Choosing the Best Embryo: How Genetics Shapes IVF Success
By Dr. Jyothi C. Budi, Medical Director, Ferty9 Fertility Center
For couples going through IVF, the journey is often filled with both hope and uncertainty. Each cycle represents months of preparation, medical care, and emotional strength. At the heart of this journey lies an important decision: which embryo to transfer. In recent years, science has given us new tools to make this choice more accurate and more reassuring.
Earlier, embryos were chosen based only on how they looked under the microscope. While appearance gives some clues, it cannot reveal the full story. Advances in genetics now allow us to identify genetically normal embryos, increasing the chances of implantation.
Every embryo carries chromosomes, the genetic material that determines whether it can develop normally. A normal embryo has 46 chromosomes, half from the mother and half from the father. This is called a euploid embryo. If chromosomes are missing or extra, the embryo is aneuploid. Such embryos are less likely to implant and more likely to result in miscarriage. Preimplantation genetic testing for aneuploidy, or PGT-A, helps detect these chromosomal abnormalities before transfer.
In addition, preimplantation genetic testing for monogenic disorders (PGT-M) allows couples to screen embryos for specific inherited conditions such as thalassemia, cystic fibrosis, or spinal muscular atrophy. This test is particularly valuable for families with known genetic risks, as it allows them to select embryos free from these disorders and significantly reduces the chance of passing on serious conditions.
Another important test is preimplantation genetic testing for structural rearrangements (PGT-SR). This checks if an embryo has changes in the structure of its chromosomes, called translocations or rearrangements, which can cause repeated IVF failure or miscarriage. PGT-SR is especially helpful for couples where one partner carries such chromosomal changes or for those who have faced multiple pregnancy losses.
Indian research shows that even embryos that look healthy under the microscope may carry hidden genetic problems. Women with repeated IVF failures or advanced maternal age benefit from genetic testing, as it improves the likelihood of a successful pregnancy while reducing emotional and financial strain.
It is important to remember that genetics is only one factor in IVF success. Uterine health, hormone balance, and sperm quality are equally important. Genetic testing adds cost and time, so it is usually recommended for women above 35, couples with multiple failed IVF attempts, recurrent miscarriage, or known genetic risks.
Genetic testing has transformed embryo selection from guesswork into an informed decision. By combining genetic insights with overall fertility health, doctors can guide couples toward better outcomes. For many it has provided clarity, confidence, and hope, helping them move closer to the dream of holding a healthy baby in their arms.
