Blastocyst Info

Here is some info about the day 5 blastocysts from our office. :)




Blastocyst and Extended Culture

The continued refinement of the lab and culture media offers greater opportunity for infertile couples. The introduction of blastocyst culture is the latest important step that helps increase implantation rates while minimizing multiple births. Recent studies confirm the fact that blastocyst transfers on day 5 or day 6 have essentially equivalent pregnancy rates if not greater than compared to embryo transfers on day 3. However, the advantage’s with blastocyst culture is the transfer of significantly fewer embryos while maintaining these pregnancy rates.

Traditionally, embryos have been transferred to the uterus on the second or third day of development after in vitro fertilization. New culture media now are designed to take into account the changing needs of the developing embryo in vitro allowing laboratories to extend culture of these embryos for up to six days.

After five to 6 days of growth, the cells of the embryo should have divided many times over, and have begun to differentiate by function. The embryos that survive to this stage of development are usually strong, healthy, and robust. They are now called blastocysts. At this point, the blastocyst contains around 100 cells that are formed into 2 distinct types, the inner cell mass that goes on to make the fetus and the surface cells called the trophectoderm that goes on to make the placenta.


What Are the Benefits of Blastocyst Transfer?

Blastocyst culture allows for better selection of an embryo for transfer as described above which leads to higher implantation / pregnancy rates and a reduction in high order multiple births. This means that various obstetrical complications that may arise from multiple pregnancies can be minimized. It is especially important in helping patients avoid having to make the difficult personal and ethical decisions regarding selective reduction. Pacific Northwest Fertility and IVF Specialists recommend transferring 1-2 blastocysts.

Is Blastocyst Culture and Transfer for Everyone?

Candidates for a blastocyst transfer typically are younger and have a large number of eggs. On average those having 8 or more embryos on day 3 are potential candidates for blastocyst culture. Other candidates may be those patients in which a multiple pregnancy would put them at an extreme risk. Unfortunately, blastocyst culture does not improve the quality of an embryo. Most poor quality embryos will not become blastocyst and even some high quality embryos will never become blastocysts. Finally there are those rare patients whose embryos develop very poorly in the blastocyst culture media and therefore need to be transferred on day 3.