Preoperative Pelvic Pain Research Articles

Preoperative Pelvic Pain Syndromes Are a Risk Factor for Failure in Patients Undergoing Radiofrequency Endometrial Ablation

Preoperative Pelvic Pain Syndromes Are a Risk Factor for Failure in Patients Undergoing Radiofrequency Endometrial Ablation

The impact of preoperative pelvic pain on outcomes after vaginal reconstructive surgery

Pelvic pain is a debilitating condition that is common among women with pelvic floor disorders. Limited information is known about the impact of preoperative pelvic pain on outcomes after vaginal reconstructive surgery. This study aimed to compare the outcomes after vaginal reconstructive surgery between women with and without preoperative pelvic pain. Baseline and postoperative data were analyzed from the "Outcomes Following Vaginal Prolapse Repair and Midurethral Sling trial." The multicenter trial involved women with anterior prolapse without symptoms of stress incontinence randomized to receive either a midurethral sling or sham incisions during a vaginal reconstructive surgery. Participants completed the visual analog scale adapted for suprapubic pain and Pelvic Floor Distress Inventory at baseline, 3 months, and 12 months. Preoperative pelvic pain was defined as a response of "5" or greater on pain on the visual analog scale or answering "moderately" or "quite a bit" on the Pelvic Floor Distress Inventory question, "Do you usually experience pain in the lower abdomen or genital area?" Outcomes and complication rates were compared between women with and without pelvic pain. The "Outcomes Following Vaginal Prolapse Repair and Midurethral Sling trial" participants included 112 women with pelvic pain (58 had a midurethral sling and 54 had sham incisions) and 212 women without pelvic pain (105 had a midurethral sling and 107 had sham incisions). Women who had a midurethral sling and pelvic pain were younger than women without pelvic pain (60.3±12.1 vs 65.1±8.6; P=.004). Women who had sham incisions and pelvic pain were more likely of Hispanic ethnicity than women without pelvic pain (27.8% vs 9.4%; P=.002). Patient improvement based on the Patient Global Impression of Improvement scale did not differ between arms. Women with pelvic pain had greater improvement on the visual analog scale pain scores after a surgical procedure at 3 months (-3.1±2.9 vs-0.4±1.6; P<.001) and at 12 months (-3.4±3.0 vs-0.6±1.6; P<.001) than women without pain, although their pain scores remained higher than those without preoperative pelvic pain at all time points (P<.001 for all). Similar improvements were found on the Pelvic Floor Distress Inventory and Pelvic Floor Impact Questionnaire. The differences observed were not affected by whether women were in the midurethral sling or sham arm of the trial. Postoperative urinary tract infection and incomplete bladder emptying did not differ between the groups. Women with preoperative pelvic pain experienced significant improvements in pain and pelvic floor symptoms with vaginal reconstructive surgery and had similar subjective improvement postoperatively compared with women without preoperative pelvic pain. Reassuringly, the performance of a midurethral sling did not have an impact on the results.

13 The impact of preoperative pelvic pain on outcomes after vaginal reconstructive surgery

13 The impact of preoperative pelvic pain on outcomes after vaginal reconstructive surgery

Predictive Variables for Postoperative Opioid Requirements Following Hysterectomy

Study Objective To identify predictive factors for opioid consumption following hysterectomy by determining the relationship between perioperative opioid requirements, preoperative pelvic pain scores and patient variables. Design A prospective cohort study. Setting Canadian tertiary care academic center. Patients or Participants The study included 191 women undergoing hysterectomy. Interventions Preoperatively, all patients completed the Pain Sensitivity Questionnaire (PSQ), Pain Catastrophizing Scale and the Numeric Rating Scale (NRS). Cumulative opioid consumption (COC), calculated in oral morphine equivalents (OME), was the sum of opioid consumption recorded during three time periods; (i) intraoperatively, (ii) recovery room, and (iii) first 24 hours postoperatively. Measurements and Main Results 191 women underwent hysterectomy, 68 vaginal (36%), 91 laparoscopic assisted (48%), and 32 open (17%). The mean age and body mass index were 50 (27–77) and 27 (17-64) kg/m2, respectively. Most hysterectomies (138, 73%) were performed in premenopausal women. The majority of all hysterectomies were for benign indications (166, 87%), and 40 (21%) were pain-related. Median COC for all hysterectomies was 75 mg OME, and median 24h postoperative COC was 16 mg OME. In multivariate analysis, preoperative NRS scores, PSQ minor scores, preoperative use of pain medication and an open approach were found to be significant predictors of increased COC. Each additional point on the PSQ minor mean score and preoperative NRS score was found to be associated with an increase of 4 and 2.5 mg OME, respectively. Patients with open hysterectomy consumed 59.75 mg OME more than minimally invasive surgery patients, when all other factors were equal. Each additional preoperative pain medication was associated with a 9 mg OME increase. Conclusion Predictors of cumulative postoperative opioid requirements for hysterectomy include preoperative NRS scores, PSQ minor scores, number of preoperative pain medications, and surgical approach. This information can be used to create a predictive calculator to individualize perioperative interventions, optimize postoperative pain management, and tailor opioid use.

