Objective
The objective of the study was to evaluate the efficacy and safety of global endometrial ablation in women with a history of cesarean delivery.
Study Design
We performed a historical cohort study of patients who underwent endometrial ablation for menorrhagia between 1998 and 2005. Outcome measures included amenorrhea, treatment failure, and operative complications. Time to treatment failure was compared using Kaplan-Meier analysis. Risk adjustments were performed using Cox and logistic regression models.
Results
Of 704 patients meeting inclusion criteria, 162 (23%) had a history of 1 or more cesarean deliveries. Women with and without a history of cesarean delivery had comparable rates for 5 year cumulative endometrial ablation failure, amenorrhea, treatment failure, and operative complications. The type of ablation device and number of previous cesarean deliveries did not affect any outcomes.
Conclusion
The efficacy and safety of endometrial ablation are comparable in women with or without a history of cesarean delivery.
Heavy menstrual bleeding, or menorrhagia, is a common condition that affects women of reproductive age and can result in anemia, chronic fatigue, and loss of work. In the United States and worldwide, heavy menstrual bleeding accounts for approximately 20% of office visits by women of reproductive age.
Endometrial ablation is an effective and safe procedure for treating heavy menstrual bleeding. Recently the American Congress of Obstetricians and Gynecologists has expressed concern about performing endometrial ablation in cases in which the myometrium can be thin, specifically after abdominal or laparoscopic myomectomy or cesarean delivery. Nevertheless, few well-designed studies have addressed the efficacy and safety of endometrial ablation in women who previously had a cesarean delivery. The goal of this study was to evaluate the safety and efficacy of global endometrial ablation (GEA) in women with a history of cesarean delivery.
Materials and Methods
This study was approved by the Mayo Clinic Institutional Review Board. We retrospectively searched our electronic medical record for the cases of women who underwent GEA at Mayo Clinic (Rochester, MN) from Jan. 1, 1998, through Dec. 31, 2005, by using the International Classification of Diseases, Ninth Revision , Clinical Modification (ICD-9-CM) code for endometrial ablation.
Patients were included only if they had given consent for research use of their medical records. There were no age limits or other exclusion criteria for included patients. Some of the patients included in this study were also included in our previous publications.
The study group was separated into 2 cohorts: patients who had had at least 1 cesarean delivery and patients who were either nulliparous or had only had vaginal deliveries in the past. Patients with a history of cesarean delivery were identified by using the relevant ICD-9-CM codes. All records were also reviewed individually to confirm a past surgical history of 1 or more cesarean deliveries.
The 2 methods for GEA used at the Mayo Clinic during the study period were thermal balloon ablation (Gynecare ThermaChoice; Ethicon, Somerville, NJ) and radiofrequency ablation (NovaSure; Hologic Inc, Bedford, MA). Before GEA, all included patients underwent an endometrial biopsy for sampling, a Papanicolaou test, pelvic ultrasonography, and in-office hysteroscopy if anatomical anomalies were suspected. GEA was offered only to patients with benign endometrial polyps or with submucous leiomyomas smaller than 2 cm in largest diameter or those that did not distort the endometrial cavity. Such polyps and leiomyomas were removed by dilation and curettage or ablation in situ.
No patients were pretreated with gonadotropin-releasing hormone agonists. Demographic data collected included age, body mass index, pattern of bleeding, parity, presence of dysmenorrhea, uterine length, and endometrial thickness.
Efficacy of the GEA procedure was assessed by rate of amenorrhea, which was defined as lack of bleeding from immediately after the procedure for a minimum of 12 months after the procedure. Rates of post-GEA treatment failure, defined as bleeding or pain after ablation that required hysterectomy or reablation, were also calculated and used as an outcome measure of efficacy. Patients with treatment failure were identified by using the relevant ICD-9-CM codes, and time to failure was measured; all records were also reviewed individually to confirm failure by documentation of repeat ablation or hysterectomy. For women without treatment failure, follow-up was censored at last contact or death before the end of the study period. The last date medical records were reviewed for patient follow-up was May 31, 2010.
To assess the safety of GEA in both cohorts, intraoperative complications and postoperative complications within 6 weeks of surgery were noted. Uterine perforation (the main intraoperative complication) was defined as any breach in uterine cavity integrity that precluded ablation or warranted additional surgical intervention. Anatomical sites of all uterine perforations were noted. Other potential intraoperative complications, including cervical lacerations, failure to complete the ablation cycle, bowel or bladder injury, allergies to local or general anesthetics, and complications from anesthesia, also were documented. Potential postoperative complications included urinary tract infections, endometritis, and allergic reactions to medications used during or after surgery.
Statistical analysis
Continuous data with normal distribution are given as mean (SD); the median and range are used for skewed data. Categorical data are given as number of patients (percentage). Baseline characteristics of the 2 cohorts were compared using the Student t test or Wilcoxon rank sum (Mann-Whitney) test for continuous variables, according to the distribution, and the χ 2 test or Fisher’s exact test was used for comparison of categorical variables, as appropriate.
Time to treatment failure was evaluated with Kaplan-Meier curves and tested with the log-rank test. The plots showing cumulative failure rates were used to calculate 5 year failure rates and corresponding 95% confidence intervals (CIs). The percentage of women with amenorrhea in each group was compared using the χ 2 test. Regression models were used to adjust for potential bias caused by known confounders. Similarly, for evaluation of postablation amenorrhea, logistic regression modeling was used to adjust for age, uterine length, and endometrial thickness. These variables were significantly associated with amenorrhea in our population.
Adjusted hazard ratios and odds ratios (ORs) were used to evaluate the likelihood of treatment failure and immediate amenorrhea. All statistical analyses were 2 sided, and P < .05 was considered significant. Statistical analyses were performed using JMP version 6.0 (SAS Institute, Inc, Cary, NC).
Results
Of 711 patients identified who underwent GEA between 1998 and 2005, documentation of the mode of delivery or of nulliparity was found for 704 patients. Of these 704 patients who made up the final cohort, 444 had radiofrequency ablation and 260 had thermal balloon ablation. The 162 patients who had a history of 1 or more cesarean deliveries (23%) were compared with the 542 patients who had no history of cesarean delivery. Patients in the cesarean group were younger, had higher parity, and more often had a history of tubal ligation than those in the group who did not have cesarean delivery. Other characteristics were comparable between the study groups ( Table ).
