Cytomegalovirus (CMV) is a virus that can infect people of all ages and demographics. In the majority of healthy individuals, CMV causes mild symptoms or no symptoms at all. However, CMV can pose serious health risks to immunocompromised individuals and to newborns if a mother becomes infected during pregnancy. This concern extends into the realm of reproductive health, particularly with regard to the CMV status of sperm donors. Despite this concern, research is not as convincing regarding the risk of transmission via semen.
Definitions
CMV IgM: This antibody is suggestive of an active CMV infection if positive.
CMV IgG: This antibody is suggestive of a past CMV infection if it is positive but IgM is negative.
Understanding CMV
CMV is part of the herpesvirus family and is widespread across the globe. Once someone becomes infected with CMV, it remains in the body for life, often lying dormant without causing any issues. Despite being dormant, it can continue to exist in bodily fluids, including semen, which brings us to the importance of considering CMV status in sperm donation. For the purpose of this blog, we will be discussing donors with regard to their CMV IgG status, as fertility specialists unanimously agree that donors with an active CMV infection should not be considered.
CMV Status in Sperm Donors
When selecting a sperm donor, many prospective parents and fertility clinics pay close attention to the donor's CMV status, especially when the prospective parent is CMV negative. The primary concern is the potential transmission of CMV from the donor to the recipient and, subsequently, to the fetus. This is particularly significant because a primary CMV infection during pregnancy can lead to congenital CMV infection in the newborn, potentially resulting in birth defects or developmental disabilities.
What Does the Research Show?
Research on CMV and sperm donation has focused on assessing the risks of transmission and developing guidelines to minimize them. Research proves that low levels of CMV can be detected in semen, which suggests that there may be a risk of transmission during an insemination process. Despite this theoretical risk, to date there have been zero reported cases of transmission of CMV from CMV positive frozen donor sperm to a CMV negative recipient parent or fetus. There has been insufficient research to prove that this risk is zero, thus clinics continue to test for CMV to avoid possible liability. Many couples waive this recommendation and opt for a CMV IgG positive donor, even if the recipient parent is CMV IgG negative. In this case, clinics often recommend washing the sperm prior to insemination, as washed samples have reduced CMV viral loads. Ultimately, it is recommended to discussing this theoretical risk with your fertility doctor before making a decision on a donor.
Considerations for Prospective Parents
Prospective parents using donor sperm are encouraged to discuss CMV risks and implications with their healthcare provider or fertility specialist. This conversation should include an understanding of their own CMV status and how it might influence their choice of a sperm donor.
Ongoing Research and Developments
The field of reproductive medicine continues to research CMV and sperm donation, aiming to refine testing methods, improve sperm processing techniques to further reduce any risks of CMV transmission, and develop more precise guidelines for donor selection based on CMV status.