{"paper_id":"88378616-26c2-4bc8-920c-cb0acf83de6e","body_text":"RESEARCH Open Access\n© The Author(s) 2025. Open Access  This article is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 \nInternational License, which permits any non-commercial use, sharing, distribution and reproduction in any medium or format, as long as you \ngive appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if you modified the \nlicensed material. You do not have permission under this licence to share adapted material derived from this article or parts of it. The images or \nother third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the \nmaterial. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or \nexceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit  h t t p  : / /  c r e a  t i  \nv e c  o m m  o n s .  o r  g / l  i c e  n s e s  / b  y - n c - n d / 4 . 0 /.\nKeukens et al. BMC Women's Health          (2025) 25:174 \nhttps://doi.org/10.1186/s12905-025-03715-1\nBMC Women's Health\n*Correspondence:\nA. Keukens\nannekeukens@hotmail.com\nFull list of author information is available at the end of the article\nAbstract\nBackground Patients with endometriosis often experience bowel symptoms such as changing stool, abdominal pain \nand bloating similar to those associated with irritable bowel syndrome. These symptoms reduce quality of life (QoL). \nVisceral hypersensitivity seems to be a shared pathogenic factor. The low-FODMAP (Fermentable Oligosaccharides, \nDisaccharides, Monosaccharides and Polyols) diet is a known visceral hypersensitivity targeted therapy with significant \nreduction in bowel symptoms. The aim of this study was to evaluate the effect of low-FODMAP diet on bowel \nsymptoms such as constipation and bloating, pain and QoL in patients with endometriosis.\nMethods The diet involved four weeks of FODMAP elimination, followed by a reintroduction-period of at least \nten weeks, varying by patient. Questionnaires were sent at baseline and after these periods. The primary outcome \nwas constipation change after the reintroduction period compared to baseline, assessed by Groningen-DeFeC-\nquestionnaire (0–30 scale) with paired-T-test or Wilcoxon-signed-rank-test. Secondary outcomes included changes \nin bloating, QoL and abdominal pain, assessed by Endometriosis Health Profile-30 (EHP-30). P-value < 0,05 indicated \nstatistical significance.\nResults Forty-seven patients were included; thirteen withdrew before starting the diet, mostly due to lack of \nmotivation. Of the remaining 34, 24 (71%) completed the diet (i.e. following the prescribed periods) Constipation \nscores improved significantly after low-FODMAP diet compared to baseline from 7.0 to 5.0 (p = 0.023). There was \nno significant difference observed in bloating, however 53% of patients that completed the diet mentioned a \ndecrease. The following domains of the EHP-30 improved significantly: pain (from 47.8 to 29.2 (p = 0.002)), control and \npowerlessness (from 69.4 to 36.7 (p = 0.000)), emotional well-being (from 45.2 to 29.2 (p = 0.001)), social support (from \n46.4 to 31.3 (p = 0.0017)), self-image (from 51.2 to 40.5 (p = 0.035)), work-life (from 35.0 to 21.7 (p = 0.003)) and sexual \nintercourse (from 61.6 to 45.7 (p = 0.023)). 65% of patients that completed the diet mentioned a decrease in pain, \nespecially chronic pelvic pain.\nConclusions This study suggests the low-FODMAP diet may improve bowel symptoms and QoL in endometriosis \npatients motivated to follow the diet, highlighting its potential in endometriosis care. However, further research in \nlarger populations is needed to explore factors like endometriosis type, pain intensity and dropout rates to confirm \nthese findings.