How Likely Is CMV Transmission From Donor Sperm?

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My wife and I bought sperm that is CMV+, but I am CMV-. I’ve read the research, and I know it’s unlikely to transmit CMV, but I wanted to know your opinion on it!

—Meg

You’re right — this is very unlikely. The research consistently shows very low rates of cytomegalovirus (CMV) transmission through donor insemination.

This risk is largely theoretical. Having said that, there is a recent case report documenting a possible transmission via intrauterine insemination with CMV-positive donor sperm. This suggests the risk is not zero, but it’s very small.

The reality is that your everyday CMV exposure is almost certainly higher than the risk from donor sperm. CMV spreads through saliva and urine, which means every toddler interaction carries transmission risk. Sharing food with a young child, wiping a runny nose, and changing diapers — all of these expose you to CMV. If you work in childcare or education, or have nieces and nephews you see regularly, these are all much higher risks.

This is really a question of trading off a very small risk against your reasons for choosing this donor. Presumably, you picked this donor for other reasons. If you switch to a CMV-negative donor, you give up some of those characteristics. If everything were equal, a CMV-negative donor would be (very slightly) lower risk. But everything isn’t equal.

Bottom line: the transmission risk here is extremely low, and most people in this situation are likely to proceed with their original donor choice.