Photo1…Embryo confirmed on the day following retrieval
Photo2…Two days after of egg retrieval, embryo at cleavage stage (4 cells)
Photo3…Three days after of egg retrieval, embryo at cleavage stage (8 cells)
Photo4…Three days after of egg retrieval, embryo at cleavage stage (8 cells)
This stage of growth is called blastocyst.
Whole of embryo get bigger and zona pellucida get thinner.
In a natural pregnancy, the oocyte would be fertilized in the ampulla of the fallopian tube and would move through the tube towards the uterus as it dividies. An embryo formed under this condition reaches the blastocyst stage just as it reaches the endometrium to implant (5 to 6 days from fertilization). This means that with blastocyst transfer we are putting the embryo back as naturally as possible. (In contrast to embryo transfer at 2 or 3 days after, where the embryo is in the uterus 24 to 72 hours earlier than in the natural cycle.)
■Advantages of blastocysts
■You can choose grew up and fine embryo to transfer!
It is not be able to distinguish whether it would grow to blastocyst after transfer from not, even if it was fine embryo at 2 or 3 days. But grown up to blastocyst embryo can surely be transferred by this method.
■You can prevent multiple pregnancy by reduce the number of embryos to transfer!
We have high rates of pregnancy by blastocyst transfer using grown embryo. This prevents multiple pregnancy(*1) that matter at issue in IVF by reduce the number of embryos to transfer.
(*1)Multiple pregnancy More than two embryos exist in the womb at the same time at pregnancy. To get higher the rates of pregnancy, normally transfer multiple embryos. (Japan society of obstetrics and gynecology determined not more than three.) So twin or triplets would be possible.
■Disadvantage of blastocyst transfer
■It has possibility that not be able to transfer because embryo might not grow to blastocyst.
In case of bad quality or few numbers of embryos, even if it was capable to transfer at few days, has possibility to cancel transfer at 5 days later by not grown to blastocyst.