\nEffects of a low-FODMAP diet on patients \nwith endometriosis, a prospective cohort \nstudy\nA. Keukens1,2*, V. B. Veth1,2, M. M.A van de Kar4, M. Y. Bongers2, S. F.P .J. Coppus1 and J. W.M. Maas2,3\n\nPage 2 of 8\nKeukens et al. BMC Women's Health          (2025) 25:174 \nIntroduction\nEndometriosis is a benign, chronic disease that is defined \nas the presence of endometrium-like tissue outside the \nuterine cavity causing a chronic inflammatory reaction \n[1]. Whilst not all patients are symptomatic, frequently \npresented symptoms are dysmenorrhea, chronic pelvic \npain, dyspareunia, infertility and bowel symptoms. Up to \n90% suffer from bowel symptoms like changing stool and \nbloated feeling [ 2]. Compared to controls, patients with \nendometriosis suffer from more severe abdominal pain, \nconstipation, bloating and flatulence, impaired psycho -\nlogical well-being, influence of symptoms on daily life, \ndefecation urgency, and sensation of incomplete evacua -\ntion [2]. Almost 30% of patients undergoing laparoscopy \nfor suspected endometriosis experience constipation \n[3]. These bowel symptoms are similar to those typically \nassociated with irritable bowel syndrome (IBS). Both \ndiseases have a great impact on quality of life (QoL) [ 4, \n5]. Patients with endometriosis have an approximately \nthreefold increased risk of developing IBS [ 6]. Visceral \nhypersensitivity is a factor that seems to play a role in \nboth endometriosis and IBS [ 7]. This is an increased sen-\nsitivity to pain signals from internal organs, resulting in \nlower pain thresholds. Studies on rectal distension show \nthat individuals with IBS and individuals with endome -\ntriosis experience more pain compared to healthy indi -\nviduals [7, 8]. Visceral hypersensitivity also might explain \nwhy patients with IBS or endometriosis sometimes expe -\nrience chronic abdominal pain despite the severity of the \ndisease and the absence of clear structural abnormalities \n[7, 9]. \nThe low-FODMAP (Fermentable Oligosaccharides, \nDisaccharides, Monosaccharides and Polyols) diet is a \nknown visceral hypersensitivity targeted therapy for IBS, \nwith significant reduction in bowel symptoms [ 10, 11]. \nThe diet involves elimination of poorly absorbed carbo -\nhydrates, reducing intestinal water volume and colonic \ngas production. Gastro-intestinal symptoms such as \nabdominal pain and a bloated feeling should diminish or \neven vanish because of reduction of intestinal luminal \ndistension.\nSince effective long-term treatment options for endo -\nmetriosis remain limited, self-management strategies like \ndietary interventions are used to control symptoms of the \ndisease [12]. \nAlthough limited data are available on the impact of \ndietary interventions such as the low-FODMAP diet on \nbowel symptoms in patients with endometriosis, some \nstudies suggest promising results. A study using pro -\nspectively collected data found that the low-FODMAP \ndiet significantly reduced bowel symptoms in patients \nwith both IBS and endometriosis compared to those \nwith IBS alone [ 13]. Additionally, a recent prospective \nstudy reported that adherence to the low-FODMAP \ndiet or endometriosis diet (i.e. an experience-based diet \nthat emphasizes anti-inflammatory, fiber-rich foods and \nlimits processed foods, sugars, and dairy) resulted in \nimprovements in pain, quality of life, and gastrointestinal \nsymptoms compared to no diet [ 14]. More prospective \nstudies will add evidence to this field. And, to our knowl -\nedge, the effect of the low-FODMAP diet on functional \nscores, like constipation, in endometriosis has never been \nstudied before.\nThe previous results and common symptoms in IBS \nand endometriosis suggest that this diet could, non-\ninvasively, result in bowel symptoms reduction in our \npopulation of patients with endometriosis, and therefore \nimprove their QoL. The objective of this study is to evalu-\nate the effect of the low-FODMAP diet on bowel symp -\ntoms such as constipation and bloated feeling, QoL and \nabdominal pain in patients suffering from endometriosis.\nMethods\nStudy design\nThis single center prospective cohort study was car -\nried out as a pilot study at the Máxima Medical Cen -\nter, a teaching hospital in Veldhoven, the Netherlands. \nThe study was registered prospectively on September \n13th 2019 in the Dutch Trial Register (NL8022) and \nwas conducted according to the principles of the Dec -\nlaration of Helsinki and approved by the National Cen -\ntral Committee on Research involving Human Subjects \n(NL71354.015.19) and the medical ethical research \nTrial registration ICTRP: NL-OMON28996: Feasibility study: The effect of the low FODMAP diet on women suffering \nfrom endometriosis ( h t t p  s : /  / t r i  a l  s e a  r c h  . w h o  . i  n t /  T r i  a l 2 .  a s  p x ?  T r i  a l I D  = N  L - O M O N 2 8 9 9 6) on September 13th 2019.