AN OVERVIEW OF BLASTOCYST TRANSFER AT A DENVER FERTILITY CLINIC

Blastocyst Transfer Overview

In the blastocyst transfer process, embryos are cultured in the lab up to the blastocyst stage, and then a transfer to the uterus is performed. Typically it takes 5 -6 days after fertilization for the embryo to reach the blastocyst stage and it is the most advanced stage of development in embryo culture before placing the embryos in the uterus during the IVF process.  Most patients undergoing the IVF process at Rocky Mountain Fertility Center will have a blastocyst transfer.

What is a Blastocyst?

A blastocyst is the name given to an embryo five to six days after fertilization when it has reached certain stages of development. At the blastocyst stage the embryo starts differentiating by forming cells that make the placenta and grouping together cells that form the baby. With a blastocyst, you can see a clump of cells (called the inner cell mass), which will become the baby, as well as the cells surrounding this clump (called the trophectoderm) that will become the placenta.

Advantages of Blastocyst Transfer

In patients with multiple good quality embryos after egg retrieval blastocyst transfer is often considered. A blastocyst transfer often results in higher pregnancy rates as only the best patients with multiple good quality embryos are selected to proceed with a blastocyst transfer. The procedure for blastocyst transfer is similar to a normal embryo transfer, the only difference being that the embryos have been given more time to develop in the embryo lab. This extra time allows the embryologists additional time of embryo observation to better select the embryos most likely to develop into a healthy baby.  It is important to know that a blastocyst transfer is not about making a better embryo, it’s about improving the ability of the embryo lab to pick out the strongest and best embryo, i.e. weeding out the weak embryos from the ones more likely to implant. Theoretically, an embryo that dies in the laboratory before it develops into a blastocyst would also not have continued to develop in the uterus. Therefore, theoretically,  by observing embryos longer we can pick out the embryos most likely to continue to grow.

Our Colorado fertility clinic specialists will help you decide if a blastocyst transfer is right for you, however this decision can only be made during the IVF cycle based on embryo quality.  A recommendation for blastocyst transfer is typically made when there are four or more high quality embryos found on the third day following the egg retrieval.  If there are fewer than four good quality embryos present, particularly in women over the age of 38, it may be recommended to consider transferring all good quality embryos embryos on day three.  The options for blastocyst transfer are carefully discussed between the patient, doctor and the IVF lab, during the IVF cycle. . An “embryo report” is called to the patient each day during the IVF process to update the patient on the progress and growth of their embryos.   The options are thoroughly discussed including recommendations for day 3 or day 5 (blastocyst) transfer as the embryos grow.

Extra and Remaining Blastocysts

Any extra blastocysts that are not transferred during the process can be cryopreserved, or vitrified.  A embryologist in the laboratory performs this procedure.  One of the advantages of vitrifying at the blastocyst stage is that only good quality embryos are frozen limiting the number of frozen embryos that are stored for a patient. Survival of vitrified embryos after the thaw is quite high.