In vitro fertilization outcome in women with endometriosis & previous ovarian surgery.

Patients characteristics and ovarian stimulation parameters are shown in Table I . Women with endometriosis required more ampoules of gonadotropins and attained lower serum E2 levels on day 7. The number of follicles ≥16mm on the day of hCG administration was significally ( P <0.05) lower compared to tubal factor patients group. Primary infertility and OHSS rates were significally ( P <0.05) lower in women in the endometriosis group. Patient characteristics and controlled ovarian hyperstimulation parameters IVF laboratory parameters are presented in Table II . Cycle cancellation rate was significally ( P <0.01) higher for women in the endometriosis group compared with contro group. Also, the total number of oocytes retrieved and total numer of embryos were significally lower in these endometriosis group. No significant differences were found between the groups with regard to the fertilization rate or percentage of blastocysts. A similar number of embryos were transfered in both the groups. IVF laboratory parameters in women with endometriosis compared with women with tubal factor infertility Implantation rates, clinical pregnancy rates and live birth rates were comparable between the two groups. No significant differences were found in the miscarriage rate and multifoetal pregnancy rate between the endometriosis and tubal factors infertility groups of patients ( Table III ). IVF outcomes (%) in women with endometriosis and tubal factor infertility

A total of 235 first-attempt IVF cycles performed in two IVF units outcome (IVF unit in clinic for Gynaecology and Obstetrics Clinical Center of Nis, Serbia and IVF unit in clinic for gynecology and obstetrics, Clinical Center of Vojvodina Novisad, Serbia) were prospectively analyzed in three years period (December 2009-December 2012). The study protocol was approved by the Ethics Commitee of both IVF units and the study was conducted after obtaining informed written consent of all patients. A total of 78 women were enrolled consecutively and diagnosed with endometriosis. All patients with endometriosis have previosly undergone laparoscopy; 40 patients were diagnosed with minimal and mild endometriosis (American Society for Reproductive Medicine stage I/II) and 38 with moderate and severe endometriosis (American Society for Reproductive Medicine stage III/IV) 8 . Of these 78 women, 68 had undergone only one and 12 more than one surgical procedures. In all patients with ovarian endometriosis the “stripping” technique was used to excide endometriomas and the diagnosis was histologically confirmed. All patients with endometriosis were treated with 3-6 cycles of gonadotropin releasing hormone (GnRH) analogues after laparoscopy and prior to IVF. The control group consisted of 157 women who underwent IVF treatment during the same time period, with laparoscopically diagnosed tubal factor infertility and without any evidence of endometriosis. Sample size estimation was performed to determine the number of women per group sufficient to detect a true odds ratio (OR) of 2.5. With a power of 80 per cent, type 1 error of 5 per cent, and 0.20 probability of exposure in controls, it was calculated that at least 69 subjects (ORs = 2.5) were required in the study group and at least 138 subject in the control group. Depending on the women's age, the antral folicle count and the basal (day 3) follicle stimulating hormone (FSH), the long GnRH-agonist downregulation protocol (Dipherelin 0,1 mg, Ipsen Pharma Biotech, France), the short GnRH-agonist or GnRH antagonist protocol (Cetrotide, Serono Pharma, Switzerland) were used. Ovulation stimulations were conducted with daily subcutaneous injections of individual starting doses of rFSH (Folitropin alpha- Gonal F, Serono Pharma, Switzerland or Folitropin beta- Puregon, Organon, or human menopausal gonadotropin (hMG) (Menopur, Feriing, Germany) at appropriate doses (50-450IU). Ovarian response to gonadotropins was monitored by transvaginal ultrasound and serum estradiol (E2) measurement (Abcam, USA) every second day from day 7. Ovulation was triggered by injecting 10000IU hCG when the leading follicle reached 18 mm with appropriate serum E2 levels. Thirty six hours after administration of human chorionic gonadotropin (hCG), transvaginal ultrasound-guided oocyte aspiration was performed under local anaesthesia. After cultivation, embryo transfer was performed 3 to 5 days after oocytes aspiration. All patients received luteal phase support for two weeks. Clinical pregnancy was defined as the visualization of gestational sac at ultrasound examination and biochemical pregnancy was defined as detection of β-hCG levels in serum but no signs of pregnancy by ultrasound. Data are expressed as the mean ± standard deviation or as percentages. Statistical comparisons among groups were performed using the Fisher exact test, χ2 test, Wilcoxon's test or Student's t test as appropriate.

