A C TA Obstetricia et Gynecologica

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1 A C TA Obstetricia et Gynecologica AOGS MAIN RESEARCH ARTICLE Anti-M ullerian hormone reduction after ovarian cyst surgery is dependent on the histological cyst type and preoperative anti-m ullerian hormone levels TEKLA LIND 1, MARGARETA HAMMARSTR OM 2, CLAUDIA LAMPIC 3 & KENNY RODRIGUEZ- WALLBERG 1,4 1 Department of Clinical Science, Intervention and Technology (CLINTEC), Section for Obstetrics and Gynecology, Karolinska Institute, 2 Department of Clinical Science and Education, S odersjukhuset, Karolinska Institute, 3 Department of Neurobiology, Care sciences and Society, Karolinska Institute, and 4 Department of Obstetrics and Gynecology, Fertility Unit, Karolinska University Hospital, Stockholm, Sweden Key words Anti-M ullerian hormone, cyst enucleation, ovarian cyst surgery, ovarian reserve, prospective follow up Correspondence Tekla Lind, Karolinska Institutet, Department of Clinical Science, Intervention and Technology, Section for Obstetrics and Gynecology, Karolinska University Hospital Huddinge K57, Stockholm, Sweden. tekla.lind@sodersjukhuset.se Conflict of interest The authors have stated explicitly that there are no conflicts of interest in connection with this article. Please cite this article as: Lind T, Hammarstr om M, Lampic C, Rodriguez- Wallberg K. Anti-M ullerian hormone reduction after ovarian cyst surgery is dependent on the histological cyst type and preoperative anti-m ullerian hormone levels. Acta Obstet Gynecol Scand 2015; 94: Received: 1 April 2014 Accepted: 30 September 2014 DOI: /aogs Abstract Objective. To investigate changes in serum anti-m ullerian hormone (AMH) concentrations following ovarian cyst surgery, and predictors of these changes. Design. Prospective cohort study with follow up at 3 and 6 months. Setting. University hospital. Population. Women of reproductive age scheduled for ovarian cyst surgery. Methods. Women were recruited between March 2011 and March 2012 (n = 75). Serum AMH concentrations were measured preoperatively and at 3 and 6 months postoperatively. Main outcome measures. Changes in AMH after surgery and predictors for these changes. Results. After surgery, median AMH levels decreased significantly from 2.7 lg/ L ( ) to 1.6 lg/l ( ) at 3 months and were still low, 1.6 lg/l ( ) at 6 months (both p < 0.001). In patients with unilateral cysts, a significant and more rapid AMH decrease was seen after enucleation of endometriomas (n = 19) vs. dermoid cysts (n = 22) (p = 0.010). The reduction was long-lasting at 6 months. In a multivariate regression analysis, a higher baseline AMH concentration was predictive of AMH reduction at 3 [odds ratio (OR) 1.9, 95% CI ] and 6 months postoperatively (OR 2.5, 95% CI ). Women with normal or elevated baseline AMH presented with a significant reduction of 23% and 43% at 3 and 6 months, respectively, whereas women with low or very low AMH had minimal or no changes over time. Patient s age, cyst size, duration of surgery or intraoperative bleeding were not predictive of a postoperative AMH decrease. Conclusions. Reduction of AMH was of greater magnitude and longer duration after enucleation of endometriomas and in women with normal and high preoperative AMH levels. Abbreviations: AFC, antral follicular count; AMH, anti-m ullerian hormone. Introduction Ovarian cysts in women of reproductive age are common (1). In a study of a random sample of 335 women between 25 and 40 years of age, 8% presented with an abnormal finding on their ovaries (2). In Sweden, with a Key Message Women with endometriotic cysts presented with the largest decrease in postoperative anti-m ullerian hormone levels. Baseline anti-m ullerian hormone concentration was the only predictor for a reduction of anti-m ullerian hormone. This is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made. 183

