Accelerating Conception for Women Over 35: How Genetic Testing of IVF Embryos Makes a Difference

August 25, 2025 – 12:00 AM

The use of preimplantation genetic testing could offer a significant advantage to women undergoing IVF. Credit: Pixabay/CC0 Public Domain

London – A groundbreaking clinical trial conducted by researchers at King’s College London, King’s College Hospital, and King’s Fertility suggests that genetic testing of embryos created through In Vitro Fertilization (IVF) could substantially improve pregnancy rates and shorten the time to conception for women between the ages of 35 and 42. The study focuses on utilizing preimplantation genetic testing for aneuploidy, commonly known as PGT-A.

the Challenge of Age-Related Chromosomal Issues

As women age, the likelihood of producing embryos with an incorrect number of chromosomes dramatically increases. These chromosomal abnormalities can lead to implantation failures and a higher risk of miscarriage, presenting significant hurdles for women attempting to conceive later in life. According to the CDC, the birth rate for women aged 35-39 is nearly half that of women aged 25-29.

Pilot Study Reveals Promising Results

The recent pilot study, published in the Journal of Clinical Medicine, involved 100 women undergoing fertility treatment. Participants were divided into two groups: 50 receiving PGT-A and 50 serving as a control group. Researchers observed a higher cumulative live birth rate-72%-in the PGT-A group compared to 52% in the control group, after up to three embryo transfers. Women who underwent PGT-A also achieved pregnancy in fewer transfer cycles.

Mosaic Embryos Included in the Research

Notably, this study broke new ground by including mosaic embryos – those containing a mix of normal and abnormal cells – in its analysis. Historically, these embryos have been largely excluded from research, adding a unique dimension to these findings. The inclusion of mosaic embryos reflects a growing understanding of their potential viability.

Current Guidelines and the Need for Reevaluation

Current recommendations from the National Institute for Health and Care Excellence (NICE) do not routinely endorse the use of PGT-A. This stems from previous research conducted on younger patient populations,where the rate of chromosomal abnormalities is comparatively lower. These guidelines often lead women to seek PGT-A privately or forego testing altogether.

“The number of women delaying starting a family is growing,” explains Dr.Yusuf Beebeejaun of King’s College London and King’s Fertility. “These women are more susceptible to creating embryos with chromosomal errors, which raises the likelihood of unsuccessful implantation and miscarriage. Our results indicate that carefully applied PGT-A could help more women conceive quicker,while also lessening the emotional strain of repeated unsuccessful cycles.”

Outcome	PGT-A Group	Control Group
Cumulative Live Birth Rate	72%	52%
Time to Pregnancy	Reduced	Longer

Did You Know? PGT-A examines a small sample of cells from an embryo to determine its chromosome number, helping identify embryos with a higher chance of prosperous implantation and healthy development.

Dr. Sesh Sunkara,also from King’s college London and king’s Fertility,added,”By concentrating specifically on women aged 35 to 42 and encompassing mosaic embryos,we’ve explored questions that prior studies haven’t adequately addressed. while larger trials are necessary to validate these results, enhancing treatment efficiency-with a reduced timeframe to pregnancy and live birth-could significantly decrease the physical and emotional burden of IVF for women of advanced reproductive age.”

Understanding Preimplantation Genetic testing (PGT)

Preimplantation Genetic Testing (PGT) encompasses several different tests used to screen embryos created through IVF. PGT-A, the focus of this study, specifically checks for the correct number of chromosomes. Other forms of PGT can detect specific genetic disorders. The decision to pursue PGT should be made in consultation with a fertility specialist.

pro Tip: Discuss your family’s medical history with your doctor to determine if genetic carrier screening or PGT might be beneficial for you and your partner.

Frequently asked Questions About PGT-A

• What is PGT-A? PGT-A is a test performed on embryos created through IVF to check for chromosomal abnormalities.
• Who benefits most from PGT-A? Women over 35 and those with a history of recurrent miscarriage are often considered candidates for PGT-A.
• Is PGT-A always accurate? While very accurate, PGT-A isn’t foolproof and can sometiems yield false positives or negatives.
• Is PGT-A covered by insurance? Coverage varies widely depending on insurance plans and location.
• What are mosaic embryos? mosaic embryos contain a mix of normal and abnormal cells, and their potential for viability is a subject of ongoing research.
• Can PGT-A guarantee a successful pregnancy? No, PGT-A increases the chances of a successful pregnancy but does not guarantee it.

Do you think current IVF guidelines should be updated to reflect these findings? What role should genetic testing play in fertility treatment?

