Surgical diminished ovarian reserve after endometrioma cystectomy versus idiopathic DOR: comparison of in vitro fertilization outcome.

STUDY QUESTION: Does the live birth rate after IVF depend on the etiology of diminished ovarian reserve (DOR)? SUMMARY ANSWER: IVF outcome and live birth rate are significantly impaired in women with DOR caused by a previous cystectomy for endometrioma compared with women with idiopathic DOR. WHAT IS KNOWN ALREADY: The safety of the surgical treatment of endometriomas is being discussed in terms of damage to ovarian reserve. Several studies have reported a poor response to controlled ovarian stimulation and a significantly impaired IVF outcome in women with DOR consecutive to an endometrioma cystectomy compared with women with tubal factor infertility. STUDY DESIGN, SIZE, DURATION: Retrospective case-control study conducted in women aged under 40 treated in our Reproductive Medicine Center between January 2010 and January 2014 for a DOR defined by anti-Müllerian hormone level <2 ng/ml. Two groups of patients were selected: group A included patients with a DOR diagnosed after cystectomy(s) for endometrioma(s), group B included patients with an idiopathic DOR. In each group, subgroups of patients 'poor ovarian responders', based on the ESHRE criteria ('Bologna criteria'), have been established. PARTICIPANTS/MATERIALS, SETTING, METHODS: A total of 51 patients in group A were matched to 116 patients in group B, representing respectively 125 and 243 IVF cycles. Among them, 39 patients in group A and 78 patients in group B validated strictly by the Bologna criteria, representing 99 and 189 IVF cycles, respectively. Each patient underwent a controlled ovarian hyperstimulation and IVF with fresh embryo transfer. Primary end-point was the live birth rate. Secondary end-points were the number of retrieved oocytes, fertilization rate, implantation rate, clinical pregnancy rate, spontaneous abortion rate and cycle cancelation rate. MAIN RESULTS AND THE ROLE OF CHANCE: Significantly lower pregnancy (11.2% in group A versus 20.6% in group B, P = 0.02) and live birth (7.2 versus 16.9% respectively, P = 0.01) rates per cycle were assessed in women in group A compared with women in group B. The same results were obtained in the Bologna criteria subgroup analysis with a significantly lower pregnancy (9.1 versus 20.1%, P = 0.016) and live birth (5.1 versus 15.3%, P = 0.001) rates per cycle in women in subgroup A compared with women in subgroup B. Patients in group A required significantly higher gonadotrophins doses (2881 IU ± 1111 versus 2526 IU ± 795, P = 0.005), longer ovarian stimulation (10.6 Days ± 2.8 versus 9.9 Days ± 2.4, P = 0.019) and higher cancelation rate for poor response (12 versus 6.2%, P = 0.05). Despite a mean number of retrieved oocytes similar with the group B (5.4 ± 3.1 and 5.1 ± 3.2, NS), and a significantly higher fertilization rate (65.7 versus 47.2%, P < 0.001), women in group A showed a significantly lower implantation rate (7.2 versus 13.5%, P = 0.03). Abortion rate, ectopic pregnancy rate and multiple pregnancy rate were similar in both groups. LIMITATIONS, REASONS FOR CAUTION: Data were collected retrospectively using the database of our Department. Sample size is relatively small but our study provides statistically significant evidence that the chances of IVF success are decreased in women with DOR after cystectomy for endometrioma. Further larger series are needed to confirm these findings. WIDER IMPLICATIONS OF THE FINDINGS: To our knowledge, this is the first study evaluating IVF outcome in patients with DOR after cystectomy(s) for endometrioma(s) versus in patients with an idiopathic DOR. In addition to the risk of damaging ovarian reserve, we hypothesize that endometrioma surgery would not have qualitative benefits on results in IVF in patients with DOR. STUDY FUNDING/COMPETING INTERESTS: The authors have no competing interests to declare.

Evaluating methods of mouse euthanasia on the oocyte quality: cervical dislocation versus isoflurane inhalation.

Cervical dislocation is a commonly used method of mouse euthanasia. Euthanasia by isoflurane inhalation is an alternative method which allows the sacrifice of several mice at the same time with an anaesthesia, in the aim to decrease pain and animal distress. The objective of our study was to assess the impact of these two methods of euthanasia on the quality of mouse oocytes. By administering gonadotropins, we induced a superovulation in CD1 female mice. Mice were randomly assigned to euthanasia with cervical dislocation and isoflurane inhalation. Oviducts were collected and excised to retrieve metaphase II oocytes. After microscopic examination, oocytes were classified into three groups: intact, fragmented/cleaved and atretic. Intact metaphase II oocytes were employed for biomedical research. A total of 1442 oocytes in the cervical dislocation group were compared with 1230 oocytes in the isoflurane group. In the cervical dislocation group, 93.1% of the oocytes were intact, versus 65.8% in the isoflurane group (P ≤ 0.001). In light of these results, we conclude that cervical dislocation is the best method of mouse euthanasia for obtaining intact oocytes for biomedical research.