The main assisted reproduction techniques
PGD (Preimplantation Genetic Diagnosis) is one of the techniques included in our Pregnancy Guarantee Programmes. It enables us to find or rule out genetic defects in embryos, so that only healthy ones are transferred.
To learn more about PGD, we went to the laboratory at Ovoclinic Madrid to talk to Rubén Dasi, embryologist and expert in this procedure.
THANKS TO THE CONTINUOUS ADVANCES IN THE FIELD OF ASSISTED REPRODUCTION, VARIOUS TECHNIQUES ARE CURRENTLY BEING USED TO OBTAIN GENETICALLY NORMAL EMBRYOS AND, CONSEQUENTLY, BETTER RESULTS.
HOW WOULD YOU DEFINE PRE-IMPLANTATION GENETIC DIAGNOSIS?
Preimplantation Genetic Diagnosis is a series of techniques that enable us to accurately detect genetic abnormalities in embryos from an IVF (In Vitro Fertilisation) cycle.
By performing PGD, we can obtain embryos that do not have a specific disease (PGT-M), structural rearrangements (PGT-SR), and / or abnormalities in the number of chromosomes (PGT-A). It therefore helps to increase the chances of embryo implantation and, consequently, pregnancy success rates.
HOW IS A PGD PERFORMED, AND WHAT ADVANTAGES DOES IT PROVIDE?
In order to carry out a genetic analysis of embryos in an IVF process, a biopsy must be performed to analyse the cells from the trophectoderm of a blastocyst on day 5/6 of development. Once the results have been obtained, the embryo that will lead to the birth of a healthy baby can be transferred to the recipient’s uterus.
IVF / ICSI IS ONE OF THE MOST COMMMONLY REQUESTED LABORATORY PROCEDURES.
IS IT ADVISABLE TO CARRY OUT IVF WITHOUT PERFORMING A PGD ON THE EMBRYOS OBTAINED?
With age, gamete quality decreases, and the probabilities of the embryo having genetic abnormalities increase. Consequently, if there are no other indications, PGD is recommended to achieve a successful pregnancy with the smallest number of cycles.
WHAT IS THE DIFFERENCE BETWEEN EMBRYOS WITH CHROMOSOMAL ALTERATIONS AND MOSAIC EMBRYOS?
An aneuploid embryo has chromosomal alterations in all of its cells, whereas in a mosaic embryo, there are two or more cells with different chromosomes. Mosaic embryos are categorised by how many chromosomes are impacted, whether it affects all or just a portion of the chromosome, and the level of mosaicism detected.
ONCE THE BIOPSY HAS BEEN PERFORMED AND THE HEALTHY EMBRYOS SELECTED, CAN THEY BE VITRIFIED UNTIL THE DAY OF TRANSFER WITHOUT AFFECTING THE QUALITY?
After the biopsy, the embryos are vitrified while waiting for the results. On the day of transfer, the embryos that are suitable for thawing are selected. The quality of the embryos is the same as when they were vitrified, and the biopsy procedure should not affect the viability of the embryos, as long as the qualified personnel have the right experience and the embryo is of high quality.
APART FROM DGP, WHAT OTHER LABORATORY TECHNIQUES OR PROCEDURES HELP US TO TRANSFER HEALTHY EMBRYOS?
There are complementary screening techniques such as FISH analysis in sperm, genetic carrier testing in both parents, etc. The results of these techniques give us information about the gametes and help us to develop the most appropriate strategy for IVF. However, PGD is the technique of choice because it allows us to determine precisely whether or not the embryo we are transferring has the correct chromosomal makeup.
If you have more questions about DGP or other IVF doubts, don’t hesitate to write to us at: firstname.lastname@example.org and we will help you to solve them. The first visit is free of charge.