Embryo biopsy is the procedure by which one or more cells are removed from an embryo in order to analyze its DNA and look for any genetic alteration.
This technique is performed during an in vitro fertilization (IVF) treatment, when the embryos are at day 3 or 5 of development, for preimplantation genetic diagnosis (PGD). However, it is most common to biopsy embryos at the blastocyst stage or day 5 of development due to its advantages.
The results of the genetic analysis after the embryo biopsy take a few days. Therefore, it will be necessary to vitrify the blastocysts and wait for the next cycle for delayed transfer.
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Definition of embryo biopsy
The goal of assisted reproductive techniques is to achieve a pregnancy and a healthy baby at home. If the embryos are genetically altered, they will have more difficulty implanting and/or miscarriage will occur.
Embryo biopsy is a complementary technique performed after in vitro fertilization (IVF) treatment. Thanks to this technique and its subsequent genetic analysis, it is possible to know the chromosomal information of the embryos obtained in the laboratory.
There are two times during embryo culture at which embryo biopsy can be performed: day 3 and day 5 of development. A few years ago, the trend was to biopsy embryos at day 3. However, nowadays, the most common procedure is to perform the embryo biopsy at the blastocyst stage.
Benefits of biopsy on day 5
Embryo biopsy at day 5 of development or blastocyst stage offers several advantages over biopsying embryos at day 3. Some of them are listed below:
- Lower economic investment. Not all embryos that reach day 3 of development will be able to reach blastocyst stage. Therefore, the number of blastocysts to be biopsied is usually lower than that obtained on day 3.
- Reduction of erroneous results due to a lower risk of mosaicism in blastocysts.
- Increased lik elihood that the blastocysts will be genetically healthy.
- Diagnostic accuracy since the number of cells analyzed in blastocyst biopsy is higher compared to embryo biopsy on day 3.
To perform a PGD, one should undergo IVF as the main treatment. If you are looking for a clinic to get started, we recommend that you generate your individual Fertility Report now. It is a useful, simple tool that, in just 3 steps, will give you a list of the clinics that have passed our rigorous selection process. You will receive an email in your inbox with a report that contains tips and recommendations to get started.
Ultimately, blastocyst biopsy has numerous benefits and will help increase implantation and pregnancy rates. In addition, embryo biopsy results are crucial for decision making.
Embryo biopsy procedure
The key to biopsy an embryo is to take a sample of cells without harming the development and evolution of the embryo. The embryo biopsy process is quite safe and does not compromise embryo survival. However, not all embryos are amenable to biopsy. In addition, it is important that qualified and specialized personnel perform the embryo biopsy, as it requires great skill.
The first step for embryo biopsy is the observation of the embryos under the microscope. A hole is then made in the zona pellucida of the embryo by laser or with a microneedle. Once the incision is made in the pellucid zone of the embryo, several cells of the trophoectoderm are extracted by aspiration.
These cells extracted from the embryo are placed in a tube and sent to the corresponding laboratory for genetic analysis by polymerase chain reaction (PCR) or microarrays, for example. The biopsied blastocysts are vitrified at -160ºC while awaiting the results.
Embryo biopsy results
When the responsible center receives the results of the embryo biopsy, it will inform the patient.
An embryo is considered genetically normal or euploid when its chromosomal content is correct. These embryos are more likely to implant and result in pregnancy. However, the transfer of euploid embryos does not necessarily mean pregnancy, as it will also depend on other factors. In contrast, embryos with chromosomal abnormalities are considered aneuploid and are discarded. In addition, there may be uninformative embryos or mosaic embryos.
In the event that no healthy or euploid embryos were obtained, a repeat IVF cycle with PGD would have to be performed. Another alternative would be to resort to gamete donation. We recommend you visit the following article for more detailed information: Pregnancy probability with preimplantation genetic testing.
FAQs from users
Can all diseases be diagnosed with embryo biopsy?
Embryo biopsy provides information about chromosomal endowment or the presence of certain mutations (alterations in genes). This allows us to diagnose chromosomally based diseases early, and some genetically based diseases (those known and legally approved).
However, this technique does not allow the diagnosis of all diseases. Therefore, it is very important to carry out a correct perinatal control of the gestation and of the children born in order to diagnose other types of diseases at an early stage.
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Is PGD biopsy possible on embryos that have been previously vitrified?
Yes, it is possible. However, ideally, the embryos should be biopsied fresh and the transfer should be deferred.
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What is the price of embryo biopsy?
When an embryo biopsy is performed, it is because a genetic study of the embryos is going to be carried out. Therefore, the cost will be that of an in vitro fertilization (IVF) with preimplantation genetic diagnosis (PGD), that is, around 8,000-9,000 euros approximately.
However, there may be variations in the price of IVF with PGD depending on the number of embryos to be analyzed.
Can embryo biopsy cause abnormalities in the embryo?
Since this is a very early stage of embryonic development, the embryo will compensate for the absence of the extracted cell and continue to multiply naturally. Therefore, performing PGD on the embryo does not imply any alteration in its genetic endowment.
However, this technique involves the manipulation of the embryo, which may affect its ability to evolve. This is the reason why PGD is generally recommended only in the necessary cases and not in a generalized way.
Suggested for you
If you want to know all the complete information about the PGD process, you can visit this article: What is the preimplantation genetic diagnosis procedure?
If you are interested in knowing the diseases that can be detected with PGD, then we invite you to click here: What genetic or chromosomal diseases can PGD detect?
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References
Alessandra Alteri, Greta Chiara Cermisoni, Mirko Pozzoni, Gerarda Gaeta, Paolo Ivo Cavoretto, Paola Viganò. Obstetric, neonatal, and child health outcomes following embryo biopsy for preimplantation genetic testing. Hum Reprod Update. 2023 May 2;29(3):291-306. doi: 10.1093/humupd/dmad001 (View)
Cynthia K Sites, Sophia Bachilova, Daksha Gopal, Howard J Cabral, Charles C Coddington, Judy E Stern. Embryo biopsy and maternal and neonatal outcomes following cryopreserved-thawed single embryo transfer. Am J Obstet Gynecol. 2021 Sep;225(3):285.e1-285.e7 (View)
Danilo Cimadomo, Antonio Capalbo, Filippo Maria Ubaldi, Catello Scarica, Antonio Palagiano, Rita Canipari, Laura Rienzi. The Impact of Biopsy on Human Embryo Developmental Potential during Preimplantation Genetic Diagnosis. Biomed Res Int. 2016:2016:7193075. doi: 10.1155/2016/7193075. Epub 2016 Jan 28 (View)
Rafael Sellers, Juan Carlos Castillo, Jorge Ten, Adoración Rodríguez, José A Ortiz, Francisco Sellers, Joaquín Llácer, Rafael Bernabeu. Monozygotic twinning following embryo biopsy at the blastocyst stage. JBRA Assist Reprod. 2021 Feb 2;25(1):122-127. doi: 10.5935/1518-0557.20200069 (View)
Tijana Vlajkovic, Mihaela Grigore, Rik van Eekelen, Lucian Puscasiu. Day 5 versus day 3 embryo biopsy for preimplantation genetic testing for monogenic/single gene defects. Cochrane Database Syst Rev. 2022 Nov 24;11(11):CD013233 (View)
FAQs from users: 'Can all diseases be diagnosed with embryo biopsy?', 'Is PGD biopsy possible on embryos that have been previously vitrified?', 'What is the price of embryo biopsy?' and 'Can embryo biopsy cause abnormalities in the embryo?'.
