Lower probability of ongoing pregnancy can be expected when GnRH agonist is used for triggering final oocyte maturation instead of HCG in patients undergoing ovarian stimulation for IVF with GnRH antagonists.

Cryopreservation of human oocytes and embryos is a necessary tool in assisted reproduction treatment that leads to an increased cumulative outcome while decreasing costs. Vitrification is a cryopreservation technique that leads to a glass-like solidification, with rapid cooling of cells or tissues. Nowadays vitrification is claimed to be the future of cryopreservation of human embryos due to improved survival rates and clinical outcomes. This study was conducted at a university clinic to assess the safety and efficiency of vitrification of human zygotes as a routine procedure. A total of 849 pronuclear-stage (PN) zygotes were vitrified between March 2004 and July 2006. During this period, 103 cycles of cryopreserved embryo transfer were completed. In total, 339 PN zygotes were thawed resulting in an 89% survival rate (302 PN zygotes). The mean number of embryos per transfer was 2.2. The pregnancy rate obtained was three times higher (36.9%) than that obtained with the slow-rate freezing method (10.2%) used previously in the same centre. In conclusion, vitrification of human zygotes at the pronuclear stage seems to be a successful and reliable method with favourable outcomes and can be recommended as a routine technique for cryopreservation of human embryos.

During the past decade, macrophage-derived substances such as prostanoids, cytokines, growth factors and angiogenic factors have been detected in the peritoneal fluid of women with endometriosis. In particular, growth-promoting and angiogenic factors are considered to be substantially involved in the pathogenesis of endometriosis. In this study, vascular endothelial growth factor (VEGF), transforming growth factor β (TGF-β) and intercellular adhesion molecule 1 (ICAM-1), substances recently detected in the peritoneal fluid of women with endometriosis, were assessed with regard to their concentrations in different stages of endometriosis and changes of the peritoneal paracrine activity after medical treatment with a gonadotrophin releasing hormone agonist (GnRHa). Peritoneal fluid was obtained from patients with endometriosis during laparoscopy before and after a 4-month treatment with a GnRHa. VEGF, TGF-β and ICAM-1 could be detected in all women presenting with various stages of active endometriosis. After GnRHa therapy, all patients showed significant decreases in mean concentrations of VEGF (194 ± 77 pg/ml), TGF-β (902 ± 273 pg/ml) and ICAM-1 (157 ± 52 ng/ml). Patients with stage III and IV endometriosis (according to the rAFS score) had much higher concentrations of VEGF and TGF-β before treatment compared with those patients with mild endometriosis (rAFS stages I and II). The most striking decrease in concentration was for TGF-β, from 902 pg/ml before to 273 pg/ml after therapy. These results indicate an important role for paracrine activity in the establishment and maintenance of endometriosis. Indeed, treatment with a GnRHa may reduce paracrine activity in the peritoneal cavity via hypo-oestrogenism and provide proof of successful therapy.

The present study is the proof of the concept that GnRH-agonist triggering of final oocyte maturation in combination with elective cryopreservation of 2 PN oocytes offers OHSS risk patients a good chance of pregnancy achievement, while reducing the risk of moderate and severe OHSS.

Except for higher E(2) and LH levels on the day of HCG administration, no positive trend in favour of additional LH was found as defined by treatment outcome parameters.