American Society for Reproductive Medicine 65th Annual Meeting(2009.10.17-21 Atlanta）
Are there any differences for hatching by assisted hatching to blastocyst between at near or the opposite site of the ICM.
Laboratory, Osaka New ART Clinic, Osaka, Japan;
Doctor, Osaka New ART Clinic, Osaka, Japan.
It has been observed that natural hatching site develops in close proximity to the ICM of blastocyst (BL) in humans. The aim of the study is to assess the hatching phenomena of BLs when assisted hatching (AHA) is performed at the different site of zona pellucida.
Materials and Methods
Candidates for this study are the patients who got pregnant and had children between June 2004 and November 2006, whose BLs were cryopreserved at day 5, and who and whose husband did not wish to use residual BLs any more. With informed consent patients allow us to use them for the following experiment before getting rid of them. Fourteen BLs with 3BB (Gardner's classification) were included in the study. Those BLs were randomly divided into two groups; laser AHA (ZILOS-tk;Hamilton Thorne) was performed at near the ICM (ICM group) or at the opposite side of the ICM (OP group). AHA was done 30 min after thawing them. BLs were assessed for morphology by microscopy at 1, 2, 3, 4, 24, and 48 hr after thawing. All data were analyzed via Fisher's exact test. IRB approval was obtained.
Natural hatching occurred at the AHA site of all BLs. Extrusion of the ICM of ICM group (100%, 7/7) was significantly higher than that of OP group (14.3%, 1/7). Similarly, completely hatched BL of ICM group (85.7%, 6/7) was significantly higher than that of OP group (14.3%, 1/7). Average time to be able to confirm ICM under microscopy was 17.9 min after thawing (range 0 to 25 min). Average perivitelline space at the time of ICM confirmation was 22.3μm, and that of 30 min after thawing was 19.3μm.
AHA performed at near the ICM is better for hatching compared with the opposite side of the ICM. AHA at the opposite site of the ICM might rather interfere hatching. To confirm the existence of the ICM followed by AHA, we.