During pregnancy:
The main risk for the fetus is due to primary infection, which means the infection of a woman who has never been infected with the CMV virus prior to the current infection.
Non-primary infection occurs in one of the two following ways:
The chance of fetal infection in the case of non-primary infection is only about one percent, but such reinfection might also be harmful. There is currently no method of diagnosing it in lab tests, and the only way to reduce the risk is by taking the precautionary measures detailed above.
The recommendation is not to perform follow-up blood tests on pregnant women who have been infected in the past, since in most cases such an infection cannot be detected through blood tests, and to avoid unnecessary tests and reduce undue stress.
In a baby born after all the results of the tests that the mother performed during the pregnancy were normal (targeted CMV scans and fetal brain MRI), no injuries are expected to develop later in life, except for the risk of hearing problems (frequency of about 10%)[6].
In light of this, children infected in-utero with CMV will remain in follow-up with a pediatric infectious diseases doctor and in auditory follow-up throughout the first years of their lives. It is important to note that even in cases of late hearing loss, there is an anti-viral treatment which has been found to be effective in the prevention of further deterioration, and in certain cases, may even improve the hearing that was impaired due to the virus[7]. You can read more about the treatment further down