Preoperative quantitative sensory testing and robot-assisted laparoscopic hysterectomy for endometrial cancer: can chronic postoperative pain be predicted?

Objectives Chronic postoperative pain is prevalent after robot-assisted laparoscopic hysterectomy for endometrial cancer. Preoperative Quantitative Sensory Testing (QST) has been utilized to identify patients at risk of developing chronic postoperative pain after a range of surgical procedures. The aim of this prospective, observational study was to (1) determine the prevalence of chronic postoperative pain, (2) assess selected preoperative risk factors for chronic postoperative pain, and (3) evaluate if preoperative QST profiling could predict the development of chronic postoperative pain following robot-assisted laparoscopic hysterectomy for endometrial cancer. Methods One-hundred and sixty consecutive patients were included and handheld pressure algometry, cuff pressure algometry, temporal summation of pain, conditioned pain modulation, and heat pain thresholds were assessed prior to surgery. Patients were asked to fill out a questionnaire concerning pain in the pre- and post-operative time period six months after surgery. Chronic postoperative pain was defined as persistent, moderate to severe pain (mean visual analogue scale (VAS)≥3) on a daily basis six months after surgery. Results The prevalence of chronic postoperative pain after robot-assisted laparoscopic hysterectomy for endometrial cancer was of 13.6% (95% CI 8.4-20.4%). Patients that would develop chronic postoperative pain had a lower BMI (p=0.032), a higher prevalence of preoperative pelvic pain (p<0.001), preoperative heat pain hyperalgesia (p=0.043) and a higher level of acute postoperative pain (p<0.001) when compared to patients that would not develop chronic postoperative pain. A logistic regression model demonstrated that the presence of preoperative pelvic pain was a significant, independent predictive risk factor for development of chronic postoperative pain (OR=6.62, 95% CI 2.26-19.44), whereas none of the QST parameters could predict postoperative pain. Conclusions Preoperative QST assessment could not predict the development of chronic postoperative pain despite preoperative heat pain hyperalgesia in patients that would develop chronic postoperative pain.

2897 Sleep, Fatigue, and Life Satisfaction After Hysterectomy in Women with Preoperative Pain and Depression

Study Objective To examine differences in life satisfaction, sleep, and fatigue after hysterectomy among women with preoperative pelvic pain and/or depression. Design Secondary data analysis of a prospective, observational cohort study of women undergoing hysterectomy for benign conditions. Setting Academic tertiary care center. Patients or Participants 336 patients undergoing hysterectomy for benign indications. Interventions Patients completed validated assessments of life satisfaction, sleep, and fatigue preoperatively and 6-months after hysterectomy. Patients were divided into four groups based on preoperative characteristics: pelvic pain only, depression only, pain + depression, and no pain or depression. Presence of pelvic pain was defined as average pelvic pain score of ≥ 4 (on numerical rating scale 0-10) at baseline survey. Measurements and Main Results Preoperatively, women with pelvic pain only reported worse sleep (p=0.01) and fatigue (p At 6-month follow-up, women with pelvic pain only reported significant improvements in life satisfaction (p=0.04), sleep (p Conclusion Women with pre-existing pelvic pain only demonstrate improvements in life satisfaction, sleep disturbance, and fatigue following hysterectomy and achieve similar levels to those with no pain or depression. Women with coexisting depression fare significantly worse in these domains than those without.

