A large number of IVF failures are blamed on poor embryo quality and fertility experts recommend Pre-implantation genetic testing (PGT) to select the best embryo that is most likely to result in a positive pregnancy. So, can you improve your IVF success with PGT?

Yes, IVF success rates are improved with PGT but the benefit is more for certain groups of people as we discuss below.

What is the success rate of IVF with PGT-tested normal embryo?

Some of our top doctors for IVF in Malaysia have demonstrated average IVF success rates of upto 82.9% with the transfer of a single, genetically-tested, good-graded euploid embryo.

How does PGT improve IVF success rates?

Using PGS, the embryos can be checked for abnormal chromosome number (aneuploidy), which is a major cause of both implantation failure and miscarriage. This allows the doctor to transfer only healthy embryos into the uterus, thus improving the chances of IVF success.

Can you increase your IVF success with PGT

PGS is also known as pre-implantation genetic testing for an aneuploidy (PGT-A).

What percentage of embryos pass PGT testing?

Chromosomal abnormalities in embryos are common. In fact, according to a study published in Biomed Central (1), nearly 50% of all IVF embryos are actually aneuploid.

Dr. Tan, from one of Asia’s top IVF clinics for genetic testing, explains in the below video how PGT helps improve IVF success:

When is genetic testing of embryos recommended?

There are certain scenarios in which the chances of having abnormal chromosome number are higher. For this reason, there are some patient groups who may stand to benefit from PGT more than others:

  • If one or both partners are carriers of a genetic disorder, PGD will be recommended
  • Women who have had several failed fertility treatments
  • Women who have experienced recurrent miscarriages, including ‘chemical’ pregnancies.
  • Women who are over the age of 35 and hence at a greater risk for aneuploidy

Recurrent miscarriages and failed IVF cycles can be the result of aneuploid embryos. The incidence of chromosomal abnormalities and consequent fertility problems increases with advancing maternal age, and by employing PGT technology, the transfer of aneuploid embryos can be avoided.

With the transfer of healthier embryos to the uterus, you have better chances of IVF success.

Can PGT increase the rate of clinical pregnancy?

The implantation rate after PGT is higher as is the rate of clinical pregnancy.

Data published by Dr. Colin Lee (one of the most successful doctors for PGT) and colleagues in Reproductive Biomedicine Online, in 2016, shows:

  • There is much better chance of IVF success with PGT testing in women who were over the age of 35. The largest increase in rates occurred in women aged between 38 and 41.
  • PGT had very little impact on the rate of pregnancy in women below 35.

Taking into account the effects of increasing age on fertility, these results are not surprising. They suggest that women in their late 30s are more likely to benefit from PGT.

To add weight to this data, another study published in Fertility and Sterility (3), in 2013 found that:

If a chromosomally normal embryo is transferred into an older woman, the chances of successful implantation and pregnancy are not significantly different to that of a younger woman.

Additional studies and data from fertility clinics also support these findings. As an example, the Biomed Central study mentioned above states that IVF success rate with PGT tested embryos was 69.1 percent as compared to 41.7 percent in cases where the embryos were selected simply based on their morphology.

Embryos that look healthy on examination under the microscope can still have potential problems that may affect successful implantation and pregnancy.

IVF success rates with PGT normal embryos are significantly higher than those with non-genetically-tested embryos.

What are the other benefits of PGT in IVF?

Besides enhancing the rates of successful clinical pregnancies from IVF, genetic testing also has several other benefits as:

  • Reduced risk of miscarriage:
    Single miscarriages are relatively common, with 1 in 4 pregnancies ending this way. Multiple miscarriages however are less common and can be caused by chromosomal abnormalities. Therefore, choosing only the healthiest embryos for transfer may help to prevent this. Despite there being limited data available, a systematic review (4) published in Fertility and Sterility in 2011, describes a marked decrease in miscarriage rate from 28% in the natural conception group, to 9% in the PGS group.
  • Reduced risk of multiple pregnancies:
    Since PGT tested embryos have better success rates, the doctors don’t need to take their chances with multiple embryo transfers, which may result in dangerous outcomes for both the mother and the baby. 
  • Speed up successful IVF process:
    PGT may shorten the length of time needed to achieve a successful pregnancy. This can be a particularly important factor, given how emotionally and financially draining the process of IVF treatment can be.
  • Reduced financial burden: Even though PGT is an added expense in your IVF treatment, it can actually save you money by helping achieve the pregnancy without wasting extra money for subsequent frozen embryo transfers or repeat cycles.

