Effects of Ovarian Surgery on Ovarian Reserve and Fertility

The objective of this thesis was to investigate shortand long-term effects of ovarian surgery on the ovarian reserve of women of reproductive age. This research also considered their reproductive outcomes with regard to conceiving spontaneously or using assisted reproductive techniques (ART). We also wished to explore how women perceived the information they received about fertility when planning for ovarian surgery. In paper I, a cross-sectional study that included 106 women, we investigated patients’ perceptions of the fertility-related information they received as well as fertility distress prior to ovarian cyst surgery. Although a high proportion of the women (72 %) desired to have children in the future, only half recalled receiving information about the potential impact of surgery on fertility. In a multivariable logistic regression, desire for children was the only association with recalled fertility-related information. Additionally, more than half of the women (54 %) reported fertility distress with VAS-scores ≥ 5 prior to surgery. Paper II involves a prospective clinical cohort study that included 75 women planned for conservative ovarian cyst surgery (cystectomy, ovarian resection or unilateral oophorectomy). We investigated the effects of removed cysts’ histopathology on women’s ovarian reserve, estimated as serum concentrations of Anti-Mullerian Hormone, AMH. The AMH levels declined significantly from presurgery levels of 2.7 μg/L (0.2-16.9) to 1.6 μg/L (0.2-9.9) at three months, and the levels remained low at six months, 1.6 μg/L (0.2-8.3) (p<0.001, respectively). In patients who had a single cyst enucleation, a reduction was observed after surgery for both endometriomas and dermoid cysts. In a logistic regression, the only predictive factor found for the decline of AMH serum concentrations was a higher baseline AMH level prior to surgery. In paper III, we prospectively investigated the changes in AMH after a long-term postoperative follow-up of two years in 66 of the women included in the clinical cohort study. The progressive post-operative decline of serum AMH concentrations continued over time. The AMH serum concentration significantly reduced from 2.7 μg/L at baseline to 2.0 μg/L at six months. We observed a further reduction to 1.0 μg/L at the two-year follow-up (p = 0.001, respectively). Nonetheless, women who attempted pregnancy succeeded in 58 % of the cases. Women with normal or high AMH at baseline had a higher chance of conceiving, regardless of their AMH reduction over time. In paper IV, we examined the clinical pregnancy rate after Assisted Reproductive Technology (ART) in a cohort of 76 women with a history of unilateral oophorectomy (UO), as compared to 12879 controls. Exposed women with UO and unexposed controls were included at three ART Swedish clinics. In this multicentre study, single embryo transfer was performed in 77 % of cases; analysis showed a significant reduction of 30 % in the clinical pregnancy rate of women with UO compared to controls, both crude and after adjustment for age. Conclusion: The studies included in this thesis indicate that the ovarian reserve, estimated by its biochemical marker AMH, decreases significantly after conservative ovarian surgery for cysts in women of fertile age. The post-operative AMH decrease continues two years following the ovarian surgery, even though no macroscopic ovarian tissue was reported as being removed at the time of surgery. The reduction in AMH does not seem to affect fertility in women presenting with normal or high AMH serum concentrations prior to ovarian surgery. On the other hand, women of fertile age who had a previous surgical removal of one ovary had reduced chances of pregnancy, estimated as reduced clinical pregnancy rate after ART. Women require this important information in order to make decisions regarding their reproductive ability; however, our research evidenced that women were not properly informed of the potentially negative effects of ovarian surgery on reproduction. LIST OF SCIENTIFIC PAPERS I. Lind, T, Lampic C, Hammarström M, Rodriguez-Wallberg K. “Young women's perceptions of fertility-related information and fertility distress before surgery for ovarian cysts.” Acta Obstet Gynecol Scand. 2013: 92(11): 1290-1296. II. Lind T, Hammarström M, Lampic C, Rodriguez-Wallberg K. “AntiMüllerian hormone reduction after ovarian cyst surgery is dependent on the histological cyst type and preoperative anti-Müllerian hormone levels.” Acta Obstet Gynecol Scand. 2015: 94; 183-190. III. Lind T, Hammarström M, Lampic C, Olofsson JI, Rodriguez-Wallberg K. “AMH reduction following ovarian cyst surgery does not reduce fecundity in women with normal/high AMH.” Submitted. IV. Lind T, Holte J, Olofsson JI, Hadziosmanovic J, Berglund L, Gudmundsson J, Rodriguez-Wallberg K. “Reduced pregnancy rates after IVF/ICSI in women with a history of unilateral oophorectomy. Results of a multi-centre cohort study.” Submitted. CONTENTS 1 Introduction ..................................................................................................................... 7 2 Background ..................................................................................................................... 8 2.1 Fertility .................................................................................................................. 8 2.2 Oocyte development ............................................................................................. 8 2.2.1 Development of a mature oocyte to achieve ovulation ........................... 9 2.2.2 Menstrual cycle ...................................................................................... 10 2.3 Ovarian reserve ................................................................................................... 11 2.4 Assessments of ovarian reserve .......................................................................... 12 2.4.1 Menstrual cycle length ........................................................................... 12 2.4.2 Follicle-Stimulating Hormone (FSH) .................................................... 12 2.4.3 Anti-Müllerian Hormone (AMH) .......................................................... 