2852 Long Term Follow up of Carbon Dioxide Laser Vaporisation Versus Harmonic Scalpel Excision in the Treatment of Superficial Endometriosis: A Randomised Controlled Trial

Study Objective To evaluate if excision of endometriosis (rAFS stages I-III) with the harmonic scalpel, is superior to carbon dioxide laser vaporisation in terms of symptoms over a 3 year period. Design This was a randomized double blind controlled trial. Setting Set at a Tertiary referral unit. Patients or Participants 116 patients found to have endometriosis at laparoscopy were randomized in to the study. Interventions The study was powered for superiority, and patient's randomized with a 1:1 allocation into receiving treatment either with laser or harmonic scalpel. Data was analyzed using SPSS version 21. The primary outcome measure was the visual analogue scale (VAS) score for chronic pelvic pain score at 6 months. Secondary outcomes included core EHP-30, HADS anxiety and depression score and VAS scores for chronic pelvic pain, dysmenorrhoea, dyschezia and dyspareunia, up to 3 years. Measurements and Main Results Pre operative chronic pelvic pain (VAS) for the laser and harmonic groups were 57.1 (IQR: 28.1-75.6) and 50.6 (IQR: 0-75.0) respectively, and at 6 months 43 (IQR: 0-66.5) and 30 (IQR: 0-60.7). The difference between the two were not statistically significant, p=0.228. At 12 months the chronic pelvic pain VAS scores for laser and harmonic groups were 50 (IQR: 20-74.7) and 13.1 (IQR: 0-49.0) respectively. The difference between the two was significant, p Conclusion Excision of endometriosis with harmonic is effective at improving chronic pelvic pain up to 3 years. This does not appear to be the case with CO2 laser vaporisation. In terms of most secondary outcomes laser performs as well as harmonic at 6 months but the trend is in favor of harmonic up to 3 years.

Pelvic Pain and Apical Prolapse Surgery: A Population-Based Retrospective Cohort Study.

The aims of this study were to evaluate the association of preoperative pelvic pain with operative characteristics and the association of patient and operative characteristics with postoperative pain. This is a retrospective cohort study utilizing Clinformatics DataMart, a large national commercial insurance database. We collected data for patients older than 18 years who underwent apical prolapse surgery between January 2005 and December 2014. We stratified data by preoperative (prior) pain and analyzed for associations of prior and postoperative pain. Logistic regression analysis was performed using SAS software. A total of 14,440 patients met inclusion criteria and were analyzed. Patients with prior pain were more likely to have an abdominal (open or laparoscopic) approach, a concomitant hysterectomy, but less likely to have additional repairs or a mesh insertion (P < 0.001). Postoperative pain was less with a concomitant hysterectomy, whether they had prior pain (odds ratio [OR], 0.56; 95% confidence interval [CI], 0.41-0.77) or not (OR, 0.68; 95% CI, 0.56-0.82). Additional vaginal repairs were associated with more postoperative pain for those without prior pain (OR, 1.63; 95% CI, 1.3-2.04). Age older than 45 years was associated with less pain. Length of hospital stay of more than 2 days was associated with more pain. Patients with prior pain were more likely to undergo an abdominal approach and have a concomitant hysterectomy. Postoperative pain was less with a concomitant hysterectomy, but more with additional vaginal repairs. There is a need to include pain as an outcome in future studies, particularly clinical trials.

Systematic review of outcomes following pelvic exenteration for the treatment of primary and recurrent locally advanced rectal cancer.

Pelvic exenteration represents the best treatment option for cure of locally advanced or recurrent rectal cancer. This systematic review sought to evaluate current literature regarding short and long term treatment outcomes and long term survival following pelvic exenteration. A systematic search of the MEDLINE, PubMed and Ovid databases was conducted to identify suitable articles published between 2001 and 2016. The article search was performed in line with Cochrane methodology and reported according to the Preferred Reporting Items for Systematic reviews and Meta-analyses statement. Sixteen studies were included in the final analysis, incorporating 1016 patients. Sixty-three percent of patients were male and median patient age was 59years. Median operating time was 7.2h with median blood loss of 1.9l. Median postoperative stay was 17days with a median 30-day mortality of 0. Complication rates were 31.6-86% with a return to theatre rate of 14.6%. Median R0 resection rate was 74% and was higher for primary cancer (82.6% versus 58% for recurrent cancer). Mean overall survival was 31months and median 5-year survival was 32%. Recurrently identified indicators of adverse outcome included R1/2 resection, preoperative pelvic pain and previous abdominoperineal resection of the rectum. Pelvic exenteration remains a major operation associated with significant morbidity and mortality. Despite advances in preoperative assessment and staging, R1 resection rates remain high. There is also a high degree of variability of reporting outcomes and standardisation of this process would aid comparison of results between centres and drive forward research in this area.