2 AMH changes following ovarian surgery T. Lind et al. population of nine million people, 2781 ovarian cyst operations were registered in women of years of age in 2012, which indicates an incidence of 191/ (3). Conservative ovarian cystectomy (cyst enucleation) is the current preferred surgical intervention for the treatment of benign ovarian cysts in women of fertile age (4). Cyst enucleation techniques aim at being fertility-sparing, but there has been a debate recently concerning to what extent conservative surgery might still affect fertility, which has been suggested could be a result of unavoidable removal of normal ovarian tissue or surgical damage to the remaining normal ovarian tissue. Anti-M ullerian hormone (AMH) secreted by pre-antral and early antral follicles, is currently recognized as the best biochemical marker of ovarian reserve (5,6). Its progressive decline during reproductive life has been validated in large studies (7), as well as its stability in most women throughout the menstrual cycle (8). In this vein, studies have reported that a reduction of ovarian reserve may be quantified by measuring the serum concentration of AMH after ovarian surgery of endometriomas (9,10). In addition to biochemical markers of ovarian reserve, clinical outcomes after fertility treatments have also been studied to assess the impact of conservative ovarian cystectomy on ovarian reserve. A reduction in several parameters, such as number of oocytes retrieved after gonadotropin stimulation for in vitro fertilization, has been reported (9,11 16). Bilateral ovarian cystectomy has been recognized as the most important predictor for the AMH postoperative decline (10). Predictive factors in women with unilateral cysts have not yet being identified. The aim of our study was to prospectively investigate changes in serum AMH concentrations at 3 and 6 months following ovarian cyst surgery in women of reproductive age and to identify predictors for these changes. Variables investigated included age, cyst size, the histopathological type of cyst found, preoperative AMH concentrations and difficulties in surgical dissection estimated by intraoperative bleeding and duration of surgery, as surrogate parameters. Material and methods Women were included in this prospective cohort study from 14 March 2011 to 26 March 2012 when they were scheduled for conservative surgery of ovarian cysts at the Department of Obstetrics and Gynecology, S odersjukhuset, Stockholm, Sweden. The women were usually referred after a diagnosis of a symptomatic and persistent ovarian cyst, confirmed on at least three ultrasound examinations. Indications for cyst surgery included pain, a growing cyst, and in a few cases suspicion of cancer. At the initial consultation at our clinic, scheduled on the day before surgery, an additional transvaginal ultrasound was performed. In 19 women, antral follicular counts (AFC) were also assessed. Complete clinical information, including data on previous gynecological surgery, cyst size, surgical technique, and histopathological analyses, was obtained from the medical records. Serum AMH concentrations were assayed before surgery (baseline) and at 3 (2 weeks) and 6 (2 weeks) months after surgery. A postoperative gynecological visit was offered to the patients for estimation of AFC at 6 months, if the women wished it. Ethical approval from the Regional Ethics Committee in Stockholm, Sweden (d-nr 2011/ ) was obtained before the study. One hundred and twelve women, (mean age 32.4 years, range 18 43) and scheduled for elective or emergency ovarian cyst surgery were recruited. Women who discovered they were pregnant at the time of surgery or who became pregnant during the follow-up period were subsequently excluded (n = 12), as were women who did not attend follow-up visits (n = 10). In five cases, cysts were found to be malignant at the time of surgery, and these women were also excluded. Ten women were excluded because only fenestration without histopathology was performed. The remaining 75 women, who all presented with benign ovarian cysts that were histopathologically studied, are included in these analyses. Of them, 62 attended a 3-month follow-up visit, 67 attended a 6-month visit and 54 women had data for all three AMH measurements. The women underwent ovarian cyst surgery either by laparoscopy (n = 65) or laparotomy (n = 10). All surgical procedures were performed under general anesthesia by an experienced gynecologist. Laparoscopic surgery was performed as follows: pneumoperitoneum was induced with CO 2 using a Verres needle until 20 mmhg intraabdominal pressure was obtained. A 5-mm trocar with endoscope was introduced through an umbilical incision. In addition, two or three 5-mm trocars were inserted suprapubically. If there were no signs of malignancy the cyst cleavage plane was identified and traction with atraumatic forceps was used. When necessary, sharp dissection with scissors to remove the adherent part of the cyst from the ovarian parenchyma was performed. Also when necessary, hemostasis with bipolar electro-coagulation was applied with care, aimed at avoiding damage to the normal adjacent ovarian tissue. The cysts were removed using an endobag and a 10-mm trocar. Adhesions or endometriosis in the peritoneum were removed, if present. In the 10 cases of laparotomy, indicated by a large cyst size, a transverse Pfannenstiel incision was performed. Unilateral oophorectomies were performed in four cases because of the macroscopic absence of any 184

