Preimplantation Genetic Testing (PGT): select healthy embryos before pregnancy
What is Preimplantation Genetic Testing (PGT)?
Preimplantation Genetic Testing (PGT) is an advanced technique that makes it possible to analyse the genetics of the embryos obtained through in vitro fertilisation (IVF) before they are transferred to the uterus.
Thanks to this study, it is possible to identify embryos without genetic abnormalities and increase the chances of achieving an ongoing pregnancy and a healthy baby.
PGT, formerly known as Preimplantation Genetic Diagnosis (PGD), is now a key tool in personalised reproductive medicine.
Sometimes it is not only about achieving pregnancy, but about doing so with greater confidence.
Types of Preimplantation Genetic Testing
PGT makes it possible to analyse different types of abnormality:
PGT-A (aneuploidies)
Detects abnormalities in the number of chromosomes.
It is particularly relevant in cases of advanced maternal age.
PGT-M (monogenic conditions)
Analyses hereditary conditions caused by the mutation of a specific gene.
PGT-SR (structural abnormalities)
Assesses changes in the structure of the chromosomes, such as losses or duplications of segments.
When is a PGT recommended?
Preimplantation Genetic Testing is indicated in different clinical situations:
Women of advanced maternal age (38+)
Recurrent miscarriage
Implantation failure
Couples with a history of genetic conditions
Karyotype abnormalities
Severe male factor
Previous pregnancies with chromosomal abnormalities
At Clínica Fertia we assess each case to determine whether PGT is the best option.
How is Preimplantation Genetic Testing carried out?
PGT forms part of an IVF treatment and follows these steps:
Normally, a single egg is produced in each natural cycle. Ovarian stimulation consists of administering hormones by subcutaneous injection in order to obtain more eggs. The whole process is monitored by ultrasound scans, for which we are available seven days a week. Depending on the type of protocol used and how quickly the ovary responds, the process will last between 10 and 12 days.
Once the follicles reach the appropriate number and size, a hormone called HCG is administered to complete the maturation of the eggs. Approximately 36 hours after the HCG is given, the mature eggs can be retrieved from the ovary.
It consists of the aspiration of the mature oocytes under ultrasound guidance and with light sedation, so that the patient does not feel any discomfort. The procedure lasts around 15 minutes. On that day we recommend not carrying out activities that require your full capacity, such as driving, even if you feel perfectly well.
Once the eggs have been obtained, they are inseminated with the previously processed semen in the laboratory. Sperm selection can be carried out using a technique known as MACS or by conventional capacitation methods such as concentration gradients, Swim Up, etc.
Fertilisation can be carried out by IVF or ICSI. In IVF, the biologist brings each oocyte into contact with the previously selected sperm and lets fertilisation take place on its own. In ICSI, by contrast, a single sperm is introduced into the egg with a very fine needle, around 15 microns in diameter. ICSI is used above all in severe sperm abnormalities, poor oocyte quality, valuable or scarce eggs, advanced maternal age, suspected low fertilisation rate, and cases with previous failure of conventional IVF.
When there is no sperm in the ejaculate (azoospermia) but there is in the testicle, a testicular biopsy (TESE) can be used. In this case the sperm are obtained from testicular tissue and cultured beforehand in the laboratory. The technique used in these cases will always be ICSI.
The embryos are cultured and observed in the laboratory for a few days (2 to 6). For this we have modern incubation techniques to monitor their development in real time (morphokinetics). We have incubators equipped with time-lapse technology, which incorporates an image capture system, allowing us to observe the embryos from fertilisation until the moment of transfer to the uterus, without having to remove them from the incubator. In this way the culture conditions are more stable, which means an improvement in embryo quality. This technology also makes it easier to select the best embryos to transfer and freeze.
The biopsy is carried out on day 5 or 6 of development, when the embryo has reached the blastocyst stage. At this stage the embryo has more than 100 cells and is divided into two parts. The cells are taken exclusively from the trophectoderm (the outer layer that will form the placenta), which ensures that the inner cell mass (which will form the baby) is not damaged in any way. A high-precision microscope and a laser are used to perform the biopsy: a small incision is made in the embryo’s outer shell (zona pellucida) and the selected cells are gently aspirated and sent for genetic analysis. After the biopsy, the embryos are vitrified.