Chronic pain after hysterectomy

Hysterectomy is a common surgical procedure with a low risk of major complications. However, some women experience long-lasting complications, including chronic postsurgical pain, which can have a negative impact on their quality of life. This review aims to present the recent literature on chronic pain following hysterectomy for benign indications. Chronic pain following hysterectomy is reported in 10-50% of women. Risk factors include preoperative pelvic pain, pain elsewhere, acute postoperative pain, surgical procedure, and psychological factors such as anxiety and depression. The pain may be neuropathic in 5-50% of cases. Chronic pain may occur after hysterectomy. Preoperative screening tools, including psychological screening for depression and anxiety, may identify women at risk of developing chronic postsurgical pain, and future studies should examine perioperative interventions aimed at preventing the development of chronic pain after hysterectomy.

The Effect of Uterine Size on the Failure Rate of NovaSure Radiofrequency Endometrial Ablation [11D

INTRODUCTION: Utilization of NovaSure endometrial ablation has been shown to be successful in treating menorrhagia. Little data exists describing NovaSure ablation failure. The purpose of this research is to determine variables most predictive of failure with NovaSure endometrial ablation. METHODS: A retrospective case-control study included 224 women who received NovaSure ablation between 2003-2014 at Memorial University Medical Center. 112 of these patients were identified as failures receiving a subsequent hysterectomy and the other 112 women were identified as control patients without a need for subsequent hysterectomy. Patient charts were accessed and reviewed to determine uterine measurements and the preoperative status of each woman including pre-operative pain and prior bilateral tubal ligation. Using SPSS Statistical software, the data was analyzed. RESULTS: Mean uterine sound (p= 0.043) and mean cervical length (p= 0.049) were predictive of failure. Secondary analyses determined women with prior bilateral tubal ligation (p= 0.009) predicted failure with NovaSure ablation. Women who experienced preoperative pelvic pain trended toward failure requiring subsequent hysterectomy, but no statistically significant difference was noted (p= 0.073). CONCLUSION: Within the limitations of this study, a NovaSure ablation in women with a longer uterus and a longer cervix yields higher failure rates with subsequent hysterectomy. The data also supports the hypothesis that the presence of tubal sterilization is associated with increased risk of subsequent hysterectomy. Determining the significance of pre-operative pain will require further chart investigation. This study can help physicians better identify NovaSure ablation candidates that will be successful thereby improving cost efficacy.

Hysteroscopic management of displaced levonorgestrel‐releasing intrauterine system

This study was designed to evaluate feasibility and effectiveness of hysteroscopic intervention in the management of symptoms related to the displaced levonorgestrel-releasing intrauterine system (LNG-IUS). One hundred and thirteen patients with displaced LNG-IUS presenting with irregular uterine bleeding, pelvic pain or asymptomatic displacement were recruited for hysteroscopic examination. Displaced LNG-IUS was relocated by hysteroscopic intervention and the effect on symptoms and LNG-IUS position was followed. The displaced LNG-IUS was successfully relocated by hysteroscope in 112 (99.1%) of 113 cases. Following LNG-IUS relocation, 71 (79.8%) patients of 89 with preoperative irregular uterine bleeding had amenorrhea or vaginal spotting, and 14 of 15 (93.3%) patients with preoperative pelvic pain became asymptomatic. LNG-IUS expulsion was recorded in two patients 7 and 21 days after hysteroscopy. Displaced LNG-IUS can cause clinical symptoms (e.g. irregular bleeding, pain). Hysteroscopic relocation of displaced LNG-IUS is a feasible method in the management of these symptoms. Risk of spontaneous expulsion associated with hysteroscopy is low.

Impact of Perioperative Pain Intensity, Pain Qualities, and Opioid Use on Chronic Pain After Surgery