3 T. Lind et al. AMH changes following ovarian surgery normal ovarian parenchyma without a cleavage plane. These women were significantly older (median age 39 years, p = 0.01) and all of them had children. All excised specimens were sent for histopathological study. Intraoperative bleeding and duration of surgery, calculated as time from incision to skin closure, were used as surrogate parameters of technical difficulty in dissecting the cysts. The bleeding was assessed by the anesthesiologist at the end of surgery. Serum AMH concentrations were assessed by using a commercial ELISA kit (ACTIVE AMH gen II ELISA; Beckman-Coulter Inc., Webster, TX, USA) at the laboratory of the Department of Clinical Chemistry, Karolinska University Hospital. All blood samples were centrifuged within 4 h and then sent to the laboratory. Serum samples were stored for up to 24 h in a fridge and thereafter in a freezer at 70 C. All stored samples were analyzed sequentially within 1 week. The lowest detectable AMH value of 0.16 lg/l changed to <0.20 lg/l during All values of <0.16 lg/l obtained between 14 March 2011 and 2 March 2012 (n = 13) were changed and recorded as <0.20 lg/l for appropriate comparisons. The intraassay and interassay coefficients of variation were 5.4% and 5.6%, respectively. Antral follicle count was calculated as the total amount of follicles between 2 and 9 mm seen in both ovaries. In 19 of the women who had a cyst enucleation the gynecologists in charge of the presurgery consultation estimated a preoperative AFC. At the 6 months visit, AFC was estimated by a member of the research team (TL). Data analyses Baseline characteristics are presented as absolute and relative frequencies (categorical variables) with either means and standard deviations (SDs) or medians with ranges, as appropriate. Percentage change was calculated as (AMH baseline AMH at 6 months)/amh baseline. One-way analysis of variance test and Pearson s chi-squared test were used to compare subgroups based on histopathology. The Shapiro Wilks test was used to assess normality of distribution of AMH levels. Wilcoxon s signed-rank test was used to test the significance of differences in AMH levels over time. The Mann Whitney U-test and Kruskal Wallis H-test were used to compare AMH values and AMH concentration changes over time, and baseline clinical characteristics between cyst groups according to histopathology. Percentage changes were compared by using the Mann Whitney U-test. Baseline AMH levels were categorized into three groups ( 1.1, 1.2 4, and >4 lg/l) to calculate percentage changes in AMH values over time by category group. Kendall s tau correlation coefficient was used to investigate correlations between AFCs and AMH. In a multivariate regression analysis baseline AMH, age, cyst size, duration of surgery, and assessed bleeding were used as covariates to identify predictors for AMH decrease at 3 and 6 months. All statistical analyses were performed using PASW Statistics 19 software (SPSS Inc., Chicago, IL, USA). Statistical significance was set at a two-tailed p-value of Results Histopathological analyses revealed a cyst of dermoid type in 33 cases, endometriotic type in 25, a simple or functional cyst in nine and cystadenomas (mucinous or serous) in eight. Clinical data of the study cohort including histopathology of the cysts and details of surgery are presented in Table 1. A significantly larger proportion of women with infertility was found in the group of endometriotic cysts. Serum concentrations of AMH were not normally distributed (Shapiro Wilks test) and therefore median values are presented in Figure 1. There was a significant negative correlation between age and preoperative AMH concentration (r = 0.3, p < 0.001). In 67 of 75 women a cyst enucleation was performed. In four cases there was obvious resection of ovarian tissue and in four women unilateral oophorectomy was required. Three women presented with bilateral ovarian cysts, which were enucleated or fenestrated. The amount of intraoperative