Elective cryopreservation of embryos at the pronucleate stage in women at risk of ovarian hyperstimulation syndrome may affect the overall pregnancy rate

Effect of metformin taken in the ‘fresh’in vitrofertilization/intracytoplasmic sperm injection cycle upon subsequent frozen embryo replacement in women with polycystic ovary syndrome

“…Elective cryopreservation of embryos is a common strategy employed to reduce the risk of developing OHSS in the face of exuberant follicular response to superovulation and is associated with a reduction in severe OHSS whilst not compromising pregnancy rates (Pattinson et al, 1994;Ferraretti et al, 1999;Vyjayanthi et al, 2006;Sills et al, 2008). In the present study we observed a significantly higher LBR among such women who had taken metformin in the fresh IVF/ICSI and had elective cryopreservation.…”

Slow freezing, vitrification and ultra-rapid freezing of human embryos: a systematic review and meta-analysis

“…With slow freezing, a wide range of clinical pregnancy rates have been reported, depending on cell stage, methodology used and replacement protocols. Clinical pregnancy rates with pronuclear-stage embryos have ranged from 10% to 44% (Salumets et al, 2003;Schroder et al, 2003;Seelig et al, 2002;Senn et al, 2000;Tummon et al, 2006;Vyjayanthi et al, 2006). Pregnancy rates of 6-54% have been reported with cleavage stage embryos (Chi et al, 2002;Edgar et al, 2007;Kuwayama et al, 2005;Nagy et al, 2005;Rienzi et al, 2005;Salumets et al, 2003Salumets et al, , 2006Van der Elst et al, 1997;Warnes et al, 1997;Wang et al, 2001;Ziebe et al, 1998).…”

“…It should be noted, however, that considerable improvement in clinical outcomes with slow freezing of blastocysts has been observed in recent years. A better understanding of cryobiological principles, enhanced embryo culture systems and resultant improved blastocyst quality may also have contributed towards this upward shift (Chi et al, 2002;Gardner et al, 2000;Marek et al, 2001;Mauri et al, 2001;Nagy et al,2005;Senn et al, 2000;Veeck et al, 2004;Vyjayanthi et al, 2006).…”

Pronuclear embryo cryopreservation experience: outcomes for reducing the risk of ovarian hyperstimulation syndrome and for fertility preservation in cancer patients

“…These studies, however, are limited by a lack of a comparison group [15] or details of the comparison group [16][17][18][19][20]. The choice of comparison group for this study is not necessarily to serve as a control, but is provided only to provide the background for the center's general practice and IVF outcomes.…”

“…dosage or type of medications [9,10], administration of intravenous albumin [11,12], dopamine agonists [13,14] and avoidance of ET, and thus pregnancy, immediately after stimulation with freezing of embryos for subsequent use [12,[15][16][17][18][19][20][21][22][23].…”