in infertile individuals also demonstrated “bloating” as an indicator of the disease (Ashrafi, Sadatmahalleh, Akhoond et al., 2016). In a more recent review, Patel et al. (2018) encouraged physicians to elicit a careful history from their patients (such as that which we do here in our Center), as it may lead to a suspicion of endometriosis. The authors noted, "patients may complain of a wide array of gastrointestinal symptoms such as abdominal bloating..."

Still, some practitioners may undervalue the importance of a detailed patient narrative, however, and the subsequent dismissal of many symptoms of endometriosis – not just bloating - is far from new. More than two decades ago, the Co-Founder of the Endometriosis Association penned a scathing indictment of the dismissal of symptoms like bloating, writing, "What do the following symptoms describe: pain during menstruation, irregular menses, excessive menstrual bleeding, pain during sexual intercourse, pain in the abdomen (other than when menstruating), nausea, abdominal bloating, diarrhea, back pain and urinary retention? Among other conditions, these symptoms may well describe endometriosis, right? Wrong. Although gynecologists experienced with endometriosis would easily make the diagnosis of probable endometriosis based on this list, according to the American Psychiatric Association (APA) these symptoms, taken together or in combination with other physical symptoms not listed here, describe a mental disorder called "somatization disorder…the kind of thinking behind somatization disorder is simply a new twist on that old bias about women." (Ballweg, 1995).

Bloating can occur regardless of the area(s) impacted by endometriosis. Ek et al. (2015) previously demonstrated that compared to controls, endometriosis patients experienced “significantly aggravated abdominal pain, constipation, bloating and flatulence, defecation urgency, and sensation of incomplete evacuation…” while noting that lesion-specific location was not associated with the symptoms (except increased nausea and vomiting among those who had endometriosis in or close to the bowel). Moore et al. (2017) further described how GI symptoms can frequently occur even in those individuals with endometriosis who do not have actual bowel involvement; an observation underlining earlier assertions that the disease has an indirect affect on enteric nervous system function.

Though bloating may persist even following intervention or suppression, removal (excision) of lesions may bring relief for some, and critically, can also confirm an accurate diagnosis. Although bloating can occur in those who do not have direct involvement, endometriosis can also - of course - directly involve the GI tract. For example, Parr et al. (1988) reported three decades ago on a small series of cases demonstrating the variety of presentations they were seeing. Two specifically complained of 'bloating' as a major symptom. As many others before and after them, the authors reported that "endometriosis of the bowel can present with a wide variety of symptoms which are commonly associated with other diseases...tissue diagnosis is of paramount importance..." In one case, a 30 year old presenting with symptoms including bloating was found at laparotomy to have a large endometrioma that had ruptured. Adhesions to the rectum and ileum were noted; the disease was resected (excised) and adhesions taken down (lysed). In the second, a 46 year old who had undergone a hysterectomy developed vaginal endometriosis and began experiencing symptoms including (but not limited to) ‘lower abdominal pain and bloating.’ Upon laparotomy, surgeons found endometriosis as confirmed by histology, which they again resected. Symptoms were subsequently relieved in these cases.

Presenting symptoms in still another case series included metrorrhagia (irregular uterine bleeding between periods), diarrhea, menorrhagia (heavy/prolonged bleeding with periods), rectal pain, shoulder pain, tenesmus (cramping rectal pain) and, of course, bloating. Incidentally, "acute appendicitis" was the first symptom of three of the patients. Authors cautioned that symptoms of GI endometriosis "are variable and can be acute or chronic" and concluded that "surgical removal is considered the best option for efficient treatment of pain and subfertility." They recommended the surgery be performed in the multidisciplinary setting (Houtmeyers, Ceelen, Gillardin et al., 2006). A larger, older series of 51 patients undergoing surgery for deep pelvic endometriosis with bowel involvement found preoperative complaints in patients ranging from dyspareunia to bloating (29.4%). Following laparoscopic excision of their disease, 87% reported a clinically significant improvement in symptoms overall (Duepree, Senagore, Delaney et al., 2002).

Some medications used for endometriosis can contribute to painful bloating as well. For example, researchers found that treatment with opioids or GnRH analogs can be associated with aggravated gastrointestinal symptoms - including bloating. GnRH drugs are often used for the temporary treatment of some symptoms associated with the disease, yet some patients may actually develop gastrointestinal dysmotility following their use. Ek et al. (2015) discovered that patients with current or previous use of GnRH analogs had “more severe abdominal pain” and “aggravated gastrointestinal symptoms” than the other patients in the study. Conversely, another study by Ferrero et al. (2010a) found that dual therapy consisting of letrozole and norethisterone acetate reduced pain and gastrointestinal symptoms in some individuals with colorectal endometriosis, including abdominal bloating. Their research (2010b) did not, however, find that administration of norethisterone acetate alone had any significant effect on constipation, abdominal bloating or the feeling of incomplete evacuation after bowel movements. Luscombe et al. (2009) also found that, compared with the unmedicated endometriosis group, those receiving hormonal treatment had “higher bloating severity ratings and discomfort scores.”

Diet may also play a role in exacerbation of symptoms. The Moore et al. study (2017), for instance, found that in cases of those with concurrent gut symptoms and endometriosis, the low FODMAP (fermentable oligosaccharides, disaccharides, monosaccharides and polyols) diet was generally helpful for symptomatic relief. Some patients have also expressed a reduction in bloating through use of anti-inflammatory or gluten free diets; eating smaller, more frequent meals; lowering their sodium intake; being sure to hydrate; and/or use of probiotics among other adjuncts. Others have also reported that being active/exercising helped reduce their painful bloating. PT may also assist in reduction of this painful symptom (and others).

In all, there is no question that bloating is experienced by many individuals with endometriosis, for varied reasons – some still unknown. In addition to the cursory review above, there are extensive accounts in the literature - dating back decades – of bloating as a symptom of the disease. One could also easily take a look at social media to see patients sharing actual photos of the occurrence. For example – as of this writing, there are 18,000+ posts on just Instagram alone for #endobelly.

We don’t need social media or the literature to know that bloating negatively impacts our patients with endometriosis, however.

We just listen to them.

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