It consists of the introduction of the embryos inside the uterine cavity. To do this, a speculum is placed in the vagina and a fine cannula carrying the embryos is introduced; the embryos are deposited in the uterus under ultrasound guidance. This process is quick and painless.
After the transfer we recommend relative rest that day and the following day, and then a return to your usual activity. We only recommend avoiding strenuous effort and sport for the following two weeks. Travelling poses no problem.
It is a process of cellular solidification at low temperatures (-196ºC) which are reached very rapidly, preventing the formation of crystals. Once vitrified, the eggs are stored inside straws using a closed system that prevents them from coming into contact with the liquid nitrogen in which they are immersed for preservation, thus guaranteeing the highest safety conditions.
This can be done by measuring BHCG in the blood 10 days after the embryo transfer.
Or by taking a urine test 14 days after the transfer.
Until confirmation, the medication prescribed on the day of the transfer must be continued.
Fifteen days after the BHCG test, an ultrasound scan is carried out to confirm embryo implantation; the gestational sac can be seen with the embryo inside it, and with a heartbeat present. Sometimes the heartbeat will be visible 7 days later.
How is Preimplantation Genetic Testing carried out?
PGT forms part of an IVF treatment and follows these steps:
Controlled ovarian stimulation
Egg retrieval
Fertilisation in the laboratory
Embryo culture until day 5 (blastocyst)
Embryo biopsy (cell removal)
Genetic analysis
Selection of healthy embryos
Embryo transfer
The biopsy is carried out at the blastocyst stage, when the embryo is sufficiently developed.
Does PGT harm the embryo?
The embryo biopsy procedure is a safe technique when carried out by a specialist team.
At Clínica Fertia we have an advanced laboratory and professionals with experience in highly complex techniques, which guarantees maximum precision and safety throughout the process.
Advantages of PGT in assisted reproduction
At our fertility clinic we work with a fully personalised approach:
- Increases the chances of an ongoing pregnancy
- Reduces the risk of miscarriage
- Makes it possible to avoid transmitting genetic conditions
- Improves embryo selection
- Reduces the number of attempts needed
Making informed decisions can completely change the path ahead.
Price of the Preimplantation Genetic Test
The cost of PGT may vary depending on:
- Type of test (PGT-A, PGT-M…)
- Number of embryos analysed
- Whether previous genetic studies are needed
At Clínica Fertia we work with personalised and transparent quotes, adapted to each case.
We recommend having an initial assessment in order to define the most appropriate treatment.
Preimplantation Genetic Testing at Clínica Fertia
At our fertility clinic we offer:
- Personalised genetic study
- Advanced assisted reproduction laboratory
- Team specialising in complex cases
- Support throughout the whole process
Our aim is to help you make decisions with confidence and increase your chances of success.
Frequently asked questions about Preimplantation Genetic Testing
Does PGT guarantee a pregnancy?
It does not guarantee pregnancy, but it does increase the chances by selecting genetically normal embryos.
How long does the PGT result take?
The genetic analysis usually takes between 7 and 15 days, depending on the laboratory and the type of study.
Is PGT necessary in all IVF treatments?
No. It is only recommended in specific cases such as advanced age, recurrent miscarriage or genetic conditions.
How many embryos can be analysed with PGT?
It depends on the number of embryos obtained in the IVF cycle. Each one can be analysed individually.
Can PGT be done with low ovarian reserve?
Yes, although it will depend on the number of embryos available. In some cases it is combined with strategies such as DuoStim.
Where can I have Preimplantation Genetic Testing in Málaga?
At Clínica Fertia we have advanced technology and experience in embryo genetic diagnosis.
If you are considering fertility treatment or want to know whether PGT is right for your case:
The first fertility appointment is free and includes a personalised medical assessment.