BACKGROUNDLetrozole is the third-generation aromatase inhibitor (AI) most widely used in assisted reproduction. AIs induce ovulation by inhibiting estrogen production; the consequent hypoestrogenic state increases GnRH release and pituitary follicle-stimulating hormone (FSH) synthesis.METHODSA systematic search of the literature was performed for both prospective and retrospective studies. Meta-analyses of randomized clinical trials (RCTs) were performed for three comparisons: letrozole versus clomiphene citrate (CC), letrozole + FSH versus FSH in intrauterine insemination (IUI) and letrozole + FSH versus FSH in IVF. In the absence of RCTs, non-randomized studies were pooled.RESULTSNine studies were included in the meta-analysis. Four RCTs compared the overall effect of letrozole with CC in patients with polycystic ovary syndrome. The pooled result was not significant for ovulatory cycles (OR = 1.17; 95% CI 0.66–2.09), or for pregnancy rate per cycle (OR = 1.47; 95% CI 0.73–2.96) or for pregnancy rate per patient (OR = 1.37; 95% CI 0.70–2.71). In three retrospective studies which compared L + FSH with FSH in ovarian stimulation for IUI, the pooled OR was 1.15 (95% CI 0.78−1.71). A final meta-analysis included one RCT and one cohort study that compared letrozole + gonadotrophin versus gonadotrophin alone: the pooled pregnancy rate per patient was not significantly different (OR = 1.40; 95% CI 0.67–2.91).CONCLUSIONSLetrozole is as effective as other methods of ovulation induction. Further randomized-controlled studies are warranted to define more clearly the efficacy and safety of letrozole in human reproduction.

Flutamide at 125 mg daily during 12 months was the minimum effective dose to diminish hirsutism in patients with polycystic ovary syndrome or with idiopathic hirsutism.

Treatment with insulin-sensitizing agents is a relatively recent therapeutic strategy in women with polycystic ovary syndrome (PCOS) and insulin resistance. The key areas addressed in this review include PCOS and the development of type 2 diabetes mellitus and gestational diabetes, as well as the use of insulin-sensitizing agents, particularly metformin, in the management of infertility in obese and non-obese PCOS women. Treatment with metformin in PCOS women undergoing IVF and the use of metformin during gestation will be discussed. The challenge for the health care professional should be the appropriate utilization of pharmacotherapies to improve insulin sensitivity and lower circulating insulin levels resulting in beneficial changes in PCOS phenotype. Further research into the potential role of other insulin-sensitizing agents, such as pioglitazone and rosiglitazone, in the treatment of infertile women with PCOS is needed.

Barcelona and Professor of UAB. He is also co-founder of the interest group on Reproductive Endocrinology of the Spanish Fertility Society and President of the National Spanish Fertility Society Meeting held in Barcelona in 2014. KEY MESSAGE Pending new evidence, it would be advisable not to include chronic endometritis in the initial baseline study before assisted reproduction in order not to delay other assisted reproduction treatments. ABSTRACT (max. 200) Chronic endometritis (CE) is a pathology often associated with reproductive failure, but there are still no clear recommendations on whether its inclusion in the initial study of the infertile couple is necessary. In this discussion paper, based on a SWOT (strengths, weaknesses, opportunities, threats) analysis, the different aspects of the repercussions of CE in fertility are evaluated. To avoid possible subjectivity in the analysis and results of this study, researchers followed Oxford criteria for the evaluation of evidence. The results from the evaluation of the reviewed bibliography seem to indicate that, pending new evidence, it would be advisable not to include CE in the initial baseline study before assisted reproduction in order not to delay other assisted reproduction treatments. However, it would be advisable in those cases of repetitive implantation failure and pregnancy loss after having undergone IVF with viable embryos and before continuing with costly reproductive processes, since results could be improved. The development of randomized studies that assess the impact of antibiotic treatment as a possible therapeutic option in infertile women with CE as well as the possible impact on endometrial microbiota and receptivity/implantation would allow for the establishment of more precise clinical guidelines in this regard.

Obese women have lower pregnancy rates than normal-weight women undergoing assisted reproductive treatment. We conducted a pilot study to evaluate whether a 12-week diet and exercise intervention before an IVF cycle would influence pregnancy rates in obese women. Forty-one patients were enrolled in this study. They were randomly allocated to two groups: an intervention group (n = 21), who underwent an individualized diet and physical exercise programme supervised by a dietician, and a control group (n = 20), who started IVF with no previous intervention. The primary outcome was clinical pregnancy rate after a single treatment cycle. Mean weight loss in the study group after the intervention was 5.4 kg (range 1.1-14.6 kg). The study and control groups had similar total FSH consumption, number of oocytes and embryos obtained, and number and quality of embryos transferred. There was a non-significant trend towards a higher clinical pregnancy rate after fresh embryo transfer (66.7% versus 41.2%). The intervention group had a significantly higher cumulative live birth rate (61.9% versus 30%, P = 0.045) (odds ratio for intervention group, 3.8; 95% confidence interval, 1.03 to 13.9) The data suggest that weight loss resulted in a significantly increased cumulative live birth rate.