How accurate is PGT testing for Down syndrome?

PGT is highly accurate in preventing diseases like Down’s syndrome but there can be false-reports as there are some limitations to the technology as listed below.

Limitations of PGS testing in IVF

Given that only about 70% of PGT embryos lead to a healthy pregnancy, there must be some limitations to the genetic testing procedure.

These include:

  • Limited sample size: Only a few cells from the outer section are removed for PGS analysis, leaving intact the inner cells that will actually give rise to the baby. It was believed that the limited sample may not accurately represent all cells within the embryo. However, scientific research has shown that the outer portion of the embryos is similar to the inner and there is a significant connection between the two. Therefore, the biopsy sample taken is representative of the entire embryo.
  • Mosaicism: Mosaic embryos have both normal and abnormal cells. If the number of abnormal cells is small, these embryos may still be healthy and their use may or may not result in a healthy pregnancy.
  • Invasive procedure: There were concerns regarding possible damage to the embryo by taking cells from it at such an early stage of development, so the doctors advise against biopsy on Day 3. Performing the biopsy at day-5 blastocyst stage keeps embryo viability intact.
  • No viable embryos in the cycle: Women of advanced age sometimes have very few embryos in an IVF cycle, and PGT may find that none of them are viable. Even though it is better than having a chromosomally abnormal (aneuploid) embryo transferred but to the patient it may feel like a wasted cycle without any transfers.

Do you need Genetic Testing with IVF?

PGT-A is usually recommended by fertility doctors to the patient groups described above; it is not for everyone.

A different kind of technology, PGT-M is used for detection of genetic diseases.

If there is an indication of the possibility of having chromosomal abnormalities in your situation, the doctor/embryologist will guide you regarding PGT-A.

Studies and clinical data show an increase in pregnancy rates when genetic testing is combined with IVF. As shown in the data from Reproductive Biomedicine Online presented above, this increase can be as much as 30 percent.

To learn if you can increase your IVF success with PGT and find the most affordable IVF-PGT treatments, get in touch using the red contact button on this page.
References
  1. Yang, Z., Liu, J., Collins, G.S. et al. Selection of single blastocysts for fresh transfer via standard morphology assessment alone and with array CGH for good prognosis IVF patients: results from a randomized pilot study. Mol Cytogenet 5, 24 (2012). https://doi.org/10.1186/1755-8166-5-24
  2. Sin Yee Low, Colin Soon Soo Lee, Yun Xin Lim, Euploid blastocysts show a trend of higher implantation and
    clinical pregnancy rates compared to untested blastocysts in
    FET cycles https://www.rbmojournal.com/article/S1472-6483(16)30179-1/pdf
  3. Fertility and Sterility® Vol. 100, No. 6, December 2013 0015-0282/$36.00
    Copyright ©2013 American Society for Reproductive Medicine, Published by Elsevier Inc.
    http://dx.doi.org/10.1016/j.fertnstert.2013.07.2002
  4. Anna M. Musters, M.D., Sjoerd Repping, Ph.D. et al. Pregnancy outcome after preimplantation genetic screening or natural conception in couples with unexplained recurrent miscarriage: a systematic review of the best available evidence. January 10, 2011. DOI: https://doi.org/10.1016/j.fertnstert.2010.12.022

Medical advice from: Dr. Tan Chong Seong, IVF expert, Malaysia

Reviewd by: Dr. Meenakshi, PhD

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