If you’ve had one or more failed IVF cycles, especially with good-quality embryos, it’s normal to wonder why things didn’t work. One surprising answer researchers have found is a hidden virus in the uterus called HHV-6A.
In several studies, HHV-6A was discovered in the endometrial lining of women who had repeated failed embryo transfers. In one group of women with “repeat implantation failure,” about 51 out of 100 tested positive for HHV-6A in their uterine tissue. In contrast, women who had successful pregnancies did not show this virus in their endometrial samples.
HHV-6A does not show up on regular blood tests because it hides inside the cells of the uterus. When the virus is active, it can disrupt the local immune environment—making it harder for the embryo to attach, even when the embryo itself is healthy.
This means you can have perfect hormone levels, a perfect embryo, and perfect timing…
and still have a failed cycle if the uterine environment isn’t welcoming.
Because of this, HHV-6A testing is becoming something more women and clinics consider before repeating IVF. A menstrual-fluid–based HHV-6A test allows you to check for this hidden virus without an invasive biopsy.
If HHV-6A might be linked to failed IVF, the next question many women ask is:
“Is HHV-6A the reason my fertility tests look normal but I still can’t get pregnant?”
Read this article next to find out: “Why Your Fertility Tests Look Normal… but You Still Can’t Get Pregnant.”
References
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Knox K, Doody K. Prospective evaluation of human herpesvirus 6 (HHV-6) in endometrial biopsies of women with repeat implantation failure. ASRM Poster. 2019.
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Marci R, Gentili V, Bortolotti D, et al. Presence of HHV-6A in endometrial epithelial cells from women with primary unexplained infertility. PLOS ONE. 2016.
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Liu Z, Chen F, Li Y, Pratt P, Knox K. HHV-6 infection is correlated with uterine polyp and endometrial adhesion in infertile women. SRI Abstract. 2020.