Mukaida T, Oka C, Goto T, Takahashi K
Hiroshima HART Clinic, Naka-ku, Hiroshima, Japan.
Hum Reprod. 2006 Dec;21(12):3246-52. doi: 10.1093/humrep/del285. Epub 2006 Aug 26.
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.
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.
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).
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.
自从我们报道了首例使用冷冻环技术冷冻囊胚后成功分娩的案例以来，我们的研究结果表明，冷冻囊胚的存活率与囊胚腔的扩张呈负相关。我们推测，较大的囊胚腔可能会干扰玻璃化冷冻的效果。因此，我们评估了在玻璃化冷冻前对囊胚腔进行人工缩小（AS）对提高冷冻囊胚存活率的有效性。
在第5天对多余的扩张囊胚进行人工缩小（通过用微针穿刺囊胚腔或用激光脉冲在囊胚腔上打孔）后进行玻璃化冷冻。解冻后，将存活的囊胚（通过囊胚腔重新扩张确认）移植到接受激素替代周期治疗的患者体内。我们将这些数据与我们之前未进行人工缩小的报告数据进行了比较。
本研究中的存活率（97.2%，488/502）显著高于之前报告中的存活率（86%）。在266个可移植周期后，160名患者怀孕（60.2%），这显著高于我们之前的结果（34.1%，29/85）。着床率为46.7%（209/448）。
我们的结果表明，在玻璃化冷冻前使用人工缩小方法使囊胚腔塌陷，可以提高冷冻扩张期和孵化期囊胚的存活率和妊娠率。
