Does Embryo Biopsy Affect Your Chance of a Live Birth?

Embryo biopsy is an important part of certain fertility treatments, including preimplantation genetic testing for aneuploidy (PGT-A). It allows embryologists to remove a small number of cells from an embryo so that its chromosomes can be examined before transfer.

However, a common question among patients considering IVF is whether removing these cells could affect the embryo’s ability to develop and result in a live birth.

At Pyramedicine, we believe that understanding the evidence is an essential part of making informed fertility decisions. Research published in Fertility and Sterility in 2013 examined whether embryo biopsy itself affects the chance of a live birth, comparing embryos that underwent biopsy with embryos that were left untouched.

The findings highlighted an important distinction: the stage at which an embryo is biopsied may matter.

What Is Embryo Biopsy in IVF?

Embryo biopsy is a laboratory procedure in which an embryologist removes a small sample of cells from an embryo. The sample can then undergo genetic analysis to investigate specific genetic conditions or chromosome abnormalities, depending on the test being performed.

For example, PGT-A examines the number of chromosomes in sampled cells to help identify embryos with chromosome-number abnormalities.

There are two commonly discussed approaches to embryo biopsy:

Day-3 biopsy: Cleavage-stage biopsy

On day 3 after fertilisation, the embryo is typically at the cleavage stage. It consists of a relatively small number of cells, known as blastomeres.

Day-3 biopsy traditionally involves removing one blastomere for genetic analysis. Because the embryo has fewer cells at this stage, removing one represents a relatively substantial proportion of its total cell population.

Day-5 biopsy: Blastocyst-stage biopsy

By day 5 or 6, a developing embryo may have reached the blastocyst stage. It contains different groups of cells, including the inner cell mass, which contributes to the fetus, and the trophectoderm, which contributes primarily to the placenta and associated tissues.

Blastocyst biopsy generally involves removing several trophectoderm cells while aiming to leave the inner cell mass undisturbed.

This approach allows the laboratory to obtain a sample for genetic testing without directly sampling the inner cell mass. However, biopsy is still an invasive procedure, and it cannot be assumed to be entirely risk-free.

Does Embryo Biopsy Reduce the Chance of a Live Birth?

A study by Scott and colleagues, published in Fertility and Sterility in 2013, investigated whether embryo biopsy affected the likelihood of a live birth.

Rather than simply comparing different groups of patients, the researchers compared biopsied and unbiopsied embryos transferred into the same patient. This design helped account for some differences between patients that could otherwise influence the results.

The study examined two biopsy techniques:

• Day-3 biopsy, involving the removal of one blastomere.
• Day-5 biopsy, involving the removal of approximately four to five trophectoderm cells from a blastocyst.

The researchers subsequently used DNA fingerprinting to identify which embryo resulted in a live birth.

What did the researchers find?

The results differed according to the stage at which biopsy was performed.

Source: Scott RT Jr and colleagues, 2013. Outcomes are reported per embryo transferred, not per patient or IVF cycle.

1. Day-3 biopsy was associated with a lower live birth rate

Among the embryos undergoing day-3 biopsy, 30.4% resulted in a live birth, compared with 50.0% of the unbiopsied embryos.

This represents an absolute difference of 19.6 percentage points. The relative reduction was approximately 39% compared with the unbiopsied embryos.

The reported P-value of 0.02 indicated a statistically significant difference in this study.

These findings suggest that removing a blastomere at the cleavage stage may adversely affect an embryo’s developmental potential. However, the results came from a specific study population and should not be interpreted as a precise estimate of risk for every patient or laboratory.

2. Day-5 biopsy showed no statistically significant reduction

The findings were different for blastocyst-stage biopsy.

Approximately 51% of biopsied embryos resulted in a live birth, compared with approximately 54% of unbiopsied embryos. The difference was not statistically significant, with a reported P-value of 0.804.

Importantly, this does not prove that day-5 biopsy has no effect or carries zero risk. It means that the study did not detect a statistically significant difference between the two groups.

The results are reassuring about the approach used in this trial, but they do not establish that every biopsy procedure is harmless or that outcomes are identical across all clinics, patients and laboratory techniques.

Why Might Day-5 Biopsy Have Different Results From Day-3 Biopsy?

One possible explanation relates to how embryos develop between day 3 and the blastocyst stage.

At day 3, an embryo has relatively few cells. Removing one blastomere therefore removes a meaningful proportion of its cells.

By day 5, a blastocyst contains more cells that have begun to differentiate into distinct populations. Trophectoderm biopsy samples cells from the outer layer, while aiming to preserve the inner cell mass.

This difference in developmental stage and biopsy technique may help explain why the study found different outcomes for day-3 and day-5 biopsy.

However, the trial was not designed to establish the precise biological mechanism behind the findings. We should therefore avoid concluding that the biopsy stage alone explains every difference in outcome.

In contemporary IVF practice, blastocyst-stage trophectoderm biopsy is generally preferred when embryo biopsy is indicated for PGT. The decision should still take account of the clinical circumstances, the laboratory’s expertise and the patient’s treatment goals.

What Are the Limitations of This Study?

Although the findings are informative, several limitations are important when applying them to current fertility treatment.

1. The participants were a selected group

The trial included women under 35 with normal ovarian reserve. Its findings may not apply directly to patients of different ages, those with reduced ovarian reserve or those with other fertility-related factors.

2. The two biopsy techniques were not directly randomised against each other

The study examined day-3 and day-5 biopsy separately. It was not a direct randomised comparison of the two techniques, so the results cannot establish the exact difference in risk between them.