A better understanding of the pathogenesis of chronic postsurgical pain is needed in order to develop effective prevention and treatment interventions. The objective of this study was to evaluate the incidence and risk factors for chronic postsurgical pain in women undergoing gynecologic surgery. Pain characteristics, opioid consumption, and psychologic factors were captured before and 6 months after surgery. Analyses included univariate statistics, relative risks (RRs) and 95% confidence intervals (95% CIs), and modified Poisson regression for binary data. Pain and pain interference 6 months after surgery was reported by 14% (n = 60/433) and 12% (n = 54/433), respectively. Chronic postsurgical pain was reported by 23% (n = 39/172) with preoperative pelvic pain, 17% (n = 9/54) with preoperative remote pain, and 5.1% (n = 10/197) with no preoperative pain. Preoperative state anxiety (RR = 1.8; 95% CI, 1.1-2.8), preoperative pain (pelvic RR = 3.7; 95% CI, 1.9-7.2; remote RR = 3.0; 95% CI, 1.3-6.9), and moderate/severe in-hospital pain (RR = 3.0; 95% CI, 1.0-9.4) independently predicted chronic postsurgical pain. The same 3 factors predicted pain-interference at 6 months. Participants describing preoperative pelvic pain as "miserable" and "shooting" were 2.8 (range, 1.3-6.4) and 2.1 (range, 1.1-4.0) times more likely to report chronic postsurgical pain, respectively. Women taking preoperative opioids were 2.0 (range, 1.2-3.3) times more likely to report chronic postsurgical pain than those not taking opioids. Women with preoperative pelvic pain who took preoperative opioids were 30% (RR = 1.3; 95% CI, 0.8-1.9) more likely to report chronic postsurgical pain than those with preoperative pelvic pain not taking opioids. Preoperative pain, state anxiety, pain quality descriptors, opioid consumption, and early postoperative pain may be important predictors of chronic postsurgical pain, which require further investigation.

Mechanosensitivity before and after hysterectomy: a prospective study on the prediction of acute and chronic postoperative pain

The incidence of chronic pain after hysterectomy is reported to be up to 30%, but the relative role of different pathogenic factors has not been defined. This study aimed to assess the predictive value of preoperative abdominal and vaginal mechanosensitivity for the subsequent development of acute and chronic pain after hysterectomy. Ninety women undergoing hysterectomy for benign conditions were studied. Experimental testing was carried out on the day before hysterectomy, on the first postoperative day, and after 4 months. Abdominal testing included brush-evoked allodynia, pinprick hyperalgesia, wind-up-like pain, and pressure pain thresholds. Vaginal testing included pressure pain thresholds. The intensity of pelvic pain was recorded on a numerical rating scale before hysterectomy, daily in the first postoperative week, and after 4 months. The incidence of pelvic pain was 51% before hysterectomy and 17% after 4 months. Before hysterectomy, brush-evoked allodynia and pinprick hyperalgesia were more frequent in women with pelvic pain (P=0.04 and 0.02, respectively), with abdominal and vaginal pressure pain thresholds being lower in those with preoperative pelvic pain (P=0.04 and <0.01, respectively). Preoperative brush-evoked allodynia, pinprick hyperalgesia, and vaginal pressure pain threshold were associated with the intensity of acute postoperative pain (P=0.04, <0.01, and <0.01, respectively). Preoperative brush-evoked allodynia was also associated with pelvic pain after 4 months (P<0.01). Preoperative pain sensitization as reflected by cutaneous and vaginal hypersensitivity is associated with acute pain after hysterectomy, but less so with persistent pain.

Risk Factors for Chronic Pain after Hysterectomy

Women scheduled to undergo hysterectomy for benign indications frequently have preoperative pelvic pain, but it is largely unknown why pain in some cases persists or even develops after surgery. This nationwide questionnaire and database study describes pain and identifies risk factors for chronic postsurgical pain 1 yr after hysterectomy for benign indications. A pain questionnaire was mailed to 1,299 women 1 yr after hysterectomy. The response rate was 90.3%, and the presence of persistent pain was correlated to indication for surgery, surgical procedure, type of anesthesia, and other perioperative data. Pain was reported by 31.9% 1 yr after hysterectomy (chronic pain), and 13.7% had pain more than 2 days a week. Pain was not present before surgery in 14.9% of women with chronic postsurgical pain. Risk factors for chronic pain were preoperative pelvic pain (odds ratio [OR], 3.25; 95% confidence interval [CI], 2.40-4.41), previous cesarean delivery (OR, 1.54; CI, 1.06-2.26), pain as the main indication for surgery (OR, 2.98; CI, 1.54-5.77), and pain problems elsewhere (OR, 3.19; CI, 2.29-4.44). Vaginal hysterectomy versus total abdominal hysterectomy was not significantly associated with a lower risk of chronic pain (OR, 0.70; CI, 0.46-1.06). Importantly, spinal versus general anesthesia was associated with less chronic pain (OR, 0.42; CI, 0.21-0.85). Thirty-two percent had chronic pain after hysterectomy, and risk factors were comparable to those seen in other operations. Interestingly, spinal anesthesia was associated with a lower frequency of chronic pain, justifying prospective study of spinal anesthesia for patients with a high risk for development of chronic postsurgical pain.

Quality of life and sexual function after hysterectomy in women with preoperative pain and depression.

