What If No Embryos Develop After Fertilization? Understanding IVF Embryo Attrition

What if no embryos develop after fertilization during IVF? It’s a distressing scenario, but it’s more common than most people think. The truth is, not all fertilized eggs are guaranteed to grow into healthy embryos. There are many factors that influence the success of embryo development, such as IVF attrition rate. In this blog, we’ll explain why attrition happens and what you can do next.

Why Don’t All Embryos Develop?

After the egg and sperm retrieval, your clinic places both gametes in a petri dish for fertilization to take place. In ICSI treatment, an embryologist injects the healthy sperm cells directly into the cytoplasm of the egg cells.

Embryos are allowed to grow in an incubator, which is a machine that mimics the conditions inside the female reproductive tract, such as temperature, oxygen pressure, and so on. Despite these near-perfect conditions, some embryos simply don’t make it to the blastocyst stage.

Understanding the IVF Attrition Rate

What if no embryos develop after fertilization? Regardless of your IVF clinic’s success rates, not every embryo will successfully survive the IVF process and result in a baby. 

At each stage of IVF treatment, some eggs/embryos are lost during the process. This is a natural and unavoidable part of the fertilization process. This means the number of eggs retrieved will not amount to an equal number of embryos.

The rate at which these eggs or embryos decrease during the IVF process is called the attrition rate. The attrition rate dictates how many embryos survive the entire IVF process, from egg retrieval to fertilization.

Note that the numbers and percentages provided in the above table are general estimates based on data observed by fertility clinics. Actual outcomes may vary depending on several factors, including the patient’s overall health, the quality and quantity of eggs retrieved, and the expertise of the clinic and its medical team.

The table illustrates the attrition rate as a general percentage of eggs that survive each stage of the IVF process. So if you had 20 eggs retrieved, you may only have 3 to 6 embryos develop into blastocysts. If you choose to PGT test these embryos, you may discover that only 1 or 2 of your blastocysts are euploid.

Some patients experience better attrition rates than others, depending on factors like egg and sperm quality, age, and the presence of genetic defects.

What is Embryo Arrest? Identifying Why Embryos Stop Growing

When embryos stop growing in the lab, it is called embryonic arrest. Embryo arrest occurs when an embryo stops dividing for twenty-four hours and can happen at any stage during the IVF stage. Only 40 to 50% of embryos make it to the blastocyst stage.

Embryo arrest is an important part of the fertilization process, as it prevents abnormal or poor-quality embryos from developing into blastocysts. If no embryos develop after fertilization, it is likely that most of your embryos succumbed to embryonic arrest. Here are the most common causes of embryo arrest:

Chromosomal Errors

Embryos that divide abnormally during the cleavage stage can cause an uneven distribution of chromosomes within the cells, which can halt their growth. 

Chromosomal abnormalities and errors are a very common cause of embryo arrest. In fact, according to a study published in the International Journal of Fertility and Sterility, almost 70% of arrested embryos display some type of chromosomal defect. Common chromosomal errors include:

Aneuploidy

An abnormal number of chromosomes present.

Polyploidy

More than one full set of chromosomes present.

Mosaicism

A combination of both aneuploidy and polyploidy.

While chromosomal errors can make an embryo arrest, this isn’t always the case. These embryos can still develop into blastocysts. PGT can help identify such embryos.

Cell Division Errors

Normally, cells within the embryo divide from one to two and distribute their chromosomes equally. In rare instances a cell may accidentally divide into three. This phenomenon is called Direct Uneven Cleavage (DUC) and can potentially cause embryos to arrest.

Other times, the embryo’s cells stop dividing, but the nucleus continues to replicate. This increases the number of chromosomes present and can cause the embryo to arrest.

Poor Embryo Development

Low-quality embryos may contain defects that make development difficult. The embryo can sometimes stop dividing due to these defects or undergo apoptosis (instructed cell death).

Apoptosis usually helps embryos kill off any defective or damaged cells from it. Large-scale apoptosis can stop the embryo from developing altogether, as there aren’t enough healthy cells to carry on.

Mitochondrial Function

The mitochondria is the powerhouse of the cell. This power supply produces a vital molecule called adenosine triphosphate, or ATP. If there is damage to the mitochondrial DNA, the embryo will not be able to produce enough ATP and will not be able to carry out the necessary functions for development.

Advanced maternal age can be one of the causes of mitochondrial dysfunction, as the quality of eggs declines with age and impairs mitochondrial DNA.

In the first two days after fertilization, the embryo relies on the egg to keep growing. Between days two and three, its genome, or individual genetic material, activates. Embryonic genome activation (EGA) is a critical event in which the embryo’s own genes (zygotic genome) begin to be expressed, taking over from the maternally provided factors. Now, the embryo doesn’t need to rely on the egg—it can keep growing through its own cellular activity.

The embryo can’t function without making the maternal-to-zygotic transition or switch to embryonic genome control. Approximately 10% of embryos don’t survive this change.

No Embryos Develop After Fertilization: What’s Next?

Embryo arrest is difficult to deal with, as it can make you feel helpless and not in control. Remember, every IVF cycle is different, and your eggs will be different too. It is definitely possible for women who have experienced a 100% attrition rate to gain IVF success in future attempts.

In some cases, lab conditions or protocols may negatively impact embryo development. Although some fertility clinics offer IVF at appealingly low prices, it’s important to prioritize experience, lab quality, and transparency. Even a single careless error in the lab could cost you perfectly healthy embryos. Choose a reputed IVF centre in Mumbai, like Corion Fertility Clinic, for safe and effective IVF treatment.

Here’s what you can do to make your next IVF cycle a success:

Donor Eggs

If you have poor egg quality because of advanced maternal age and have experienced fertilization failure multiple times, switching to using donor eggs might be the best option.

Donor Sperm

While egg quality plays a major role in embryo development, sperm health is equally important. Issues like DNA fragmentation or poor motility can also contribute to embryo arrest. Donor sperm could help lower embryo arrest rates.

Adjusting Treatment Protocol

Every IVF journey is unique. A failed IVF cycle isn’t the end—it can open up new doors for success. After your first cycle, your IVF specialist can adjust your treatment protocol to target your fertility problems more efficiently. Advances in fertility treatments and improved lab protocols could very well make your dream of parenthood a reality in the future.

At Corion Fertility Clinic, we believe that every patient deserves honesty and transparency. Our embryologists do their best to provide you with as much information as they can. Get a second opinion from a trusted clinic that has helped thousands of couples conceive. Book an appointment today.

Frequently Asked Questions:

Q. Why did none of my embryos make it to blastocysts?

A. Embryos with chromosomal abnormalities or poor embryo quality often do not make it to the blastocyst stage.

Q. Can my embryo fall out after IVF transfer?
A. No, your embryo cannot fall out after IVF transfer, as it is placed directly inside the uterus.

Q. How to prevent IVF attrition?
A. Unfortunately, IVF attrition is a natural part of the process. A reputed clinic like Corion Fertility Clinic can minimize the number of embryos lost but not prevent it completely.

Q. Do all fertilized eggs become blastocysts?
A. No, not all fertilized eggs become blastocysts. Approximately 40–50% of embryos make it to the blastocyst stage due to the attrition rate in IVF treatment.

Q. How many IVF attempts are too many?
A. While there’s no maximum number of IVF cycles you can undergo, most fertility specialists will recommend you explore other options after three to six IVF attempts.