\nKey message\nThis study shows in patients with endometriosis following the low-FODMAP diet a significant decrease in \nconstipation scores and multiple domains of quality of life. It should be noted that these effects were observed in \na motivated group that completed the diet. The low-FODMAP diet is a promising non-medical, self-management \nintervention in endometriosis care.\nKeywords Endometriosis, Constipation, Bloating, Pain, Diet therapy, Low FODMAP diet, Self-management, Quality of \nlife\n\nPage 3 of 8\nKeukens et al. BMC Women's Health          (2025) 25:174 \ncommittee of the Máxima Medical Center (file number \nW19.080).\nStudy subjects\nPatients were recruited at the gynecological outpatient \nclinic between May 2020 and July 2023.\nThe inclusion criteria were: (1) premenopausal and \naged ≥ 18 years old; (2) diagnosis with endometriosis by \nphysical examination, ultrasound, MRI or laparoscopy; \n(3) presence of debilitating bowel symptoms such as \nabdominal pain, bloating, flatulence, constipation, diar -\nrhea, gurgling, urgency or nausea.\nThe exclusion criteria were: (1) postmenopausal or \naged < 18 years old; (2) not able to speak, read or write \nDutch; (3) gastro-intestinal co-morbidities such as food \nallergy, Crohn’s disease, Ulcerative Colitis, Coeliac dis -\nease; (4) diagnosis with Diabetes Mellitus; (5) currently \nfollowing another diet; (6) currently pregnant; and (7) \nplanned for endometriosis surgery during the research \nperiod.\nPatients meeting all the in- and exclusion criteria and \nwilling to participate, signed informed consent and \nreceived a referral to an affiliated dietitian afterwards. \nThe costs for guidance of the dietitian were covered by \nthe Máxima Medical Center. Participants could withdraw \nfrom the trial at any time. If endometriosis surgery did \noccur during the study period, patients were excluded \nfrom the time of surgery.\nIntervention\nAt baseline, all patients underwent an intake diet con -\nsultation by a trained FODMAP dietitian affiliated with \nthe study. During this consult detailed information about \nthe low-FODMAP diet was provided, including handouts \nwith recipes, tips, and meal plans. Thereafter, the diet \nstarted with the 4-week elimination period in which all \nFODMAPs were eliminated from the diet. During this \nperiod, the dietitian called the patient to monitor their \nprogress and answer questions. After completing the \nelimination period, patients were scheduled for a follow \nup consultation with the dietitian. Following the elimina -\ntion period, there was a reintroduction period in which \nthey reintroduced the FODMAPs that were restricted \nbefore. The FODMAPs were gradually reintroduced one \nat a time to identify specific triggers. The time required \nfor this phase was determined based on the need for par -\nticipants to adequately assess their responses and symp -\ntoms flare-ups to individual FODMAPs. Additionally, \npersonal circumstances, such as lifestyle or individual \npreferences, may have influenced the amount of time \nneeded for the reintroduction period. This period was \ntherefore variable between the participants, but lasted \nfor a minimum of 10 weeks. During the reintroduction \nperiod, multiple consultations took place, also depending \non the time required for this period. The diet was consid-\nered finished once both the elimination- and the reintro -\nduction period were completed, resulting in a minimum \nduration of 14 weeks. It was considered incomplete if \npatients themselves indicated that they had stopped \nthe diet and no longer attended appointments with the \ndietitian.\nPrimary and secondary outcomes\nThe primary outcome was constipation after the diet, i.e. \nafter the reintroduction period. The Constipation Scor -\ning System, as described by Agachan et al. [ 15], was cal -\nculated using the answers to the validated Groningen \nDeFeC questionnaire [ 16]. Constipation scores ranged \nfrom 0 to 30, with 0 indicating normal and 30 indicating \nsevere constipation. The secondary outcomes included \nbloating, QoL and abdominal pain post-diet. Bloating \nwas assessed using the Groningen DeFeC questionnaire \nand the following question that was asked after the diet: \n‘Did the diet improve your bowel symptoms? If yes, which \nsymptoms?’ QoL was measured by the Endometriosis \nHealth Profile-30 (EHP-30) [ 17]. The EHP-30 consisted \nof two parts: a core questionnaire, which is applicable \nto all patients with endometriosis, containing 30 items \nin five subscales (pain, control and powerlessness, emo -\ntional well-being, social support, and self-image) and a \nmodular questionnaire, which does not necessarily apply \nto all patients with endometriosis, containing 23 items \nin six subscales (work, relationship with children, sexual \nintercourse, medical profession, treatment, and infertil -\nity). Answers of EHP-30 can be rated on a 5-point scale \n(0 = never to 4 = always). The total scores range from 0 to \n100 with 0 indicating the best health status. Abdominal \npain was assessed using the ‘pain’ domain of the EHP-30. \nThis consists of 11 items that assess pain intensity and its \nimpact on social life, daily activities, sleep, movement, \nand eating. Furthermore, abdominal pain was assessed \nwith the following question that was asked after the diet: \n‘Did the diet improve your pain symptoms? If yes, which \nsymptoms?’ .\nAfter the diet, patients were contacted by the \nresearcher to answer additional questions about the diet. \nThese included the previous questions about bowel- and \npain symptoms, whether patients would recommend \nthe diet to other endometriosis patients, and the extent \nto which they adhered to the diet. Adherence to the diet \nwas measured by asking the question: ‘What percentage \ndid you deviate from the diet?’ The percentage calculated \nfrom this was used as a measure of non-adherence, indi -\ncating the extent to which participants did not strictly \nfollow the prescribed diet. Deviating from the diet was \ndefined as not adhering to the diet, such as consuming \nFODMAPs that should be avoided. Participants were also \nasked which FODMAPs they had reacted to. A reaction \n\nPage 4 of 8\nKeukens et al. BMC Women's Health          (2025) 25:174 \nwas defined as an increase in symptoms after reintro -\nducing a particular FODMAP . Electronic questionnaires \nwere sent by ResearchManager Electronic Data Capture \nsoftware at baseline, after the elimination period, and \nafter completing the diet. All data were derived from par-\nticipants’ self-reported responses to the questionnaires.\nSample size\nIt was not possible to perform a proper sample size cal -\nculation because of the absence of data on variability of \nthe outcomes. For this prospective pilot study we had \nchosen to include 30 patients in order to calculate a stan -\ndard deviation to be used in future studies and to be able \nto make an estimate of the clinical relevance of the out -\ncomes. During the study, we decided to include an addi -\ntional 17 patients due to an unexpectedly high dropout \nrate. In order to make more reliable conclusions on the \neffect of the fully completed diet, we decided to increase \nthe sample size.\nStatistical analysis\nThe Statistical Package for the Social Sciences (SPSS) \nversion 22 was used to perform statistical analyses [ 18]. \nDescriptive statistics were expressed as numbers with \npercentages for categorical data, medians with interquar -\ntile ranges (IQR) for non-normal distributed continuous \nvariables, and means with standard deviations (SD) for \nnormal distributed continuous variables.\nMean individual changes of primary and secondary \noutcomes after the diet compared to baseline were evalu -\nated using a paired T-test or Wilcoxon signed rank test. \nWe also performed an analysis on patients with avail -\nable data and who were loss to follow-up or who did not \ncomplete the diet for other reasons. Missing data were \nhandled using the listwise deletion method, where only \nparticipants with complete data for both baseline and \nfollow-up measurements were included in the analysis. \nP < 0.05 was considered significant.\nResults\nFrom June 2020 to July 2023, 47 patients were eligible and \ngave consent to participate in the study. Thirteen par -\nticipants withdrew before the start of the low-FODMAP \ndiet due to various reasons, shown in Fig.  1. One of the \nreasons was that surgical interventions occurred dur -\ning the research period. Another reason was that some \npatients eventually lacked the motivation or time to fol -\nlow a strict diet. Out of the remaining 34 participants, \n24 (71%) completed the diet. Ten participants discon -\ntinued the diet at various time points: seven after com -\npleting the elimination phase, one during the elimination \nphase after two weeks, and two during the reintroduction \nFig. 1 Flow diagram\n \n\nPage 5 of 8\nKeukens et al. BMC Women's Health          (2025) 25:174 \nphase, although the exact time point is unknown. We dis-\ntinguished between participants who completed the diet \nand those who discontinued it. (Fig.  1) Five participants \nwith baseline and post-elimination period data who did \nnot complete the diet were excluded, while two partici -\npants who completed the diet but did not submit their \nfinal questionnaire were included in the analysis.