Why do oestrogens matter: systematic review and meta-analysis assessing GnRH antagonists, considering add-back therapy, for endometriosis-associated pain.

Gonadotrophin-releasing hormone (GnRH) antagonists have been demonstrated to reduce endometriosis-associated pain. Because of the hypo-oestrogenic state they induce, however, higher dosages of GnRH antagonists are not recommended for used long term. This unwanted effect may be eliminated by so-called add-back therapy (ABT). This review was conducted to assess the safety and efficacy of GnRH antagonists, with or without add-back hormonal replacement therapy. Out of the 345 studies selected through the initial search, seven randomized controlled trials were included, comparing different oral GnRH antagonists at varying dosages, from a minimum of 50 mg to a maximum of 200 mg once or twice daily. Women treated with the lowest dose of GnRH antagonists had significantly greater mean pain score reductions from baseline throughout treatment compared with those treated with placebo (odds ratio [OR] -13.12, 95% CI -17.35 to -8.89 and OR -3.08, 95% CI -4.39 to -1.76 for dysmenorrhoea and non-menstrual pelvic pain, respectively). Compatible with the dose-response effect, a positive correlation was found between response rates and adverse event rates. While GnRH antagonists offer an advantage in terms of pain reduction for endometriosis, the more recent literature suggests using GnRH antagonists with ABT, which, while mitigating the hypo-oestrogenic effects of GnRH antagonists, maintain their efficacy, while allowing their long-term use.

Vitrification of human blastocysts for couples undergoing assisted reproduction: an updated review.

Over the past 40 years there has been a worldwide critical change in the field of assisted reproduction technology (ART), leading to the increased application of single blastocyst transfer, which is extremely important to avoid the risks of multiple pregnancy and associated complications for both mother and babies. Indeed, advancements in ART over the last few decades have been obtained thanks to several improvements, including ovarian stimulation, embryo culture conditions and, of course, progress in cryopreservation methods, especially with the application of vitrification. The ability to cryopreserve human embryos has improved significantly with vitrification compared to the initially adopted slow-freezing procedures. Since the introduction of vitrification, it has become the gold standard method to effectively cryopreserve human blastocysts. However, some new protocols are now being explored, such as the short warming procedure and even shorter exposure to the equilibration solution before vitrification, which seem to provide optimal results. Therefore, the main aim of the current narrative review, will be to illustrate the benefit of vitrification as an effective method to cryopreserve the human blastocyst and to illustrate new protocols and variations which in future may increase the performance of vitrification protocols.