13 2.4.4 Measurement of AMH ........................................................................... 15 2.4.5 Antral follicle counts (AFC) .................................................................. 16 2.5 Assisted reproductive technique (ART) ............................................................. 17 2.6 Ovarian cysts ...................................................................................................... 18 2.6.1 Impacts of ovarian cyst surgery on ovarian reserve .............................. 19 2.6.2 Patients’ fertility-related information prior to ovarian surgery ............. 22 2.6.3 Effects of unilateral oophorectomy ....................................................... 22 2.7 Aspects of infertility in women .......................................................................... 25 3 Rationale ....................................................................................................................... 27 4 Aims .............................................................................................................................. 28 5 Methods ......................................................................................................................... 29 5.1 Study design ........................................................................................................ 29 5.2 Study subjects ..................................................................................................... 30 5.2.1 Study I (Papers IIII) ............................................................................. 30 5.2.2 Study II (paper IV) ................................................................................. 31 5.3 Exposure ............................................................................................................. 32 5.3.1 Ovarian cyst surgery (papers II and III) ................................................ 32 5.3.2 Unilateral oophorectomy study II (paper IV) ........................................ 33 5.4 Evaluated parameters .......................................................................................... 33 5.4.1 Questionnaire study I (paper I) .............................................................. 33 5.4.2 Questionnaire (paper III) ....................................................................... 34 5.4.3 AMH measurement (papers II-III) ........................................................ 34 5.4.4 Antral follicle count (AFC) (paper II) ................................................... 34 5.4.5 ART treatment study II (paper IV) ........................................................ 35 5.4.6 Reproductive outcome ........................................................................... 36 5.4.7 Ovarian sensitivity index ....................................................................... 36 5.5 Statistics .............................................................................................................. 36 5.5.1 Paper I .................................................................................................... 36 5.5.2 Papers II and III ..................................................................................... 36 5.5.3 Paper II ................................................................................................... 37 5.5.4 Paper III .................................................................................................. 37 5.5.5 Paper IV ................................................................................................. 37 6 Ethical considerations ................................................................................................... 38 7 Results ........................................................................................................................... 38 7.1.1 Paper I .................................................................................................... 39 7.1.2 Paper II ................................................................................................... 39 7.1.3 Paper III .................................................................................................. 41 7.1.4 New subgroup analyses for this thesis ................................................... 41 7.1.5 Paper IV ................................................................................................. 43 8 Discussion ..................................................................................................................... 45 8.1.1 AMH changes following ovarian surgery ............................................. 45 8.1.2 AMH changes dependent on histopathology type of cysts ................... 46 8.1.3 Predictors for AMH changes following ovarian surgery ...................... 47 8.1.4 AMH changes following ovarian surgery and pregnancy rates ............ 48 8.1.5 Pregnancy rates and histopathology of the cyst .................................... 48 8.1.6 Clinical pregnancy rate following ART in women with UO ................ 49 8.1.7 Fertility-related information prior to ovarian surgery ........................... 50 8.1.8 Ovarian surgery in Sweden and ovarian reserve screening .................. 50 8.2 Methodological considerations ........................................................................... 51 8.2.1 Study design and validity ....................................................................... 51 9 Conclusion ..................................................................................................................... 54 9.1 Clinical implications ........................................................................................... 54 9.2 Future research .................................................................................................... 55 10 Sammanfattning på svenska ........................................................................................ 56 11 Acknowledgements ...................................................................................................... 58 12 References .................................................................................................................... 60 LIST OF ABBREVIATIONS AFC Antral Follicle Counts AMH Anti-Müllerian Hormone