There is a lack of consensus among studies as to whether ovarian response is adequate or suboptimal in patients with ovarian endometriosis. Some studies have reported impaired ovarian responsiveness to ovarian stimulation in patients with endometriosis 8 9 and others reported lack of adverse effect 10 11 . We found a detrimental relationship between endometriosis and ovarian response during controlled ovarian hyperstimulation in IVF. Despite having similar FSH levels on day 3 in women with endometriosis with previous ovarian surgery compared with those with tubal factor infertility, women with endometriosis required significantly higher dosages of gonadotropins, achieved lower peak E2 levels and yielded fewer oocytes. Women with endometriosis had also higher cycle cancellation rates. These findings suggested that the ovarian responsiveness was damaged after the presence and excision of ovarian endometriomas. There are currently insufficient data to clarify whether this endometrioma-related damage to ovarian responsiveness precedes or follows surgery. Elucidation of this point is important as it would impact on the decision of whether to operate on women with endometriosis who are selected for IVF. At present, there appears to be evidence supporting both an endometrioma-related injury 12 13 and surgery-mediated damage 14 15 . There is also a lack of consensus in the reported literature on IVF success in patients with endometriosis. In a meta-analysis of 22 studies, Barnhart et al 16 reported that the odds of pregnancy in patients with endometriosis undergoing IVF/ET was 50 per cent compared to women with tubal factor infertility. The findings of Witsenburg et al 17 are in contrast to the previous one. Based on the Centers for Disease Control (CDC) data, similar pregnancy and live birth rates have been reported when comparing couples with diagnosis of tubal factor infertility, ovulatory disfunction, endometriosis, male factor and unexplained infertility 17 . We found no adverse outcome of endometriosis (after ovarian surgery) on fertilization and implantation rate in the present study. Although fewer embryos were available for tranfer, as a consequence of fewer yielded oocytes, the same number of embryos were transfered. Moreover, in contrast to other groups of women with diminshed ovarian reserve, implantation rate, pregnancy rates and misccariage rates were similar in the two groups. There were no significant differences in the live birth rates between women with endometriosis and those with tubal factor infertility. These contrasting results can be explain by several hypotheses. First of all, it seems that reduced ovarian responsiveness is related to quantitative rather than quantitative damage after surgery for ovarian endometriosis. Secondly, ovarian endometriomas are monolateral in 72-81 per cent of cases 18 . Bilateral disease was present in 13 per cent of patients in our study. The contralateral intact ovary may adequately compensate for the reduced function of the affected one. Third, all patients in our study were treated with GnRH agonists for 3 to 6 month after the surgery and prior to IVF. Data from Cohrane collaboration reports that long-term administration of GnRH agonists prior to IVF in women with endometriosis increases the odds of clinical pregnancies by at least four-fold and live-birth rate by tree-fold 19 . The improvement in the live birth and clinical pregnancy rate in patients receiving GnRH analogues may be due to an improvement in the quality of oocytes (and hence the embryos) or due to an improvement in the uterine receptivity leading to better implantation and diminshed loss of very early pregnancies. Many studies have tried to give an answer by using oocyte donation (OD) programme 20 21 22 . The overall conclusion, using the fact that women receiving oocytes from donors with endometriosis had reduced implantation rate and on the other hand, the women patients with and without endometriosis receiving oocyte from non endometriotic donor had the same implanatation rate, was that endometrial priming protocol with GnRH agonists used in OD cycles reestablished an adequate uterine cavity environment. One of the prosposed mechanisms is that GnRH agonists restore the normal apoptotic rate (usually low in eutopic and ectopic endometrial cells from women with endometriosis) 23 . There is a need for further research into the exact mechanism by which GnRH agonist improves pregnancy rates. Inspite the fact that women with endometriosis require higher doses of gonadotropins for ovarian stimulation and hence the cost of treatment to achieve pregnancy is higher, the outcome of IVF treatment in women with endometriosis is as good as in women with tubal factor infertility.