PGT-A in Patients with Advanced Maternal Age – Success Stories

Posted in ,

Why Perform Preimplantation Genetic Diagnosis (PGD/PGT-A) in Spain?

Since its first application in humans in 1990, Preimplantation Genetic Diagnosis (PGD), also known as Preimplantation Genetic Testing (PGT), has been developed as an effective tool for selecting embryos based on their genetic makeup whilst excluding those with alterations linked to certain pathologies.

 However, despite its advantages, the application of PGD, as well as assisted reproductive treatments, is not carried out uniformly across all European countries. In most cases, legislation has not yet been adapted to the needs of society. This is why some countries, like Spain have become the most in-demand destinations for those seeking the help of PGD and, in general, assisted reproductive treatments. This is not only because Spain offers a favourable legal environment but also because of its high standards of healthcare, extensive experience, and high success rates.

What is Preimplantation Genetic Diagnosis (PGD-PGT)?

Preimplantation Genetic Diagnosis (PGD), or PGT, is a technique used in assisted reproduction that allows for the detection of genetic abnormalities in embryos before their implantation in the woman’s uterus. It is, therefore, a complementary technique that helps to choose the best embryo to transfer in an in vitro fertilization (IVF) treatment.

To do this, embryonic cells must be extracted at an early stage and then genetic analyses are conducted to identify any genetic or chromosomal disorders. This technique offers couples carrying serious genetic diseases the possibility of having a healthy child without transmitting these diseases to them.

It is possible to carry out three types of preimplantation genetic tests, depending on the patient:

  • PGT-A or aneuploidy screening: to detect chromosomal losses or gains in embryos. This is the case with Down syndrome, where three chromosomes (trisomy of pair 21) are detected instead of two.
  • PGT-M or monogenic disease screening: helps to detect alterations in the DNA sequence of a gene, thus allowing the detection of genetic diseases. This type of test is generally used when there is a history of a previous disease or when it is known that both parents are carriers of the same disease, and there is a risk of having children affected by this disease.
  • PGT-SR: this type of preimplantation genetic test allows for the detection of structural chromosome anomalies, which can lead to a disease. This type of test is performed when there are translocations in the parents.
Dr Laura Miguel, Medical Director - Clinica Tambre

Dr Laura Garcia de Miguel, Medical Director, Clinica Tambre Madrid

Older patients

Preimplantation genetic diagnosis (PGT-A) is a crucial tool in modern reproductive medicine, especially for older patients seeking to have a healthy child. As women age, the quality and quantity of their eggs decrease, which increases the risk of chromosomal abnormalities in embryos. These abnormalities can result in implantation failure, miscarriage or genetic disease in the newborn. This is where PGT-A plays a vital role.

PGT-A allows doctors to test embryos created by in vitro fertilisation (IVF) before they are transferred to the uterus. During this process, a small number of cells are removed from the blastocyst stage embryo and their chromosomes are examined. This helps to identify embryos with the correct number of chromosomes (euploid), which have a greater chance of resulting in a successful pregnancy and the birth of a healthy baby.

“For older patients, PGT-A is especially important because the incidence of chromosomal abnormalities increases with maternal age. Women over 35 years of age have an increased risk of producing chromosomally altered eggs, which can lead to a number of complications. By selecting euploid embryos for transfer, PGT-A significantly improves implantation rates and reduces the risk of miscarriage, offering greater hope for couples wishing to start a family” says Dr Laura Garcia de Miguel, the Medical Director of Clinica Tambre Madrid.

In addition, PGT-A can decrease the number of IVF cycles needed to achieve a viable pregnancy, which is both emotionally and financially beneficial. This approach not only increases success rates, but also reduces the stress and anxiety associated with prolonged fertility treatments.

Legislation on PGD in Spain

The law on in vitro fertilization in Spain is one of the most comprehensive and advanced pieces of legislation in the European framework. Specifically, Law 14/2006 on assisted human reproduction techniques defines the rules to follow in this field and protects access to motherhood for all groups in society.

This same 2006 law on assisted reproduction established a clear legal framework for the practice of preimplantation genetic diagnosis (PGD) in Spain, ensuring the protection of patients’ rights and compliance with quality standards in assisted reproduction centers.

In Spain, Preimplantation Genetic Diagnosis (PGD) or Preimplantation Genetic Testing (PGT) is authorized to select embryos for therapeutic purposes, and not for personal purposes, such as the selection of the sex of the embryo. This means its use is approved to detect serious hereditary diseases, of early onset, and not susceptible to postnatal curative treatment according to current scientific knowledge.

PGD is also authorized for the detection of other alterations that could compromise the viability of the embryo and, consequently, lead to implantation failure.

Authorized Cases for PGD in Spain

PGD is authorized in Spain in a large number of cases:

  • Serious genetic diseases: PGD can be used to prevent the transmission of serious genetic diseases, such as cystic fibrosis, Duchenne muscular dystrophy, Huntington’s disease, among others. The National Commission on Assisted Human Reproduction (CNRHA) is the department responsible for approving the diseases that can be tested in embryos.
  • Chromosomal abnormalities: PGD allows for the identification and non-transfer of embryos with chromosomal abnormalities, such as trisomy 21 (Down syndrome), trisomy 18 (Edwards syndrome), and trisomy 13 (Patau syndrome), among others.
  • Recurrent miscarriages: In cases of recurrent miscarriages of unknown cause, PGD can be used to analyse embryos and exclude chromosomal abnormalities as a possible cause.
  • Implantation failures: PGD can be used to select healthy embryos and increase the chances of success in assisted reproduction treatments, avoiding implantation failures.

