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To study the effect of increasing endometrial thickness on live birth rates in fresh and frozen-thaw embryo transfer (FET) cycles.Retrospective cohort study.National data from Autologous in vitro fertilization (IVF) embryo transfer and FET cycles in Canada from the Canadian Assisted Reproductive Technology Registry Plus (CARTR Plus) database for records between January 2013 and December 2019.Thirty-three Canadians clinics participated in voluntary reporting of IVF and pregnancy outcomes to the Canadian Assisted Reproductive Technology Registry Plus database, and a total of 43,383 fresh and 53,377 frozen transfers were included.None.Clinical pregnancy, pregnancy loss, and live birth rates.In fresh IVF-embryo transfer cycles, increasing endometrial thickness is associated with significant increases in the mean number of oocytes retrieved, peak estradiol levels, number of usable embryos, clinical pregnancy rates, live birth rates, and mean term singleton birth weights, and a decrease in pregnancy loss rates. However, live birth rates plateau after 10-12 mm. In contrast, in FET cycles live birth rates plateau after the endometrium measures 7-10 mm. The improvement in live birth rates with increasing endometrial thickness was independent of patient age, timing of embryo transfer (e.g., cleavage stage vs. blastocyst stage), or the number of oocytes at retrieval.In cycles with a fresh embryo transfer, live birth rates increase significantly until an endometrial thickness of 10-12 mm, while in FET cycles live birth rates plateau after 7-10 mm. However, an endometrial thickness6 mm was associated clearly with a dramatic reduction in live birth rates in fresh and frozen embryo transfer cycles.

Objective To provide a comprehensive review and evidence-based recommendations for the delivery of fertility care to women with obesity. Outcomes The impact of obesity on fertility, fertility treatments, and both short and long-term maternal fetal outcomes was carefully considered. Evidence Published literature was reviewed through searches of MEDLINE and CINAHL using appropriate vocabulary and key words. Results included systematic reviews, clinical trials, observational studies, clinical practice guidelines, and expert opinions. Values The Canadian Fertility & Andrology Society (CFAS) is a multidisciplinary, national non-profit society that serves as the voice of reproductive specialists, scientists, and allied health professionals working in the field of assisted reproduction in Canada. The evidence obtained for this guideline was reviewed and evaluated by the Clinical Practice Guideline (CPG) Committee of the CFAS under the leadership of the principal authors. Benefits, Harms, and Costs The implementation of these recommendations should assist clinicians and other health care providers in counselling and providing reproductive care to women with obesity. Validation This guideline and its recommendations have been reviewed and approved by the membership, the CPG Committee and the Board of Directors of the CFAS. Sponsors Canadian Fertility & Andrology Society. Recommendations Twenty-one evidence based recommendations are provided. These recommendations specifically evaluate the impact of obesity on natural fertility, fertility treatments, and maternal-fetal outcomes. Strategies to lose weight and BMI cut-offs are also addressed.

Objective To provide a comprehensive review and evidence based recommendations for Canadian fertility centres that offer social egg freezing. Outcomes In social egg freezing cycles we evaluated thawed oocyte survival rates, fertilization rates, embryo quality, pregnancy rates, and live birth rates. We also review how these outcomes are impacted by age, ovarian reserve, and the number of eggs cryopreserved. Finally, we discuss the risks of social egg freezing, the alternatives, the critical elements for counselling and informed consent, and future reporting of egg freezing outcome data. Evidence Published literature was reviewed through searches of MEDLINE and CINAHL using appropriate vocabulary and using key words ("oocyte cryopreservation," "egg freezing," "egg vitrification," "social egg freezing," and "elective egg freezing"). Results included systematic reviews, randomized controlled trials, controlled clinical trials, and observational studies. Expert opinion based on clinical experience, descriptive studies, or reports of expert committees was also included to discuss aspects of egg freezing not currently rigorously studied. Values The evidence obtained was reviewed and evaluated by the Clinical Practice Guideline (CPG) Committees of the Canadian Fertility and Andrology Society (CFAS) under the leadership of the principal authors. Benefits, Harms, and Costs Implementation of this guideline should assist the clinician to develop an optimal approach in providing counselling for egg freezing while minimizing harm and improving patient outcomes during treatment. Validation These guidelines have been reviewed and approved by the membership of the CFAS and by the CPG Committees of CFAS and The Society of Obstetricians and Gynaecologists of Canada (SOGC). Sponsors CFAS and SOGC. Recommendations 1.Patients should be advised that thawed oocyte survival rates vary, typically between 80% and 90% (Strong, High). 2.Thawed oocytes should be fertilized using intra cytoplasmic sperm injection and patients should be advised that fertilization rates vary, typically between 70% and 80% (Strong, High). 3.Patients should be advised that vitrified oocytes yield fewer blastocysts than fresh oocytes do (Weak, Moderate). 4.Patients should be advised that there are very limited data on live birth rates after social egg freezing, but that the existing data suggest similar clinical pregnancy rates after transfer of embryos obtained by either vitrified or fresh oocytes (Strong, Moderate). 5.Women considering social egg freezing should be advised that the age at which they freeze their eggs and the number of eggs that are frozen impact the probability that these eggs will enhance their fertility (Strong, Moderate). 6.Ovarian reserve testing should be offered to help predict the number of retrievable eggs from a controlled ovarian stimulation cycle and to properly counsel those women at risk of very low oocyte yield (Strong, High). 7.Women considering social egg freezing should be advised that more than one cycle may be required to obtain the number of mature eggs that is desired (Strong, High). 8.Patients considering social egg freezing should be informed about the risks of controlled ovarian stimulation, oocyte retrieval, and pregnancy at a more advanced maternal age (Strong, Moderate). 9.Patients considering social egg freezing should be advised that there is a chance they may not need to use their frozen eggs and that no guarantees can be made that their frozen eggs would produce a viable pregnancy (Strong, High). 10.Women considering social egg freezing should be counselled about the alternative options (Strong, Moderate). 11.Women undergoing social egg freezing should receive sufficient information to provide informed consent (Strong, High). 12.In vitro fertilization centres offering social egg freezing should provide their patients with an estimate of their chances of success. This estimate should not only consider the published medical literature but also should take into account national data regarding social egg freezing and clinic-specific data regarding cumulative live birth rates per oocyte retrieval (Strong, Low).