Could a Common Childhood Virus Cause Unexplained Infertility?
Human Herpesvirus 6 (HHV-6) is very common early childhood infection causing fever, diarrhea, and sometimes roseola. Fascinating recent research has found that this virus may also cause unexplained infertility in women.
What is This Chicken-Pox Like Virus?
Human Herpesvirus 6 is member of the herpesvirus family. Other human herpesviruses include chicken pox, Epstein Barr virus, and herpes simplex (cold sores, genital herpes). HHP-V was first discovered in 1986. In 2012, researcher discovered that HHV-6 is actually two closely related herpes viruses now known as HHV-6A and HHV-6B. Like other herpesviruses, HHV-6 remains dormant in the body and can become reactivated later in life.
Interesting Factoid: Nine herpesviruses are known to infect humans and HHV-6 was so named because it was the 6th herpesvirus discovered.
HHV-6B is very common in childhood—some studies estimate that almost all humans at one time have had this virus. Very little, however, is known about the prevalence of HHV-6A.
Can HHV-6A Cause Infertility in Women?
Researchers in Italy looking for a possible virus that might cause infertility, biopsied the uteruses of 30 women with unexplained infertility and compared them with biopsies from 36 women who had experienced at least one successful pregnancy.
They found that biopsies from 43% of the women with unexplained infertility were found positive for HHV-6A, compared to 0% of the fertile women. Further they found that the amount of virus present in the infertile women was “significant”. Interestingly, both the infertile and fertile women had about the same amount of HHV-6B in their biopsies, and both were comparable to the general population.
Researchers also found infertile women with HHV6-A had higher levels of natural killer cells in their uterus compared with the fertile women. All women have natural killer cells in the uterus; in fact, they are necessary for a healthy pregnancy. However, the natural killer cells in the women with HHV-6A in this study were significantly different than those found in the fertile women. The natural killer cells in the infertile women who tested negative for HHV-6A, were similar to the control group of fertile women.
“This is a surprising discovery,” said Professor Anthony Komaroff of Harvard Medical School, who was not involved in the study. “If confirmed, the finding has the potential to improve the outcome for a large subset of infertile women.”
Note that this is a small study and will need to be replicated on a larger scale to more fully understand the connection between HHP-6A and unexplained infertility.
Can HHV-6A Cause Miscarriage or Premature Birth?
Preliminary research has found that HHV-6A may increase a woman’s chance of having gestational hypertension, premature birth, and miscarriage. These findings would fit well with the recent Italian research indicating the possible connection between HHV-6A infection and unexplained infertility.
Treatment for HHV-6
We are very early in our understanding of how HHV-6A might be connected to unexplained infertility. No specific treatment for HHV-6 infection has been established. HHV-6 infections in childhood most often need no treatment other than basic care.
As more evidence comes in on the relationship between HHV-6A and unexplained infertility, infertility doctors are investigating the use of antiviral medication to improve the likelihood of success with fertility treatment, such as IVF.
Other Creating a Family Resources You Will Enjoy
- The Purgatory of Unexplained Infertility
- Fastest and Cheapest Way to Get Pregnant with Unexplained Infertility
- Is Unexplained Infertility the Worst?
For More Info on HHV-A contact the HHV-6 Foundation.
Image Credit: sbluerock