Restrictions on Preimplantation Genetic Tests in European Countries

Outside Spain, legal restrictions on PGT are stricter. Some countries completely prohibit this technique, such as Ireland, Switzerland, Italy, and Austria. Others, like Germany, limit its use to specific cases or impose strict regulations that make access difficult. In Germany, PGD is only permitted in cases where there is a proven risk of a serious hereditary disease. In addition to requiring approval from an ethics commission, PGD can only be performed in clinics with specific authorization. It should also be noted that embryo freezing, and egg donation are prohibited in Germany, which constitutes an obstacle to parenthood.

In France, the use of PGD is also restricted, as it requires a doctor to certify the high probability of having a child with an incurable genetic disease. Furthermore, the anomaly can only be tested if it has already been identified in one of the parents.

Why Choose Preimplantation Genetic Diagnosis in Spain?

There are numerous advantages to practicing PGD in Spain. In addition to the solid legal framework, at Tambre, we are specialists in advanced reproductive medicine, with over 40 years of experience in assisted reproduction, and we have a high quality medical infrastructure that allows us to guarantee optimal results and comprehensive care, as evidenced by our 81% success rate in preimplantation genetic tests, states the Medical Director of Clinica Tambre, Dr. Laura García de Miguel.

PGT-A is an essential tool for older patients seeking to have a healthy child. By allowing the selection of embryos with the correct number of chromosomes, PGT-A improves IVF success rates, reduces the risk of miscarriage and increases the likelihood of healthy births.

In addition to state-of-the-art technology, the most prestigious Spanish clinics pay special attention to foreign patients. That is why they have gynaecologists specialised in fertility who speak several languages, so that patients can communicate with their medical team in their mother tongue, making the process more comfortable and less stressful for those who come to Spain in search of a healthy and happy baby.

Embryologist at Clinica Tambre

PGT-A Case Studies

A Couple with a History of Recurrent Miscarriages

The couple had experienced multiple miscarriages and sought help to conceive a healthy child. After undergoing several diagnostic tests, it was discovered that the mother had a chromosomal abnormality that increased the risk of miscarriage. During the consultation, the specialist recommended undergoing an IVF cycle with PGT-A. Through genetic analysis of the embryos before uterine transfer, those without chromosomal abnormalities were identified. The couple achieved a successful pregnancy and ultimately, a healthy baby was born.

In this case, the mother had a balanced translocation. This occurs when there is an exchange of genetic material between two chromosomes, but the total amount of genetic material remains the same. That is, there is no net loss or gain of genetic material. However, the altered arrangement of chromosomes can interfere with normal embryonic development and increase the risk of miscarriage. For example, in a balanced translocation, part of one chromosome can attach to another unrelated chromosome. If this occurs in a critical region of the genome that affects early embryonic development, it can lead to recurrent miscarriage due to the embryo’s inability to develop properly. This was the case for this couple, who suffered recurrent miscarriages due to a balanced translocation which was discovered in the woman. Preimplantation genetic diagnosis with aneuploidy screening (PGT-A) was the treatment option to select embryos that did not carry the balanced translocation, thereby reducing the risk of miscarriage.

A Couple with a Family History of Hereditary Genetic Disease

The couple came to Tambre with a family history of a hereditary genetic disease and wanted to avoid passing it on to their offspring. After consulting with the specialist, they opted to undergo an IVF cycle with PGT-A to select embryos free of the specific genetic mutation. After transferring healthy embryos to the uterus, the woman achieved a successful pregnancy and gave birth to a baby free of the genetic disease.

The couple had a family history of cystic fibrosis, an autosomal recessive genetic disease that primarily affects the lungs and digestive system. In a couple where both are carriers of a gene mutation, there is a significant risk of passing cystic fibrosis to their offspring. During the IVF process, after the eggs are fertilized with sperm in the lab, a biopsy of the developing embryos’ cells is performed. The cells are analyzed to detect the presence of specific gene mutations causing cystic fibrosis and to evaluate their chromosomal status. Two embryos were obtained that did not carry the genetic mutation and had a normal number of chromosomes. These embryos were selected for transfer to the woman’s uterus. The selection of embryos significantly reduces the risk of the child inheriting the disease and increases the chances of a successful pregnancy and a healthy baby.

An Older Woman Seeking to Maximize the Chances of a Successful Pregnancy

The patient wanted to be a single mother. She came to the clinic seeking her first pregnancy at the age of 41. She decided to undergo fertility treatment due to her advanced age and decreased ovarian quality. It has been shown that a woman’s advanced age is associated with a higher risk of chromosomal abnormalities in foetuses, such as Down syndrome. To maximize the chances of a successful pregnancy and reduce the risk of age-related chromosomal abnormalities, her specialist recommended IVF with PGT-A. Chromosomally normal embryos were selected for transfer, resulting in a successful pregnancy and the birth of a healthy baby.

PGT-A has been demonstrated as an important tool for older women seeking to conceive through fertility treatments, as it helps select chromosomally normal embryos, reducing the risk of miscarriages, improving implantation and pregnancy rates, and decreasing the likelihood of chromosomal abnormalities in the foetus.

From the age of 35, the quality of a woman’s eggs tends to decline. This decrease in ovarian quality can lead to an increase in the incidence of chromosomal abnormalities in the eggs, such as trisomy 21 (Down syndrome) and other aneuploidies, which are common causes of miscarriages and difficulties in conceiving.