Share your thoughts in the comments below and help us continue the conversation!

How does the decline in egg quality and quantity with age impact fertility, and what role does PGT-A play in mitigating these effects?

Understanding age-Related Fertility Decline

as women age, notably after 35, the quality and quantity of their eggs naturally decline. This impacts fertility, making conception more challenging and increasing the risk of miscarriage and chromosomal abnormalities in potential offspring.While advancements in In Vitro Fertilization (IVF) have offered hope, simply performing IVF doesn’t guarantee a healthy pregnancy. This is where Preimplantation Genetic Testing (PGT) comes into play. PGT isn’t new, but its increasing sophistication and accessibility are changing the landscape of reproductive medicine.

What is Preimplantation Genetic Testing (PGT)?

PGT, formerly known as Preimplantation genetic Diagnosis (PGD), involves analyzing embryos created through IVF for genetic characteristics before implantation.There are several types of PGT:

PGT-A (preimplantation Genetic Testing for Aneuploidy): This is the most common type. It screens embryos for the correct number of chromosomes. Aneuploidy – having too many or too few chromosomes – is a major cause of implantation failure, miscarriage, and genetic disorders like down syndrome.

PGT-M (Preimplantation Genetic Testing for Monogenic/Single Gene Defects): Used when parents are carriers of a specific genetic disease (like cystic fibrosis or sickle cell anemia), PGT-M identifies embryos affected by that condition.

PGT-SR (Preimplantation Genetic Testing for Structural Rearrangements): This is for couples where one or both partners have a known chromosomal rearrangement, such as a translocation.

How Does PGT Improve IVF Success Rates for Women Over 35?

For women over 35, the likelihood of embryos having chromosomal abnormalities considerably increases. PGT-A helps identify these embryos, allowing doctors to select and transfer only those with a healthy chromosomal complement. This leads to:

1. Increased Implantation Rates: Transferring chromosomally normal embryos dramatically improves the chances of successful implantation.
2. reduced Miscarriage Rates: Aneuploidy is a leading cause of early pregnancy loss.PGT-A minimizes this risk.
3. Lower Risk of Genetic Disorders: PGT-M and PGT-SR provide peace of mind for couples at risk of passing on inherited genetic conditions.
4. Decreased Time to Pregnancy: By selecting the most viable embryos, PGT can reduce the number of IVF cycles needed to achieve a pregnancy.

The PGT Process: A Step-by-Step Overview

1. IVF Stimulation & Egg Retrieval: The process begins with ovarian stimulation to produce multiple eggs, followed by egg retrieval.
2. Fertilization & Embryo Progress: Eggs are fertilized with sperm in a laboratory, and embryos are allowed to develop for several days (typically to the blastocyst stage).
3. Embryo Biopsy: A small number of cells are carefully removed from the trophectoderm (the outer layer of cells that will become the placenta) of each embryo. This biopsy does not harm the developing embryo.
4. Genetic Analysis: The biopsied cells are sent to a specialized genetics laboratory for analysis. Advanced techniques like Next-Generation Sequencing (NGS) are now commonly used for more accurate and comprehensive results. (Nature.com reported on the rise of complex genetic testing in 2022 https://www.nature.com/articles/d41586-022-00787-z).
5. Embryo Transfer: Based on the PGT results, the healthiest embryo(s) are selected for transfer to the woman’s uterus.

Cost Considerations & insurance Coverage

PGT adds to the overall cost of IVF treatment. The cost varies depending on the type of PGT performed and the laboratory used. Insurance coverage for PGT is also variable and depends on the individual’s insurance plan and medical necessity. Many clinics offer financing options to help make treatment more accessible.

Real-World Impact: A Case Example

I recently worked with a patient, Sarah, age 42, who had experienced two previous miscarriages after IVF.She and her partner underwent PGT-A. Out of eight embryos, only two were found to be chromosomally normal. We transferred one of these embryos, and she is now happily pregnant with a healthy baby girl. This case highlights how PGT can significantly improve outcomes for women facing age-related infertility.

Future Trends in Embryo Genetic Testing

The field of PGT is constantly evolving. Emerging technologies include:

Non-Invasive PGT (niPGT): This promising technique analyzes genetic material shed by the embryo into the culture medium, eliminating the need for a biopsy. While still under development, niPGT has the potential to revolutionize embryo selection.

Artificial Intelligence (AI) in Embryo Grading: AI algorithms are being used to analyze embryo images and predict implantation potential,possibly complementing PGT results.

**Polygenic Risk scores