We sought to examine differences in quality of life and sexual function after hysterectomy among women with preoperative pain and depression. We analyzed data from a cohort study of 1,249 women who had hysterectomies for benign conditions. Participants were interviewed, before surgery and at 5 intervals after, regarding pelvic pain, depression, quality of life, and sexual function. We compared quality of life and sexual function at 6 and 24 months among women with preoperative pelvic pain alone, depression alone, both pelvic pain and depression, or neither. At 24 months, women with pain and depression had reduced prevalence of pelvic pain (96.7% decreased to 19.4%), limited physical function (66.1% to 34.3%), impaired mental health (93.3% to 38.1%), and limited social function (41.1% to 15.1%). Women with pain only improved in pelvic pain (95.1% to 9.3%) and limited activity level (74.3% to 24.2%). The group with depression only had improvement in impaired mental health (85.1% to 33.1%). Dyspareunia decreased in all groups. Compared with women who had neither pain nor depression, women with depression and pain had 3 to 5 times the odds of continued impaired quality of life: odds ratio (OR) 2.73, 95% confidence interval (CI) 1.78-4.19 for limited physical function; OR 3.41, 95% CI 2.13-5.46 for impaired mental health; OR 5.76, 95% CI 2.79-11.87 for limited social function; OR 4.91, 95% CI 2.63-9.16 for continued pelvic pain; and OR 2.41, 95% CI 1.26-4.62 for dyspareunia. Women with pelvic pain and depression fare less well 24 months after hysterectomy than women who have either disorder alone or neither. Nevertheless, these women improve substantially over their preoperative baseline in all the quality of life and sexual function areas assessed. II-2

Predicting treatment choice for patients with pelvic organ prolapse.

To evaluate which clinical factors were predictive of treatment choice for patients with pelvic organ prolapse. One hundred fifty-two patients were enrolled in this cross-sectional study to collect clinical data on potential predictors of treatment choice. Continuous parametric, continuous nonparametric (ordinal), and categoric data were compared with chosen management plan (expectant, pessary, surgery) using analysis of variance, the Kruskal-Wallis test, and the chi(2) test for association, respectively. All significant predictors (P <.05) of treatment choice for pelvic organ prolapse identified during univariate analysis were entered into a backward elimination polytomous logistic regression analysis for predicting surgery versus pessary versus expectant management, with surgery as the reference group. The probability of choosing expectant management rather than surgery 1). increases as the preoperative pelvic pain score increases (odds ratio [OR] 1.6; 95% confidence interval [CI] 1.07, 2.40; P =.024) and 2). decreases as the prolapse severity increases (OR 0.46; 95% CI 0.29, 0.72; P =.001). The probability of choosing pessary rather than surgery 1). increases as age increases (OR 1.1; 95% CI 1.05, 1.16; P <.001), 2). decreases as the prolapse severity increases (OR 0.77; 95% CI 0.60, 0.99; P =.042), and 3). is less if the participant had prior prolapse surgery (OR 0.23; 95% CI 0.07, 0.76; P =.017). Age, prior prolapse surgery, preoperative pelvic pain scores, and pelvic organ prolapse severity were independently associated with treatment choices in a predictable way and provide physicians with medical evidence necessary to support a patient's decision.

Pretreatment of the primigravid uterine cervix with mifepristone 30 h prior to termination of pregnancy: a double blind study

To determine the effect of the antiprogestogen mifepristone (RU 486) on cervical resistance before first trimester termination of pregnancy. Prospective double blind randomized placebo controlled study. Department of gynaecology in a university teaching hospital, Sheffield. 80 Primigravid women greater than 18 years of age, undergoing termination of pregnancy at between 7 and 13 weeks gestation. A single dose of 600 mg of mifepristone or placebo given orally 30 h before termination of pregnancy under general anaesthesia. Cervical resistance to dilatation. Pretreatment with mifepristone significantly reduced the amount of force required to dilate the cervix to 10 mm. In comparison with placebo, the mean sum of the peak forces obtained with dilators 4 to 10 mm was reduced from 84.3 N (SD 29.7) to 46.0 N (SD 26.7). Two women in the treated group had a cervical resistance of greater than 100 N compared with nine women in the placebo group (RR 0.18, 95% CI 0.04-0.89). The 8 mm dilator could be passed with less than 5 N force in 16 women (43%) in the treated group compared with none in the placebo group. Women in the active treatment group had more preoperative pelvic pain and vaginal bleeding but less postoperative pain. Mifepristone significantly reduces cervical resistance in the first trimester of pregnancy and produces minimal side effects.