A recent review from the Departments of Medicine and Obstetrics/Gynecology at Harvard Medical School and the University of Ferrara, Italy, summarizes evidence linking HHV6-A/B to several important reproductive diseases: primary unexplained infertility, preeclampsia, congenital infection and, possibly, spontaneous abortion and intrauterine growth restriction.
Mothers with iciHHV6 have an increased risk of spontaneous abortion
27.6% of Japanese mothers with iciHHV6 had a spontaneous abortion compared to 14.8% of controls. iciHHV6 mothers were also 6.4X more likely to have two or more spontaneous abortions.
Fetal iciHHV-6 associated with a 3-fold increased risk of preeclampsia
A large UK study utilizing RNA sequencing metagenomics of placental samples identified HHV-6 RNA in 6.1% of pre-eclampsia cases and 2.2% of healthy pregnancies. HHV-6 was the only virus found and it was iciHHV-6 in 70% of cases.
2nd study implicates HHV-6A in unexplained infertility
In 2016, Italian investigators found HHV-6A in the uterus of 43% of women with unexplained infertility but 0% on controls. Now, a second study found localized HHV-6 infection in women with recurrent implantation failure, but not in controls.
HHV-6A, infertility and miscarriage: a hypothesis
Growing evidence implicates HHV-6, especially HHV-6A, in some cases of female infertility, miscarriage, and other gestational problems affecting both the mother and child. The authors of the paper wonder if heparin, an anticoagulant with antiviral properties often used to treat infertility, might mitigate the detrimental effects of HHV-6 in the uterine environment.
ciHHV-6B activation and fetal transmission in response to high dose progesterone?
A pregnant ciHHV-6B woman with a history of miscarriages was given weekly doses of high dose progesterone. Could progesterone, like hydrocortisone, activate integrated ciHHV-6 in vitro.
HHV-6A infection of the uterus linked to infertility
A new study reported that HHV-6A infects the lining of the uterus in 43% of women with unexplained infertility but cannot be found in uterine lining of fertile women. Furthermore, the cytokine and the natural killer cell profiles were very different in patients with the infection. HHV-6A was found only in uterine endothelial cells, and not in the blood.
Pityriasis rosea, HHV-6, and the increased risk of miscarriage
Italian study finds 62% of women who developed PR early in their pregnancies miscarried
Does HHV-6 infection of the sperm contribute to infertility?
A group of researchers from Denmark have shown that HHV-6B binds specifically to the acrosome of sperm