bleeding (median 50, range ml) and duration of surgery (median 80, range min) were within standard ranges at our clinic. Almost all patients (73/75) had bleeding <200 ml. Only two patients (both with endometriotic cysts) had more bleeding, 500 and 700 ml, respectively. There was a positive correlation between the amount of intraoperative bleeding and duration of surgery (p < 0.001). More abundant intraoperative bleeding also correlated significantly with a greater decrease in AMH levels at 3 months post-surgery (p = 0.020). In the whole group, median AMH levels were significantly reduced when compared with baseline levels both at 3 months (n = 62, p < 0.001) and 6 months postsurgery (n = 67, p < 0.001). There was no further significant reduction in median AMH values from 3 to 6 months. The reduction in AMH levels differed depending on the histopathological diagnosis, i.e. women with endometriomas presented with a more rapid reduction, which was long lasting. They had a 51% reduction in median AMH levels 6 months after surgery (n = 20; p = 0.007), whereas women with dermoid cysts presented with about half of that reduction (25%, n = 31, p = 0.009). Women with cystadenomas or functional cysts (n = 16) had a nonsignificant 34% reduction in AMH levels at 6 months (p = 0.059) (Figure 1). 185

4 AMH changes following ovarian surgery T. Lind et al. Table 1. Clinical characteristics of the women presenting with ovarian cysts. All women (n = 75) Dermoid cysts (n = 33) Endometriomas (n = 25) Functional cysts/ cystadenomas (n = 17) a p-value Age (years) c Body mass index (kg/m 2 ) c Previous pregnancies 0 33 (44) 13 (39) 15 (60) 5 (29) d 1 42 (56) 20 (61) 10 (40) 12 (71) Parity 0 45 (60) 18 (55) 16 (64) 11 (65) d 1 child 30 (40) 15 (45) 9 (36) 6 (35) Infertility 15 (20) 2 (6) 11 (44) 2 (12) d Oral contraceptives Current user 11 (15) 5 (15) 2 (8) 4 (24) d Ex-user 51 (68) 22 (67) 17 (68) 13 (76) d Smoking status Current smoker 13 (17) 5 (15) 2 (8) 6 (36) d Surgery Previous 14 (19) 4 (12) 3 (12) 7 (41) d gynecological surgery Previous ovarian cyst surgery 6 (8) 2 (6) 1 (4) 3 (18) b d Cyst size (cm) (2.0 15) (2.5 12) (2.0 10) (2.0 15) c mean SD (range) Laparoscopy 65 (87) 28 (85) 22 (88) 15 (88) d Laparotomy 10 (13) 5 (15) 3 (12) 2 (12) Bleeding (ml) mean SD (range) (0 700) (0 150) (0 700) (0 200) c Duration of surgery (min) (31 173) (30 173) (33 160) (40 115) c mean SD (range) Type of surgery Oophorectomy 4 (5) 2 (6) 0 2 (12) d Resection of the ovary 4 (5) 1 (3) 2 (8) 1 (6) Cyst enucleation 65 (87) 30 (91) 21 (84) 14 (82) Bilateral cyst enucleation/fenestration 2 (3) 0 2 (8) 0 Data are presented as mean SD or n (%). a Functional cysts: follicle cysts or simple functional cyst, normal findings in histopathology. b One patient had undergone cyst surgery twice. c One-way analysis of variance test. d Pearson s chi-squared test. A subgroup analysis by cyst histopathology including only the 54 women who underwent a unilateral cyst enucleation, confirmed that median serum AMH levels were significantly lower in women with endometriomas than in women with dermoid cysts at 3 months (n = 51, p = 0.010) and 6 months postoperatively (n = 54, p = 0.008) (Figure 2). The groups were similar at baseline as regards clinical characteristics and did not differ significantly in age, body mass index, parity, or cyst size. None of the women of this subgroup analysis had had previous ovarian surgery. Although the duration of surgery did not differ significantly between the groups, blood loss was significantly more abundant in surgery of endometriotic cysts (p = 0.014). Women who had AMH concentrations in the lowest category ( 1.1 lg/l) before cyst surgery, presented with no median percentage change from baseline to 6 months (Figure 3). The two remaining groups, with normal or elevated AMH levels at baseline, presented with median decreases of 23% and 43%. These changes differed significantly between the low AMH and both the normal and high AMH category groups (p = 0.010). A similar analysis including only the 54 women who underwent a cyst enucleation confirmed these results. A small proportion of about one-fifth of the patients in each group [five women with dermoid cysts (17%), four with endometriotic cysts (19%) and two with functional/cystadenomas cysts ([17%)] showed an increase in serum AMH levels 6 months postoperatively vs. baseline levels. Comparison of the women who showed an AMH increase and the women who showed an AMH reduction following cyst surgery did not reveal any significant 186

