Preimplantation Genetic Diagnosis (PGD)

Preimplantation Genetic Diagnosis (PGD) is a crucial tool in in vitro fertilization (IVF) and surrogacy programs, enabling the detection of genetic and chromosomal abnormalities in embryos before they are implanted in the uterus.

Indications for PGD:

Age of the woman over 35 years: Increased risk of chromosomal abnormalities.
Recurrent miscarriage: Genetic abnormalities may be responsible for repeated miscarriages.
Multiple failed IVF attempts: PGD can help identify genetic causes of failure.
Genetic diseases in parents: Such as cystic fibrosis, sickle cell anemia, phenylketonuria.
Chromosomal abnormalities: For instance, translocations or inversions in the karyotype.
Mitochondrial disorders: Identifying embryos without mitochondrial DNA mutations.

PGD Process:

PGD is performed at the blastocyst stage when the embryo consists of 160–200 cells. The procedure involves a biopsy where 5–10 trophectoderm cells are extracted for genetic analysis. After the biopsy, the embryo is cryopreserved to prevent damage and allow time for the analysis.

Analysis Methods:

Various methods are used to detect genetic abnormalities:

FISH (Fluorescent In Situ Hybridization): Detects chromosomal abnormalities such as aneuploidy.
CGH (Comparative Genomic Hybridization): Used to analyze structural chromosomal changes.
PCR (Polymerase Chain Reaction): Identifies gene mutations related to hereditary diseases.
NGS (Next-Generation Sequencing): An innovative method that provides high accuracy in detecting chromosomal and genetic abnormalities.

PGD Results:

PGD results provide complete genetic information about each embryo. Based on this data, doctors decide on further treatment. If the embryo is free of genetic abnormalities, it is thawed and transferred to the uterus.

Benefits of PGD:

Increased IVF success: PGD allows the selection of only healthy embryos, increasing the chances of a successful pregnancy.
Reduced risk of miscarriage: Transferring embryos with a normal chromosomal structure reduces the risk of miscarriage.
Prevention of hereditary diseases: PGD helps prevent the transmission of serious genetic disorders to the child.

Research Insights:

According to the Journal of Assisted Reproduction and Genetics, over 75% of infertility clinics in the United States offer preimplantation genetic diagnosis (PGD), and approximately 4–6% of IVF procedures annually involve PGD. Modern technologies can successfully identify thousands of genetic defects, including cystic fibrosis, muscular dystrophy, sickle cell anemia, and rare diseases such as Denis-Drash syndrome and Hurler syndrome.

Research shows that the live birth rate after using PGD is about 37.8% in the first cycle and 67.6% after several cycles, comparable to natural conception. PGD also reduces the incidence of miscarriages and increases the likelihood of multiple pregnancies.

Diseases Detected by PGD:

PGD is recommended when there is an increased risk of transmitting certain genetic disorders or chromosomal abnormalities to offspring. Common indications for PGD include:

Known genetic diseases: Such as cystic fibrosis, sickle cell anemia, thalassemia, Huntington's disease.
Chromosomal abnormalities: Such as translocations or inversions, which can lead to miscarriages or birth defects.
Mitochondrial disorders: If parents carry mitochondrial DNA mutations, PGD helps identify embryos without these mutations.
Advanced maternal age: Women aged 35 and older have an increased risk of producing eggs with chromosomal abnormalities.
Recurrent miscarriage: PGD can identify embryos with chromosomal abnormalities that could cause repeated miscarriages.

Some couples may choose to use PGD not due to specific medical indications but to ensure the genetic health of their future chi