The pre-implantation genetic diagnosis offers the possibility of analysing the presence of chromosomal and genetic anomalies in embryos before transferring them to uterus, previous to implantation.

As previously mentioned, the couple must be treated to obtain the most trustworthy result using PGD. Under these conditions, after fertilisation, the human zygote begins dividing every 24 hours. Three days after obtaining the ovules, the embryo consists of approximately 8 cells or blastomeres. At this time, the embryo biopsy is performed, which is a technique that extracts 1 or 2 blastomeres to be analysed. The embryo is kept in a culture until the biopsy results have been achieved and it is then transferred.

These chromosomal or genetic analysis techniques allow a very rapid diagnosis ranging from 3 to 48 hours, depending on the case. This is compatible with the maximum time of embryo development in vitro. This way, we can keep the embryos in a culture medium until the results are achieved and select the normal embryos to be transferred to the womb.

Through PGD, chromosomal and genetic anomalies are detected very early on, before implantation. This provides a great advantage when compared to prenatal diagnosis techniques (amniocentesis and chorionic villous biopsy) which give the option of abortion or therapeutic abortion when fetal abnormalities are detected.

Advice to use a PGD

• Couples at risk of transmitting chromosomal alterations or monogenic diseases.
• Couples with history of recurrent abortions.
• Implantation failure after multiple attempts.
• Alterations in meiosis or sperm. Older women.