5 T. Lind et al. AMH changes following ovarian surgery Figure 1. Median anti-m ullerian hormone (AMH) concentrations by cyst histopathology groups at baseline (pre-surgery) and at 3- and 6-months post-operative in women who had all three AMH timepoint measurements (n = 54). Difference within groups derived by Wilcoxon signed rank test and between groups by Mann Whitney U-test. *p < 0.05 for the differences within groups from baseline AMH to 3 and 6 months. **p < 0.03 for the differences within groups from baseline AMH to 3 and 6 months. ***p < 0.03 for the differences between dermoid cyst and endometrioma groups at 3 and 6 months. Note that no statistically significant differences were found when comparing functional cyst/cystadenoma vs. dermoid cyst or vs. endometrioma groups. differences as regards age, body mass index, cyst type or size, time of surgery or intraoperative blood loss. However, eight of 11 women who had an increase of AMH presented with baseline levels in the lowest category group, 1.1 lg/l. In the multivariate regression analysis of the women who underwent a cyst enucleation, a higher serum AMH concentration at baseline was the only predictive variable for a reduction in AMH postoperatively at 3 and 6 months [odds ratio (OR) 1.9, 95% CI and OR 2.5, 95% CI , respectively]. Patient s age, cyst size, duration of surgery, or intraoperative bleeding were not as predictive of a postoperative AMH decrease. Antral follicle counts showed a wide range in the 19 women with a cyst enucleation who were investigated at the presurgery visit (median 11 follicles, range 1 16) and at 6 months of follow up (median 14 follicles, range 2 23). There was a significant correlation between serum AMH levels and AFCs, both at baseline (p = 0.009) and at 6 months postoperatively (p = 0.005). Figure 2. Median anti-m ullerian hormone (AMH) concentration at baseline (blue) and 6-months (green) by cyst histopathology in the sub-group of women who had a unilateral cyst and underwent a clean cyst enucleation (n = 54). Please note that the groups are not identical to the ones in Figure 1. The groups were similar at baseline as regards clinical characteristics and did not differ significantly in age, body mass index, parity, cyst size. None of the women of this subgroup analysis had had previous ovarian surgery. Difference within groups derived by Wilcoxon signed rank test and between groups by Mann Whitney U-test. *p < 0.05 for the differences within groups from baseline AMH to 3 and 6 months. **p < 0.03 for the differences within groups from baseline AMH to 3 and 6 months. ***p < 0.03 for the differences between dermoid cyst and endometrioma groups at 6 months. Note that no statistically significant differences were found when comparing functional cyst/ cystadenoma vs. dermoid cyst or vs. endometrioma groups. Discussion Our results showed that the AMH decrease differed significantly between women with endometriomas and women with dermoid cysts. Women with endometriomas showed a more rapid and sustained decline in AMH levels. The postoperative decline in AMH was greater at 3 months in women who had more abundant intraoperative bleeding in our study, suggesting that even by the most conservative techniques for cyst enucleation, an effect on ovarian reserve estimated by AMH may still occur. At least part of that effect might be associated with technical difficulties of dissecting cysts that are more adherent (10,17). However, AMH is not inevitably reduced after ovarian cyst surgery in all women. Our results also indicate that in some cases, the cyst itself might have had a negative impact on ovarian physiology, as indicated by the increase in serum AMH levels postoperatively in some patients. 187

6 AMH changes following ovarian surgery T. Lind et al. Figure 3. Median anti-m ullerian hormone (AMH) concentrations by category groups depending on baseline AMH concentrations (blue) and their changes after ovarian surgery at 3- (green) and 6-months (brown). Difference within groups derived by Wilcoxon signed rank test and between groups by Mann Whitney U-test. *p < 0.05 for the difference within groups from baseline AMH to 3 and 6 months. **p < 0.03 for the difference within groups from baseline AMH to 3 and 6 months. ***p < 0.03 for the differences between low AMH group and both the normal and high AMH group. Note that no statistically significant differences were found when comparing normal and high AMH