雷射輔助孵化囊胚期胚胎使其blastocoele縮小可提高冷凍活產率

以雷射輔助孵化囊胚期胚胎後使其blastocoele體積縮小後，
再施行冷凍可提高胚胎冷凍解凍之著床率及活產率達60%


blastocoele體積過大可能會降低溫度上升或下降之速度，
因而影響玻璃化冷凍之效率與存活率

http://humrep.oxfordjournals.org/content/21/12/3246.long

Artificial shrinkage of blastocoeles using either a micro-needle or a laser pulse prior to the cooling steps of vitrification improves survival rate and pregnancy outcome of vitrified human blastocysts

1. T. Mukaida¹,³, 
2. C. Oka², 
3. T. Goto² and 
4. K. Takahashi¹

+Author Affiliations

1. ¹Hiroshima HART Clinic, Naka-ku, Hiroshima and
2. ²Tokyo HART Clinic, Shibuya-ku, Tokyo, Japan

1. 3To whom correspondence should be addressed at: Hiroshima HART Clinic, 5-7-10 Ohtemchi, Naka-ku, Hiroshima, 730-0051, Japan. E-mail: info@hiroshima-hart.jp

• Received March 30, 2006.
• Revision received June 13, 2006.
• Accepted June 23, 2006.

 

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Abstract

BACKGROUND: Since we reported the first successful birth from a blastocyst vitrified using a cryoloop technique, our results showed that the survival rate of vitrified blastocysts was negatively correlated with the expansion of the blastocoele. We speculated that a large blastocoele may disturb the efficacy of vitrification. Therefore, we evaluated the effectiveness of artificial shrinkage (AS) of blastocoeles before vitrification, on increasing the survival rate of vitrified blastocysts. METHODS: Supernumerary expanded blastocysts on day 5 were vitrified after AS, which was performed by puncturing the blastocoele with a micro-needle, or by making a hole in the blastocoele with a laser pulse. After warming, viable blastocysts (confirmed by re-expansion of the blastocoele) were transferred to patients with hormone replacement cycle. We compared these data with those of our previous report where AS was not carried out. RESULTS: The survival rate was significantly higher (97.2%, 488/502) in this study than that of the previous report (86%). After 266 transferable cycles, 160 patients became pregnant (60.2%), which was significantly higher than our previous results (34.1%, 29/85). The implantation rate was 46.7% (209/448). CONCLUSIONS: Our results revealed that the survival rate and the pregnancy rate of vitrified expanded and hatching blastocysts can be improved by using AS to collapse the blastocele before vitrification.

Figure 2.

AS of expanded blastocyst with a single laser pulse. (a) Before AS. (b) A single laser pulse at the point of the cellular junction of trophectoderm cell at a point away from the inner cell mass (ICM) (circle indicated). (c) Beginning of shrinkage 5s after laser shooting, and arrows indicate the formation of perivitelline space because of contraction. (d) Shrinkage 10s after laser shooting. (e) Shrinkage 20s after laser shooting. (f) Almost complete shrinkage 30s after laser shooting. Magnification is ×400.

Table III.

Clinical outcome of artificial shrinkage using either a micro-needle or a laser pulse

	Micro-needle	Laser pulse
Number of cycles with vitrified blastocyst transfer	240	26
Number of blastocyst vitrified	462	40
Number of vitrified blastocyst survived	449	39
Survival rate (%)	97.2	97.5
Mean number of blastocyst transferred	1.6	1.4
Clinical pregnancies (%)	144 (60)	16 (61.5)
Percentage
Number of implantation	191	18
Implantation rate (%)	46.5	48.6
Number of cycles miscarried (%)	32 (22.2)	3 (18.8)