For many women, the decision to try for a child later in life is made with clarity and confidence. Careers are established, lives feel settled, and the timing finally feels right. What often comes as a surprise is how quietly age influences fertility outcomes, shaping IVF success long before pregnancy can begin.
After the age of 35, one of the most significant factors affecting conception is not always visible during routine evaluations. It lies within the chromosomes of the embryos themselves, influencing whether implantation succeeds, a pregnancy progresses, or repeated disappointment follows.
What age does to embryos
Human eggs are present from birth. Over time, these eggs accumulate the effects of ageing at a cellular level. As maternal age increases, the mechanisms responsible for accurate chromosomal division during fertilisation become less reliable. The result is a higher proportion of embryos with an abnormal number of chromosomes, a condition known as aneuploidy.
For women under 35, the proportion of chromosomally abnormal embryos in a given IVF cycle is estimated at approximately 46%. By the late thirties and early forties, that figure rises to over 60%. Many of these embryos fertilise normally and reach the blastocyst stage. Some may even implant. However, they carry a significantly higher risk of implantation failure, early pregnancy loss, or chromosomal conditions.
Crucially, these abnormalities cannot be identified by appearance alone. An embryo that looks healthy under the microscope may still carry chromosomal errors that prevent a successful pregnancy. This is why repeated IVF failure, when no other medical explanation is evident, often traces back to chromosomal issues.
Seeing what morphology cannot
This is where preimplantation genetic testing changes clinical decision making. While embryo morphology offers valuable insights into development and quality, it provides no information about chromosomal health. PGT A adds that missing layer.
Preimplantation Genetic Testing for Aneuploidies involves taking a small biopsy from each embryo at the blastocyst stage, typically on Day 5 or Day 6 of development. These cells are analysed using Next Generation Sequencing, producing a detailed chromosomal profile. Each embryo is classified as euploid, aneuploid, or mosaic.
The testing does not alter or damage embryos. What it changes is the precision of embryo selection. Instead of relying solely on appearance, clinicians can identify which embryo has the highest likelihood of leading to a healthy ongoing pregnancy.
There is a common misconception that genetic testing in IVF is only relevant for couples with a known family history of inherited conditions. PGT A addresses a different challenge. It focuses on age related chromosomal errors that affect all women, regardless of health or genetics.
A case that explains the outcome
At Birla Fertility & IVF, a 37-year-old woman with primary infertility, bilateral PCOS, and a history of multiple IUIs, including one that ended in a missed abortion, sought treatment after two unsuccessful IVF cycles. One cycle produced no embryos suitable for transfer. The second resulted in a frozen embryo transfer that did not lead to pregnancy. Standard evaluations failed to identify a clear cause.
Given her age, pregnancy history, and pattern of implantation failure, the clinical team recommended another IVF cycle using ICSI along with PGT A. Individualised ovarian stimulation resulted in five good quality blastocysts.
Chromosomal testing revealed that only two of the five embryos were euploid. The remaining three were chromosomally abnormal, despite appearing suitable based on morphology alone.
A single euploid embryo was selected for frozen embryo transfer. The pregnancy progressed smoothly, and the couple welcomed a healthy baby boy.
PGT A provided the missing insight that had not been visible across earlier cycles. Identifying the right embryo made a meaningful difference, both clinically and in the patient journey.
Precision as clinical practice
As fertility care in India continues to evolve, patients are asking sharper questions and seeking clearer answers. PGT A represents a meaningful shift from probability to precision in IVF treatment.
At Birla Fertility & IVF, PGT A is offered as part of a personalised, evidence-based approach to care. For women planning pregnancy in their thirties, and for couples with prior IVF failure, it provides something essential: clarity rooted in science, and a more informed path forward.
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