KIR genes and HLA-C testing: Why are you unable to conceive even though you have high-quality embryos?
21.10.2025 · 3 min reading
Discover a lesser-known cause of infertility that is often overlooked by standard tests.When you are unable to conceive – despite repeated attempts or even though the laboratory reports high-quality embryos thanks to the ICSI method – there may be "something" to blame that common tests do not reveal. This is where testing for KIR genes and HLA-C comes in.
What are KIR genes and HLA-C?
- Every woman has KIR genes – these are genetic “switches” for her natural immunity.
- HLA-C antigens, on the other hand, are carried by every embryo – and in the case of IVF, also by embryos from donated eggs.
When these two components do not combine ideally, a woman’s body may “overreact” and reject the embryo, even if it is otherwise healthy.
Why is it important to undergo these tests?
Because they reveal whether your body can help the embryo implant successfully in the uterus.
When does it make sense to test for KIR and HLA-C?
- If you have had several unsuccessful transfers.
- If you have had repeated miscarriages.
- If you have had pre-eclampsia, HELLP syndrome or foetal growth restriction in a previous pregnancy.
- If you have undergone IVF with donated eggs and the treatment was unsuccessful.
- If you want to rule out a possible immune cause of treatment failure in advance.
What can testing reveal?
KIR and HLA-C testing helps to determine whether the embryo’s surface antigens can activate the cells responsible for the proper implantation process in the uterus. Otherwise, the embryo acts as a switch and the implantation process either does not start at all or proceeds incorrectly, resulting in a miscarriage.
How can KIR and HLA-C testing help you?
Thanks to this test, we can:
- better match the egg donor with the recipient,
- choose the right treatment protocol,
- reduce the risk of unsuccessful embryo implantation and miscarriage style
- and increase the chances of successful embryo implantation.
How is KIR gene and HLA-C testing performed? Quickly, easily and painlessly.
Just a few drops of blood – and you will know the result within a few days.
Your doctor will explain the results to you in detail and, based on them, recommend the next step in your infertility treatment.
What if the immune system and the embryo are not compatible?
In some women, the body may perceive the embryo as a foreign element – even if everything else is fine. This condition is technically called immune incompatibility between KIR genes and HLA-C antigens. In practice, this means that the chances of embryo implantation may be significantly reduced – to as low as 10%.
KIR and HLA-C testing as part of the IVF programme
At Europe IVF, we offer this testing to couples who have repeatedly failed to achieve success, even though their embryos are of good quality.
- If you are undergoing treatment with donated eggs, we can select a genetically compatible donor for you to minimise the risk of immunological conflict.
- For couples who use their own gametes, we are preparing to offer treatment with the white blood cell growth factor filgrastim. This can influence the immune system’s response to make it more receptive to the embryo.
This approach is based on international studies with very positive results.
https://www.sciencedirect.com/science/article/abs/pii/S0165037824001190
https://gyne-kreis-6.ch/userfiles/file/G-CSF%20in%20ART%20RBMO2019.pdf
Europe IVF – one of two IVF clinics in the Czech Republic involved in infertility treatment research
Modern reproductive medicine , an individual approach and higher chances of success.
Europe IVF is one of only two clinics in Czechia participating in specialised research in the field of assisted reproduction. This puts us one step ahead in infertility treatment. We combine the latest scientific findings advanced IVF methods and an individual approach to significantly increase your chances of getting pregnant.
We want science our experience style and empathy to work together. We have a common goal: to help you become parents.
This is our mission, “Parents 2025”.
The KIR/HLA-C test is a small step that can make a big difference
Invisible factors in the immune system can stand between you and your baby. If you have had several unsuccessful attempts, this test may provide new answers – and new opportunities.
Have you had unsuccessful IVF without results?
Contact us – we will be happy to advise you on whether KIR/HLA-C testing makes sense in your case.