3. The study did not measure cumulative live birth

The reported outcomes concerned live births per embryo transferred. They did not establish whether biopsy affected the cumulative chance of having a baby from all embryos obtained during an egg-retrieval cycle.

These are different outcomes. A treatment could affect the likelihood of success per embryo transfer without necessarily having the same effect on the overall chance of a live birth after all available embryos have been used.

4. The study did not establish whether PGT-A improves IVF success

This is a particularly important distinction.

The researchers investigated the potential effect of biopsy on embryo reproductive potential. Chromosome results were not used to select embryos for transfer in the way they would be during PGT-A treatment.

Consequently, the trial does not answer whether PGT-A improves the chance of a live birth compared with IVF without PGT-A.

To assess that question, we need evidence comparing treatment strategies that include genetic testing and embryo selection against strategies that do not.

Does This Mean Everyone Should Have PGT-A?

No. These findings do not mean that every IVF patient needs PGT-A.

PGT-A may provide useful information about chromosome-number abnormalities in sampled cells and can help inform embryo selection in appropriate circumstances. However, its potential benefits depend on the individual patient and their treatment context.

It is also important to understand what PGT-A cannot do:

• It does not repair chromosome abnormalities or make an abnormal embryo normal.
• It does not create additional embryos.
• A result indicating a chromosomally normal embryo does not guarantee implantation, pregnancy or live birth.
• It is not a comprehensive test for every inherited genetic condition.
• It does not necessarily improve cumulative live birth rates for every patient undergoing IVF.

The decision to use PGT-A should therefore be based on individual circumstances, the expected benefits and limitations, the available evidence and discussion with the treating fertility team.

What Does This Mean for Patients Considering IVF in Egypt?

At Pyramedicine, we help international patients explore fertility treatment options in Egypt and understand the practical and clinical questions involved in planning treatment abroad.

When considering IVF with embryo biopsy or PGT-A, it is worth discussing the following questions with your fertility specialist:

• Why is embryo biopsy or genetic testing being recommended in your particular case?
• Will the clinic use blastocyst-stage trophectoderm biopsy?
• What are the potential benefits and limitations of PGT-A for your circumstances?
• How does the clinic explain its results, including embryos with inconclusive or mosaic findings where relevant?
• What costs are included in the treatment package, and are biopsy, genetic laboratory testing, medication and embryo freezing charged separately?
• How will the clinic coordinate treatment, results and follow-up if you are travelling from abroad?

The answers will depend on the treatment plan and the provider. We encourage patients to seek clear explanations before making a decision, rather than assuming that a more complex IVF procedure will necessarily produce a better outcome.

If you are considering fertility treatment in Egypt, our team can help you explore the available options and understand the practical steps involved in arranging care.

Frequently Asked Questions

Does embryo biopsy damage the embryo?

Embryo biopsy is an invasive procedure and may affect an embryo’s developmental potential. In the 2013 Scott et al. study, day-3 biopsy was associated with a significantly lower live birth rate per embryo, while day-5 biopsy did not show a statistically significant reduction. The findings do not establish that all biopsy procedures are risk-free.

Is day-5 embryo biopsy safer than day-3 biopsy?

The study found different outcomes for the two techniques, with a significant reduction in live births following day-3 biopsy but no statistically significant difference following day-5 biopsy. This supports the use of blastocyst-stage trophectoderm biopsy when biopsy is indicated, but the study was not a direct randomised comparison of the two approaches.

Does PGT-A increase the chance of having a baby?

Not necessarily for every patient. PGT-A provides information about chromosome-number abnormalities in sampled cells and may help with embryo selection in selected circumstances. Whether it improves outcomes depends on the patient population and the outcome being measured. It should not be assumed to increase cumulative live birth rates for everyone.

Does a normal PGT-A result guarantee a successful pregnancy?

No. A result indicating a chromosomally normal embryo does not guarantee implantation, an ongoing pregnancy or a live birth. Other embryo, uterine and patient-related factors can influence IVF outcomes.

What is the difference between embryo biopsy and PGT-A?

Embryo biopsy is the procedure used to collect cells from an embryo. PGT-A is a genetic test that analyses sampled cells for chromosome-number abnormalities. The biopsy obtains the sample; the genetic test analyses it.

Can I have embryo biopsy or PGT-A as part of IVF in Egypt?

Availability depends on the clinic, laboratory and treatment plan. If you are considering IVF in Egypt, ask your fertility provider whether embryo biopsy and PGT-A are available, why they might be appropriate in your case and what additional costs may apply.

The Take-Home Message

The 2013 Scott et al. study provides an important insight into the potential effects of embryo biopsy.

Day-3 biopsy was associated with a significantly lower live birth rate per embryo transferred in the study, whereas day-5 trophectoderm biopsy showed no statistically significant reduction. The latter finding is reassuring, but it does not prove that day-5 biopsy carries no risk.

Just as importantly, the effect of embryo biopsy and the effectiveness of PGT-A are separate questions. Understanding both is essential when deciding whether genetic testing should form part of an IVF treatment plan.

At Pyramedicine, we encourage patients to make fertility decisions based on individual circumstances, balanced evidence and clear discussions with their treating specialists.

Planning IVF treatment in Egypt? Contact Pyramedicine to discuss your options, ask questions about available fertility services and explore the practicalities of arranging treatment abroad.

Reference

Scott RT Jr et al. Fertility and Sterility. 2013. PMID: 23773313.