\nBaseline characteristics of the participants who com -\npleted the diet and who dropped out are shown in \nTable 1. There were no statistically significant differences \nbetween these two groups.\nThe participants who completed the diet reported sig -\nnificantly less constipation after the diet compared to \ntheir baseline scores with a mean difference of 2.1 (95% \nCI: 0.4–3.7, p = 0.023). There was no significant difference \nin experiencing bloating. A small decrease of experienc -\ning bloating appeared after the elimination phase, how -\never this was not significant ( p = 0.125). Better scores of \nall core domains of the EHP-30 questionnaire and ‘work \nlife’ and ‘sexual intercourse’ were reported after the diet \ncompared to their baseline scores. The mean differences \nwere 18.6 (95% CI: 7.6–29.6, p = 0.002) for ‘pain’ , 32.7 \n(95% CI: 21.9–43.5, p = 0.000) for ‘control and powerless-\nness’ , 16.1 (95% CI: 7.8–24.3, p = 0.001) for ‘emotional \nwell-being’ , 15.2 (95% CI: 3.0–27.3, p = 0.017) for ‘social \nsupport’ , 10.7 (95% CI: 0.8–20.6, p = 0.035) for ‘self-image’ , \n22.0 (95% CI: 9.6–34.3, p = 0.003) for work life and 17.7 \n(95% CI: 2.9–32.5, p = 0.023) for sexual intercourse. \n(Table 2) Within the group of participants who did not \ncomplete the diet, there were no significant differences \nfor constipation, experiencing bloated feeling and most \nQoL domains between follow-up after the elimination \nphase and baseline. There was only a significant worsen -\ning of the QoL domain ‘control and powerlessness’ (Wil-\ncoxon signed rank test statistic: -6.7 (95% CI: -11.3– -2.0, \np =.046). (Additional Table  1) We could not perform a \ntrustworthy comparison between groups who did and did \nnot complete the diet due to small numbers.\nOf the participants who started the diet, 63% agreed or \ncompletely agreed that the diet was easy to maintain. The \nmost common FODMAPS the participants had to elimi -\nnate were fructo-oligosaccharides and lactose. The par -\nticipants who completed the diet reported an average of \n8% non-adherence. 84% of them experienced a decrease \nin bowel symptoms and 53% experienced less bloating. \nAdditionally, 65% of them experienced less pain, espe -\ncially chronic pelvic pain. 50% continued the diet after \ncompleting the study, meaning they kept removing the \nFODMAPs they reacted to from their diet. Finally, the \nmajority of all participants found the low-FODMAP diet \na good addition to current therapies for endometriosis \n(87%) and would recommend the diet to other patients \nwith endometriosis and bowel symptoms (90%). (Addi -\ntional Table 2)\nDiscussion\nThis study aimed to evaluate the effect of the low-FOD -\nMAP diet on bowel symptoms such as constipation and \nbloating, QoL and abdominal pain in patients suffering \nfrom endometriosis. Our results demonstrate signifi -\ncant improvements in constipation scores and multiple \naspects of QoL, including ‘pain’ , among participants who \ncompleted the diet. Additionally, 65% of the participants \nexperienced less pain, especially chronic pelvic pain \nafter the diet. While the prevalence of bloating was not \ndifferent after the diet compared to baseline, 53% of the \nTable 1 Patient characteristics\nSample who \ncompleted the \ndiet\n(n = 24)\nSample who did \nstart, but did not \ncomplete the diet \n(n = 10)\np-\nval-\nue\nAge in years, M ± SD 32.5 ± 7.9 32.0 ± 7.4 0.866\nEducation, N (%)\nPrimary Education\nSecondary Education\nTertiary Education\nBachelor’s Degree\nMasters/ Doctoral \nDegree\n0\n2 (8.3)\n10 (41.7)\n9 (37.5)\n3 (12.5)\n0\n0\n6 (60)\n3 (30)\n1 (10)\n0.697\nBMI kg/m2, M ± SD 24.3 ± 4.7 26.6 ± 4.3 0.226\nLifestyle, N (%)\nCurrent smoker\nCurrent use of any \nalcohol\n1 (5.6)\n10 (55.6)\n1 (12.5)\n7 (77.8)\n0.529\n0.244\nEndometriosis, N (%)\nSuperficial\nEndometrioma\nDIE\nEndometrioma + DIE\n11 (45.8)\n6 (25)\n11 (45.8)\n2 (8.3)\n3 (30)\n1 (10)\n6 (60)\n0\n0.498\n0.315\n0.452\n0.338\nMedical history, N (%)\nUterus extirpation\nBowel or anus surgery\n3 (12.5)\n4 (16.7)\n1 (10)\n0\n0.682\n0.229\n(Anamnestically) diag-\nnosed with IBS, N (%)\n9 (37.5) 4 (40) 0.594\nROME III at baseline, \nN (%)\nIBS\nFunctional \nconstipation\n14 (58.3)\n4 (16.7)\n5 (50)\n4 (40)\n0.471\n0.154\nCurrent treatment, \nN (%)\nCombined oral \ncontraceptives\nProgesteron only pill\nLevonorgestrel IUD\nNuvaRing\nGnRH agonist\nPain medication\nNo medication\n3 (12.5)\n3 (12.5)\n0\n1 (4.2)\n0\n3 (12.5)\n14 (58.3)\n0\n0\n0\n0\n2 (20)\n3 (30)\n50 (50)\n0.338\n0.338\n0.706\n0.080\n0.228\n0.656\nM: mean, SD: standard deviation, DIE: deep infiltrating endometriosis, \nIBS: Irritable bowel syndrome, IUD: intrauterine device, GnRH agonist: \ngonadotropin-releasing hormone agonist\n\nPage 6 of 8\nKeukens et al. BMC Women's Health          (2025) 25:174 \npatients that completed the diet answered that they did \nexperience less bloating.\nPatients who did not complete the diet showed a sig -\nnificant worsening in the ‘control and powerlessness’ \ndomain. When patients completed the diet, in this \nspecific domain of QoL the largest improvement was \nobserved. This result suggests that following the diet \nempowers patients to take an active role in managing \ntheir symptoms. This aligns with previous studies that \nsuggested that self-management strategies have a positive \neffect on QoL by helping patients to have control over \ntheir disease [19]. \nOur findings are consistent with previous research \nthat has demonstrated the effectiveness of a low-FOD -\nMAP diet in alleviating bowel symptoms among patients \nwith endometriosis [ 13, 14, 20, 21]. A study on the low-\nFODMAP diet for patients with endometriosis and/or \nIBS found significant improvement in bowel symptoms \nfor patients with both IBS and endometriosis, with 72% \nshowing more than 50% bowel symptom reduction com -\npared to 49% in those with IBS alone [ 13]. Additionally, a \nrecent prospective study showed that compared to their \nbaseline pain scores, participants adhering to a diet (low-\nFODMAP or endometriosis diet) reported significantly \nless non-cyclical deep dyspareunia, cyclical dysuria, \nbloating, and tiredness in endometriosis patients after six \nmonths [14]. Almost half (44%) of 484 respondents with \nendometriosis in an Australian cross-sectional study on \nself-management options reported making dietary modi -\nfications, such as eliminating gluten, dairy, and/or FOD -\nMAPs. They noted significant improvements in pelvic \npain, gastrointestinal symptoms, and fatigue [ 20]. Aside \nfrom anecdotal reports in our study, we were unable to \ndemonstrate a significant effect on bloating, which con -\ntrasts with earlier results [ 14]. Previous research has \nshown that patients with endometriosis following the \nlow-FODMAP diet reported improvements in three out \nof eleven QoL domains after 6 months compared to their \nbaseline [14]. Our study demonstrated improvements in \nQoL in seven out of eleven domains. All contributing to \nfurther evidence to support the therapeutic benefits of \nthe low-FODMAP diet.\nTable 2 Influence of low FODMAP diet on constipation, bloated feeling and quality of life\nBaseline\nn = 24\nAfter elimination phase\nn = 19\nAfter reintroduction \nphase\nn = 21\nP-value: base-\nline vs. after \nreintroduc-\ntion phase\nConstipation (0–30)§\nMedian (IQR)\n7.0 (5) 6.0 (5) 5.0 (4) 0,0231\nBloated feeling, N (%) 24 (100) 15 (78.9) 21 (100) 0\nEHP-30 pain (0-100)±\nM ± SD\n47.8 ± 20.1 35.8 ± 19.1 29.2 ± 17.3 0.002\nEHP-30\ncontrol & powerlessness (0-100)±\nM ± SD\n69.4 ± 14.1 52.4 ± 25.8 36.7 ± 27.1 0.000\nEHP-30 emotional well-being (0-100)±\nM ± SD\n45.2 ± 21.1 33.1 ± 24.2 29.2 ± 23.2 0.001\nEHP-30 social support (0-100)±\nM ± SD\n46.4 ± 27.9 37.2 ± 18.7 31.3 ± 24.3 0.017\nEHP-30 self-image (0-100)±\nM ± SD\n51.2 ± 28.5 45.6 ± 27.7 40.5 ± 29.0 0.035\nEHP-30 work life (0-100)±\nM ± SD\n35.0 ± 27.4\n(n = 22)\n26.2 ± 25.5\n(n = 17)\n21.7 ± 23.2\n(n = 15)\n0.003\n(n = 15)2\nEHP-30 children (0-100)±\nMedian (IQR)\n25.0 (25.0)\n(n = 7)\n27.1 (40.6)\n(n = 6)\n25.0 (43.8)\n(n = 5)\n0.3171\n(n = 5)2\nEHP-30 sexual intercourse (0-100)±\nM ± SD\n61.6 ± 23.7\n(n = 19)\n54.0 ± 31.0\n(n = 15)\n45.7 ± 33.3\n(n = 14)\n0.023\n(n = 13)2\nEHP-30 medical profession (0-100)±\nMedian (IQR)\n18.8 (64.1) 12.5 (43.8) 0.0 (28.1) 0.1321\nEHP-30 treatment (0-100)±\nM ± SD\n36.7 ± 28.7\n(n = 20)\n41.7 ± 27.7\n(n = 14)\n30.1 ± 32.4\n(n = 13)\n0.389\n(n = 12)2\nEHP-30 infertility (0-100)±\nMedian (IQR)\n65.6 (40.6)\n(n = 10)\n62.5 (43.8)\n(n = 7)\n37.5 (75.0)\n(n = 11)\n0.7151\n(n = 7)2\nEHP-30: Endometriosis Health Profile 30, M: mean, IQR: interquartile range\n§ 0 indicating normal, ± 0 indicating best health status\n1: Calculated using Wilcoxon Signed Ranks Test\n2: Number of participants having data available both at baseline and after reintroduction phase\n\nPage 7 of 8\nKeukens et al. BMC Women's Health          (2025) 25:174 \nIt should be kept in mind that in this study a large \nproportion (28%) of patients who were supposed to \nstart the diet eventually did not start due to various rea -\nsons, including the lack of motivation and time. Also, 8 \nout of 34 patients stopped the diet because it appeared \nto be ineffective for them. The dropout is a good reflec -\ntion of daily care, though, as it proves to be difficult to \nget (and keep) patients fully motivated to follow a strict \ndiet. The adherence to the diet is important to maximize \nthe effect of the diet [ 14]. In our study, adherence was \nhigh, with an average non-adherence rate of 8% among \nthose who completed the diet. Although some patients \nhave not completed the diet, they would still recommend \nit for patients with endometriosis and bowel symptoms \nbecause according to them it is accessible and has no \nharmful effects. To enhance motivation, combining diet \ntherapy with psycho-education might be beneficial. This \napproach is currently being studied in a randomized con-\ntrolled trial in Nijmegen, the Netherlands. (Clinicaltrials.\ngov: NCT06332560) [22].\nAn important motivation for conducting this study \nwas that patients with endometriosis were engaging \nin self-management treatments despite the lack of evi -\ndence. Before offering and advising this diet to patients \nin clinical practice, we wanted to investigate effective -\nness. When we began our research, this was the first reg -\nistered prospective study examining the effects of the low \nFODMAP diet on patients with endometriosis. Recently \nanother study has been published, and our work now \nadds valuable evidence to this field. Although the stud -\nies show similarities, our study demonstrates a large \ndropout. An important aspect of our study was the refer -\nral to dietitians who were not part of the research team. \nWhile this approach could have led to a larger dropout, \nit mirrors real-world scenarios more accurately, as it \nreflects common practices where external dietitians are \noften involved. Consequently, the outcomes of our study \nmight be more representative of the results that could be \nexpected following implementation.\nDespite the promising results obtained from our \nstudy, several limitations should be acknowledged. Our \nfinal sample size was small, especially after eliminating \npatients who did not complete the diet. However, dem -\nonstrating a large proportion of participants who did \nnot start or continue the diet importantly reflects a sig -\nnificant outcome and is likely representative of daily care \nof patients with endometriosis. Nonetheless, the limited \nnumber of participants makes it challenging to explore \nfactors and/or confounders, like concurrent use of hor -\nmonal medication, type of endometriosis and sever -\nity of pain, which may have influenced diet completion \nand effectiveness. The absence of a control group in our \nstudy complicates the ability to rule out potential placebo \neffects. Another limitation is the potential influence of \nmaturation effects, as natural changes over time, regard -\nless of the intervention, could have contributed to the \nobserved outcomes. We did not measure pain using a \nstandardized score such as the numeric rating scale or \nthe visual analogue scale. Instead, we asked a question \nabout overall pain as recommended by Core Outcome \nMeasures in Effectiveness Trials (COMET initiative), \nbut which is still a work in progress [ 23]. When patients \nreported improvement in pain, we attempted to specify \nit further. Additionally, we assessed pain as an aspect of \nQoL, however this measures pain interference rather \nthan pain intensity. Finally, this pilot study had a follow-\nup duration similar to the diet duration itself. It would \nbe interesting to investigate the effects over an extended \nperiod in the participants that continued the diet after \nthe study period.