groups. Strengths of our study are the relatively large number of patients included, with a variety of types of cyst, in comparison with previous reports, which gives our study results greater external validity, and the prospective design with a relatively long follow-up period of 6 months (11,12,14). In fresh serum, AMH concentrations appear to increase progressively at room temperature with the ACTIVE AMH gen II ELISA kit (Beckman-Coulter) (18). All AMH estimates in our study were analyzed in frozen samples at the same laboratory and the median time before analysis was 6 days, which minimizes the risk of false values (19). Regarding limitations, although we found great variation in AFCs, the increase in AFC at the 6-month post-surgery visit in the 19 women investigated is also an interesting finding. Possible prevention of a correct count before surgery because of the presence of a cyst has to be considered, or, as suggested by others, a reactive response of ovarian parenchyma after surgery (13). That different physicians were involved in the estimation of AFC at baseline may also have introduced further variability in the counts. The negative impact of ovarian cyst surgery on ovarian reserve has been previously reported, in particular as regards women with endometriomas (9,12,13,20). The small sample size and shorter follow up of these studies have not allowed dermoid cysts to be studied as a homogeneous group (10 12,14). This prospective investigation of changes in serum AMH concentrations following conservative ovarian surgery in women presenting with various histopathological types of cysts and including a large number of patients with endometriomas, follicular/ mucinous cysts and dermoid cysts made it possible to compare those groups as such. The slower and smaller decrease in AMH concentrations in women who underwent enucleation of dermoid cysts (27% reduction from baseline levels at 6 months) vs. endometriomas (36%) might be partially explained by difficulties in cyst dissection and the damaging effect of electrocoagulation on blood supply to the ovary, as the cleavage plane is more difficult to identify and the surgical technique is more arduous for enucleation of endometriomas vs. dermoid cysts (21). Additionally, the risk of removing healthy ovarian tissue is higher when removing endometriotic cysts than when removing dermoid or other cysts, owing to the fact that endometriomas are pseudocysts with invagination of the ovarian cortex (22). Several studies have revealed that healthy ovarian tissue is often removed during surgery of endometriotic cysts (up to 54%) and the incidence is reduced in cases of dermoid cysts (17%) or is negligible (0%) in serous and mucinous cysts (23,24). In our study, women with follicular cysts or cystadenomas showed only discrete changes in AMH concentrations at 3 months, which had returned to baseline levels at 6 months. We believe that the significant decline of AMH seen at 6 months in women with dermoid cysts in our study indicates that dermoid cysts may also have areas where the capsule is more adherent to the ovarian stroma and therefore their dissection might be more difficult and bleeding more profuse, which could explain the significant reduction in AMH levels found in that group. An interesting finding in our study was that AMH levels did not always decrease after cyst surgery, as a fifth of the women showed an increase in AMH levels at 6 months. It is possible that patients whose cysts were less adherent could maintain healthy ovarian tissue. Some recent studies (25) have shown that AMH levels may change during the menstrual cycle in women presenting with AMH levels in the higher quartiles, which could partially explain the greater changes in AMH levels over time in the women with higher preoperative AMH levels in this study. However, it is also plausible that as they have more follicles in their ovaries there was also a higher risk of involuntarily removing a larger 188

