The results suggest that artificial shrinkage with pipetting is a simple and effective technique to assist successful cryopreservation of expanded blastocysts by vitrification.

Purpose To evaluate the effect of the size of zona pellucida opening by laser assisted hatching for frozen cleaved embryo that were thawed after both fresh and frozen cleaved embryo transfer cycles failed and were cultured to blastocyst after thawing in patients with multiple implantation failures. Materials and methods Of 101 consecutive procedures

The results of this investigation show that, in vitrified-warmed embryo transfers at the cleavage-stage, the size of zona pellucida thinning area by laser assisted hatching impacts the rate of clinical pregnancy and implantation and that half of zona pellucida thinning significantly increases both of these results compared with quarter of zona pellucida thinning.

This case report describes successful pregnancies after vitrification of human day-7 blastocysts. A total of 16 day-7 blastocysts were vitrified and warmed. All 16 blastocysts survived after warming and were transferred to 11 patients. Six of the women (55%) became clinically pregnant and the implantation rate was 44% (7/16). Among these women, one woman delivered a healthy baby, two pregnancies ended in miscarriage, and three pregnancies are ongoing at 10, 29 and 34 weeks of gestation. This is the first report of successful pregnancies after vitrification of human day-7 blastocysts.

The objective of this study was to investigate whether a change in assisted hatching technique from partial opening to total removal of the zona pellucida improved the outcome of vitrified blastocyst transfer. This was a preliminary observational study conducted from November 2003 to April 2006. Partial opening using acid Tyrode's solution was performed in 45 cycles, while total removal using a laser and mechanical pipetting was performed in 57 cycles. The clinical pregnancy, implantation, and delivery rates were higher in the total removal group than in the partial opening group (67% versus 42%, P < 0.02; 55% versus 30%, P < 0.01; 56% versus 36%, P < 0.04, respectively). These results suggest that total removal of the zona pellucida is associated with higher pregnancy, implantation and delivery rates compared with partial opening for vitrified blastocyst transfer.