\nThese limitations underscore the need for future \nresearch to address these shortcomings. A larger-scale \nstudy with a control group is necessary to confirm the \nefficacy of the low-FODMAP diet in endometriosis \npatients. Additionally, a longer follow up period would \nprovide valuable insights. Also, exploring the potential \nsynergistic effects of combining the low-FODMAP diet \nwith other treatment modalities could lead to more com -\nprehensive management strategies for endometriosis.\nIn conclusion, although the potential benefits and \nharms are still unclear, non-medical management strat -\negies are widely used by patients with endometriosis \n[24]. This study provides preliminary evidence for the \npotential benefits of the low-FODMAP diet in manag -\ning constipation, pain and improving QoL in patients \nwith endometriosis and who are motivated to adhere to \na diet. Our findings highlight the importance of consider-\ning dietary interventions as part of a holistic approach to \nendometriosis management. For an evidence-based rec -\nommendation adequately designed trials are needed.\nAbbreviations\nFODMAP  Fermentable Oligo-, di-, mono-saccharides, and polyols\nIBS  Irritable Bowel Syndrome\nEHP-30  Endometriosis Health Profile-30\nQoL  Quality of Life\nSupplementary Information\nThe online version contains supplementary material available at  h t t p  s : /  / d o i  . o  r \ng /  1 0 .  1 1 8 6  / s  1 2 9 0 5 - 0 2 5 - 0 3 7 1 5 - 1.\nSupplementary Material 1\nSupplementary Material 2\nAcknowledgements\nWe are thankful to all patients who participated in the study and the \ndieticians: Marion Theuws, Nicole Broeren, and Suzanne Blom for their \nguidance.\n\nPage 8 of 8\nKeukens et al. BMC Women's Health          (2025) 25:174 \nAuthor contributions\nAK, VV, MvdK, MB, SC and JM conceptualized the specific research questions \nand analytic approach for this manuscript. Analyses were conducted by AK. \nRecruitment of participants was done by AK, VV, MvdK, SC, MB and JM. AK \nwrote the first draft of the manuscript, and all authors edited and revised the \nmanuscript. All authors read and approved the final manuscript.\nFunding\nThis study was funded by the Science Fund of Máxima Medical Center \nVeldhoven, the Netherlands.\nData availability\nData is provided within the manuscript or supplementary information files.\nDeclarations\nEthics approval and consent to participate\nThe study was registered prospectively on September 13th 2019 in the Dutch \nTrial Register (NL8022) ( h t t p  s : /  / o n d  e r  z o e  k m e  t m e n  s e  n . n  l / e  n / t r  i a  l / 5 2 4 5 6) and \nwas conducted according to the principles of the Declaration of Helsinki and \napproved by the National Central Committee on Research involving Human \nSubjects (NL71354.015.19) and the medical ethical research committee of \nthe Máxima Medical Center (file number W19.080). Informed consent was \nobtained from all individuals included in this study. Date of first approval: 21th \nof January, 2020 and date of first participant enrollment: 27th of May, 2020.\nConsent for publication\nNot applicable.\nCompeting interests\nThe authors declare no competing interests.\nAuthor details\n1Department of Gynecology, Máxima Medical Center, Veldhoven, The \nNetherlands\n2GROW– Research Institute for Oncology and Reproduction, Maastricht, \nThe Netherlands\n3Department of Obstetrics and Gynaecology, Maastricht University \nMedical Center+, Maastricht, The Netherlands\n4Stichting Beroeps Opleiding Huisartsen (SBOH), Maastricht University, \nMaastricht, The Netherlands\nReceived: 17 December 2024 / Accepted: 4 April 2025\nReferences\n1. Johnson NP , Hummelshoj L, Adamson GD, Keckstein J, Taylor HS, Abrao MS, \nBush D, Kiesel L, Tamimi R, Sharpe-Timms KL, et al. World endometriosis \nsociety consensus on the classification of endometriosis. Hum Reprod. \n2017;32(2):315–24.\n2. Maroun P , Cooper MJ, Reid GD, Keirse MJ. 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