Why embryos stop developing

The most obvious advantage is that fewer embryos may be transferred since the embryos are pre-selected for superior developmental capacity. Most programs that perform blastocyst stage transfer will transfer two embryos. When transferring two embryos with superior developmental potential, the possibility of triplets, quadruplets, etc. This is particularly important for younger patients or donor egg recipients who are at high risk for triplets or quadruplets following the transfer of three or more embryos.

Another advantage to blastocyst stage transfer is that although some embryos technically reach the blastocyst stage, there may be too few stem cells to make a baby. When embryos are cultured to the blastocyst stage in the laboratory, these developmentally comprised embryos can be identified and their transfer avoided. In addition to providing therapeutic value, extended embryo culture can provide important diagnostic information.

Extended embryo culture can answer this question by determining the rate of embryo growth and the percentage of embryos that reach the blastocyst stage. This information is useful to everyone undergoing IVF, but is particularly important for older patients with few eggs.

If the embryos develop slowly or fail to reach the blastocyst stage, this information can be a deciding factor for patients willing to pursue the option of donor eggs.

Many patients worry that they will end up without any embryos for transfer. In the rare case where no embryos reach the blastocyst stage by the sixth day of development, this information can be very useful in deciding the next course of action, particularly if the couple has had a previous IVF failure following a Day 3 transfer.

This is for informational purposes only and does not constitute medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition.

You May Also Like. Episode 1 in 4 Struggle with Infertility: The Doctors. Is 15 the Best Number for Egg Retrieval? Failure to achieve a successful pregnancy with euploid embryos can be generally grouped into three major areas: embryonic, uterine, and systemic.

The development of an early embryo is a complex and highly synchronized series of events to prepare it for attaching to and invading the lining of the uterus. The process starts at fertilization with single cell called a zygote, which develops over 5 days into a cell hollow ball, called a blastocyst.

It is a blastocyst that will attach to and implant in the lining of the uterus. Our 46 chromosomes contain about 25, genes that have to function properly to have the embryo develop successfully. I think of it like a symphony of the genes being turned on and off at specific times. If the timing of this is off, just like an orchestra, things will go badly. Basic science studies suggest that energy function metabolism of the embryo is also a likely cause of failure, but this too cannot be practically measured in the clinical lab.

Basic science studies and our clinical experience suggest that early embryo development can be altered by our clinical and laboratory environment. It is clear that the type of follicular stimulation in an IVF cycle will impact the oocyte and embryo. The correct use of supporting medications LH or low dose-hCG, growth hormone, androgens may be beneficial to development of the growing follicle and egg for some individuals.

However, incorrect use of these medications can be detrimental. The type of trigger shot used to prepare for egg retrieval hCG or GnRH agonist may have an impact on egg quality also, but who may benefit from which drug and to what degree there is an advantage remain unclear. As you can imagine, the laboratory environment plays a huge role in how the embryos will perform. Culture media has evolved tremendously over the last 30 years, starting from simple media adequate for most cells to the variety of high quality embryo-specific, commercially made media that we currently use.

There are several high quality culture media available that work well however, constant quality testing is essential to make sure a chosen media performs optimally. The incubators that the embryos grow in and their function are clearly a major factor.

Most high quality practices are using the small bench top incubators which do a better job of maintaining the chemical environment and temperature stability for the embryos to grow in. However, these high-tech devices must be constantly monitored, as subtle changes can impact embryo performance.

Simple things like how often the embryos are evaluated, under what conditions, and the time it takes to do so can tremendously impact embryo performance.

The trend is clearly towards evaluating the embryos less frequently. It should not go without saying that technical competence of the people in the laboratory is essential for good outcomes. However, those of us who have done inspections have seen a wide array of skill levels. In ICSI intracytoplasmic sperm injection- injecting the sperm in to the egg for example: was the procedure done at the correct time?

What kind of sperm was selected? All the cells are doing the same job and are identical at this point. An embryo that continues to grow to Day 5 becomes a blastocyst with hundreds of cells. The cells start to specialize into different kinds of cells and a cavity forms in the middle which is filled with fluid. Q: Why are blastocysts important? A: An embryo that has reached the blastocyst stage at around Day 5 of development has a good chance of making a baby.

If an embryo reaches this stage, we know that the embryo is still growing and is a good choice for transfer to the uterus. It is especially useful to overcome many issues surrounding male factor fertility. Q: When my embryologist talks about normal fertilization the day after my retrieval what does that mean? A: A normally fertilized egg has 2 pronuclei that the embryologist can view under the microscope. One pronucleus contains the male genetic material and one contains the female genetic material.

Q: What is a morula? A: A morula is the stage of development before a blastocyst is formed. The cells on day 3 are separate and round and on day 4 they start to squeeze together compaction so that the edges of the cells are not clear.

This is the morula stage. Q: Why do blastocysts have a higher implantation rate? A: Typically about half of the embryos will continue growing to Day 5.

Therefore by watching them grow until Day 5 we are able to get much more information about the viability and quality of each embryo. This helps us to choose the ones more likely to lead to a baby.

Biologically, in a natural pregnancy cycle, at around 5 days old the embryo has entered the uterus and is at the appropriate stage for implantation in the uterus. Q: What is an expanded blastocyst? A: An expanded blastocyst is an embryo that has grown to 5 or 6 days old and has become a hollow ball of cells taking in fluid from the external environment.