You are pregnant with a toddler, that means that you are taking care of your family and trying to take care of your pregnant self. If you are preparing for baby 2, you are wondering when and how to tell your toddler about the pregnancy and what will be different for you between your first pregnancy vs second pregnancy. We have articles on those topics, but first, we want to share some very important information for women who are pregnant with a toddler about cytomegalovirus (CMV). 

First, we will go through a quick overview of CMV, then explore why it is a serious risk for mothers of children under the age of 5 who are trying to conceive or pregnant. Finally, we will give you some easy ways to protect your unborn baby from this serious infection.

 This is a long one, but we promise it is worth the read to the end!

CMV is in the family of herpesvirus. Like herpes, the virus stays in the body for life. If you have ever had a cold sore then you will always test positive for herpes virus. But, a positive test does not mean that the virus is active. It may be in a latent phase where it is not causing damage or illness.

CMV is transmitted through direct contact with body fluids (urine, blood, saliva, tears, semen and breast milk). It spreads quickly in daycare centers and among household members and children have notably high amounts of this virus in their saliva and urine.

While CMV is very common, most people with CMV don’t have symptoms and aren’t aware that they have been infected. Some people may notice a fever, sore throat, fatigue or swollen glands, but the infection is usually mild in healthy people. 

When a baby is born with a CMV infection it is called congenital CMV (cCMV). And while CMV is normally mild and you are likely unaware if you have ever had it in your life, this is not the case for cCMV. 

In percentages, this means that cCMV can lead to permanent long-term health problems in 15 to 18% of births. What long-term health problems are we talking about? Of individuals with cCMV the following outcomes are reported – death in 1%, neurocognitive problems in 5 to 15% and hearing loss in 12%. 

These percentages are high and the impacts are severe, but maybe you noticed the flip side of those percentages? That about 85% of infants with cCMV will not have long term health problems. That’s great! So how do we find out which babies with cCMV will be okay and which of them need help? This is where it gets complicated and why all pregnant women with toddlers need to take extra precautions.

Only 10-15% of infants with cCMV have symptoms at delivery. Meaning that most babies who are born with a cCMV infection won’t show any signs of infection for weeks, months or even years after birth. These infants, who have cCMV but do not show any symptoms, may go on to develop symptoms later in life – cCMV causes 35% of moderate-to-severe late-onset hearing loss– or may never develop any long-term issues. This is one reason that newborn screening for cCMV, or screening for CMV during pregnancy is complicated – a high percentage of newborns who have cCMV will have no long term consequences of this infection.

The worst part? We don’t have a way to figure out which infants will be okay. So knowing about a cCMV infection creates what is called a “patient-in-waiting” where you may develop an illness or you may not. 

It’s like doing genetic testing and finding out that you have a BRCA mutation. Your doctor will tell you that you have a 45-85% chance of developing breast cancer. That’s a pretty high chance, compared to 15-18% chance. Then what? Is there a treatment? For a BRCA mutation you can get routine screening and a mastectomy, but for cCMV it is not so straightforward. 

For cCMV, there is effective treatment if it is started early enough, but since only 10-15% of infants show symptoms and there is no routine screening, there are infants who have cCMV and are not treated until it is too late. This, again, brings us back to the importance of prevention!

Between 30 and 70% of infants in utero will be infected if their mother gets CMV for the first time during pregnancy. The rate of transmission and the chance of symptomatic cCMV depends on the gestational age at time of infection. The first trimester is the most critical time. The risk of your baby having symptomatic cCMV if you get CMV for the first time during pregnancy goes from 20-30% in the first trimester to 9% in the second trimester. Severe neurological impairments are most common from primary maternal CMV infections in the first trimester. 

Even if you know that you have already had CMV you can get a secondary infection and transmit it to your unborn baby. Your baby is less likely to have problems, but 8% of infected babies whose mothers had a secondary CMV infection during pregnancy had long term neurological problems. That’s still a big number. 

This may have been a scary article to read and it probably took some time to digest all of the numbers. CMV is not routinely screened for in pregnancy, and cCMV is not screened for at birth. It is also not commonly talked about. We hope that with this information you know how to protect your unborn baby if you are pregnant with a toddler.