Preimplantation Genetic Testing (PGT)
WHAT IS PREIMPLANTATION GENETIC TESTING (PGT)
Preimplantation Genetic Testing (PGT) is an advanced laboratory technique used during IVF (In Vitro Fertilization) to analyze the genetic health of embryos before they are transferred into the uterus. It helps identify chromosomal abnormalities or inherited genetic disorders, ensuring that only healthy embryos are selected for implantation.
In simple terms, PGT allows doctors to check whether an embryo is genetically normal before pregnancy begins, thereby increasing the chances of a successful pregnancy and reducing the risk of miscarriage or genetic conditions in the baby.
At Freya Fertility, PGT is performed with high precision to improve IVF outcomes and support safer, healthier pregnancies.
PGT is beneficial for patients who:
- Have recurrent miscarriages
- Have repeated IVF failures
- Are above 35 years of age
- Have a family history of genetic disorders
- Have known chromosomal abnormalities
- Want to improve embryo selection and success rates
WHY PGT IS IMPORTANT
Not all embryos created during IVF are genetically normal. Some embryos may carry chromosomal abnormalities that can:
- Prevent implantation
- Lead to failed IVF cycles
- Cause early miscarriage
- Result in genetic disorders
PGT helps identify healthy embryos, allowing doctors to transfer the ones with the highest potential for a successful pregnancy.
TYPES OF PREIMPLANTATION GENETIC TESTING (PGT)
PGT is divided into three main types based on what kind of genetic abnormality is being tested. Each type serves a specific purpose and is recommended depending on the patient’s medical history.
PGT-A (Preimplantation Genetic Testing for Aneuploidy)
PGT-A is used to check whether an embryo has the correct number of chromosomes. A normal human embryo should have 46 chromosomes (23 pairs). If there are extra or missing chromosomes, it is called aneuploidy, which is one of the most common reasons for IVF failure and miscarriage.
What PGT-A detects:
- Extra chromosomes (e.g., Trisomy 21 – Down syndrome)
- Missing chromosomes (monosomy)
- Chromosomal imbalance affecting embryo viability
Why it is important:
- Helps select embryos with normal chromosomal count
- Reduces risk of miscarriage
- Improves implantation success
- Especially useful for women above 35 years
Who should consider PGT-A:
- Women with advanced maternal age
- Patients with repeated IVF failures
- Couples with recurrent pregnancy loss
- Cases of unexplained infertility
PGT-M (Preimplantation Genetic Testing for Monogenic Disorders)
PGT-M is used to detect specific inherited genetic diseases caused by mutations in a single gene. These conditions are passed from parents to children and may lead to serious health issues.
What PGT-M detects:
- Single-gene disorders such as:
- Thalassemia
- Cystic fibrosis
- Sickle cell anemia
- Muscular dystrophy
Why it is important:
- Prevents transmission of genetic diseases to the baby
- Ensures only unaffected embryos are selected
- Helps couples with known genetic conditions have healthy children
Who should consider PGT-M:
- Couples who are carriers of genetic disorders
- Families with a history of inherited diseases
- Patients with previously affected pregnancies
PGT-SR (Preimplantation Genetic Testing for Structural Rearrangements)
PGT-SR is used for couples where one partner has structural changes in chromosomes, such as translocations or inversions. These changes may not affect the parent but can lead to abnormal embryos.
What PGT-SR detects:
- Chromosomal translocations (exchange of chromosome segments)
- Inversions (reversed chromosome segments)
- Structural abnormalities affecting embryo development
Why it is important:
- Reduces risk of miscarriage
- Improves chances of healthy embryo development
- Helps achieve successful pregnancy in complex genetic cases
Who should consider PGT-SR:
- Couples with known chromosomal rearrangements
- Patients with recurrent miscarriages
- Cases of repeated IVF failure due to genetic factors
Initial Consultation & Genetic Assessment
The process begins with a detailed consultation where your fertility specialist reviews medical history, previous IVF cycles, and any known genetic conditions. Genetic counselling may be advised Blood tests or karyotyping may be done The appropriate type of PGT (PGT-A, PGT-M, or PGT-SR) is selected
Ovarian Stimulation
Hormonal medications are given to stimulate the ovaries to produce multiple eggs instead of the single egg in a natural cycle. Regular ultrasounds monitor follicle growth Hormone levels are tracked The goal is to retrieve multiple mature eggs
Egg Retrieval (Ovum Pick-Up)
Once follicles are ready, eggs are retrieved using a minimally invasive procedure: Performed under sedation A thin needle is guided through the vagina using ultrasound The procedure takes about 15–20 minutes
Fertilization (IVF / ICSI)
Retrieved eggs are fertilized with sperm in the laboratory. Usually, ICSI (Intracytoplasmic Sperm Injection) is preferred in PGT cycles A single sperm is injected into each egg This ensures better fertilization and prevents contamination of genetic material
Embryo Culture (Day 1–5/6 Development)
Fertilized eggs (embryos) are cultured in a controlled lab environment: Day 1–3: Early cell division stages Day 5–6: Embryos reach the blastocyst stage Only healthy, growing embryos are selected for testing
Embryo Biopsy (Key Step in PGT)
A small number of cells are carefully removed from the outer layer of the embryo (trophectoderm): Typically 5–10 cells are taken This part later forms the placenta (not the baby) The inner cell mass (future baby) remains untouched The procedure is performed using advanced micromanipulation tools 👉 This step is safe and does not harm embryo development when done by experts
Genetic Testing & Analysis
The biopsied cells are sent to a specialized genetics laboratory: DNA is extracted and analyzed Advanced technologies (like NGS – Next Generation Sequencing) are used Results determine whether the embryo is genetically normal or abnormal
Embryo Freezing (Vitrification)
After biopsy, embryos are frozen to preserve them while awaiting test results: Rapid freezing technique prevents damage Maintains high survival rates after thawing
Result Interpretation & Embryo Selection
Genetic reports categorize embryos as: Euploid (normal) – suitable for transfer Aneuploid (abnormal) – not recommended Mosaic (mixed) – may require specialist decision Doctors select the healthiest embryo for transfer.
Endometrial Preparation (FET Cycle)
The uterus is prepared for embryo transfer: Hormonal medications are given Endometrial thickness and receptivity are monitored Timing is synchronized with embryo development
Embryo Transfer (Frozen Embryo Transfer – FET)
The selected healthy embryo is transferred into the uterus: Simple and painless procedure No anesthesia required Takes only a few minutes
Luteal Support & Pregnancy Test
Hormonal support is continued after transfer Blood test is done after 10–14 days to confirm pregnancy
Follow-Up & Pregnancy Care
If pregnancy is confirmed: Regular monitoring is done Ultrasounds track fetal development Ongoing support ensures a healthy pregnancy
Freya Fertility
Our Success Highlights
Higher implantation rates with PGT-tested embryos
Reduction in miscarriage risk with genetic screening
Committed to Your Parenthood Journey
At Freya Fertility, we focus on improving both success and safety in fertility treatments. With PGT, we ensure better embryo selection, reduced risks, and higher chances of a healthy pregnancy.
FAQs
What is PGT in IVF?
It is a genetic test performed on embryos before transfer to detect abnormalities.
Is PGT safe for embryos?
Yes, it is a safe and widely used procedure when performed by experts.
Who should consider PGT?
Patients with genetic risks, repeated IVF failures, miscarriages, or advanced age.
Does PGT guarantee a healthy baby?
It reduces risks significantly but does not guarantee 100% outcomes.
Does PGT improve IVF success?
Yes, it improves implantation rates and reduces miscarriage chances.