7 T. Lind et al. AMH changes following ovarian surgery number of follicles during surgery, which could explain the rapid reduction in AMH concentrations. Additionally, recent data suggest that postoperative changes in AMH levels may occur subsequent to rearrangement of the follicle cohort, depending on the amount of follicles removed during surgery (26). In our cohort, women presenting with normal and high baseline AMH concentrations showed the greatest reduction in AMH levels after surgery, indicating that the ovaries of women with high ovarian reserve and those with polycystic ovaries (AMH levels >4 lg/l) (27) are also very sensitive to conservative ovarian interventions. Our finding of a significant but smaller reduction in AMH concentrations following surgery in women with already low AMH levels before intervention and an already much reduced cohort of growing follicles, may also indicate that changes in AMH levels in those patients might have a lower clinical predictive value than equivalent changes in women with a normal or high ovarian reserve. We know that patients with reduced ovarian reserve may still become pregnant, even spontaneously, but that their chance of conceiving is much lower than that of women with serum AMH levels within normal reference levels (28). It would have been interesting to evaluate the follicle density in the ovarian tissue removed. However, resection of ovarian tissue occurred only in eight cases and identification of ovarian cortical tissue only in a few of those. Due to ethical considerations, we did not plan to perform a biopsy of macroscopically normal ovarian tissue in this study. Our results are applicable to women of reproductive age undergoing cyst enucleation and indicate that conservative surgery of benign ovarian cysts may be deleterious to ovarian reserve, in particular as regards women with endometriomas and those in whom there is a more difficult surgical dissection and more abundant intraoperative bleeding. Although some authors have advocated restriction of ovarian cyst surgery (29), surgical intervention in our study cohort was needed as a result of the clinical signs and symptoms. More importantly, five women out of the 112 recruited in our study presented with cysts that were discovered to be malignant at the time of surgery. Additionally, endometriosis and the presence of ovarian endometriomas are associated with a threefold increased risk of ovarian cancer (30). The women in our study were not seeking fertility treatment at the time the cysts were discovered and operated. We might recommend infertile women with reduced ovarian reserve who present with asymptomatic cysts of small size and benign aspect to undergo their infertility treatment before ovarian cyst surgery. Most of the women in our study presenting with low ovarian reserve at baseline did not have normalized values after follow up. Conclusion Our study shows a reduction of AMH levels after ovarian surgery, especially among women with endometriomas and in women with normal and high baseline AMH concentrations. Adequate counseling regarding the possible effects of ovarian surgery on ovarian reserve should take place before deciding on ovarian surgery in women of fertile age, in particular if the women have a wish for future children. Longer follow-up studies are needed to investigate if there is an effect of ovarian surgery on fertility with regard to pregnancy and birth rates. Funding This work was supported by grants from the local Research, Education and Development council, the Department of Obstetrics and Gynecology, S odersjukhuset and the Department of Clinical Science, Intervention and Technology, Karolinska Institutet. KRW is a recipient of Swedish Research Council and Stockholm County Council research grants. Acknowledgments The authors thank Lina Benson for expert statistical advice, Gunilla H ojer and Annika Mauritzon-Golitats for assistance with patient recruitment and administrative help during the study, and the gynecological surgery staff at S odersjukhuset. References 1. Almog B, Shehata F, Sheizaf B, Tulandi T. Effect of different types of ovarian cyst on antral follicle count. Fertil Steril. 2010;94: Borgfeldt C, Andolf E. Transvaginal sonographic ovarian findings in a random sample of women years old. Ultrasound Obstet Gynecol. 1999;13: Statistikdatabasen, Operationer i slutenvard. (Operations in inpatient care). [Internet] Available online at: (accessed September 15, 2014). 4. RCOG. Management of suspected ovarian masses in premenopausal women. 2011; Green-top Guideline, No. 62. London: RCOG, La Marca A, Sighinolfi G, Radi D, Argento C, Baraldi E, Artenisio AC, et al. Anti-Mullerian hormone (AMH) as a predictive marker in assisted reproductive technology (ART). Hum Reprod Update. 2010;16: Nelson SM, Anderson RA, Broekmans FJ, Raine-Fenning N, Fleming R, La Marca A. Anti-Mullerian hormone: clairvoyance or crystal clear? Hum Reprod. 2012;27:

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