Cytomegalovirus in pregnancy: everything you need to know

Cytomegalovirus (CMV) is a genus of herpesvirus found within the subfamily Betaherpesvirinae. These pathogens usually invade the salivary glands of the person, but are only considered lethal in those who are immunocompromised or in fetuses during pregnancy.

According to the National Library of Medicine of the United States, 50% to 80% of adults in this country have contracted the infection at some point in their life. Also, once the virus is contracted, it remains in the person forever.

How does this pathogen affect newborns? What is the severity of this clinical picture in babies? In the next space we will tell you what happens when the infection occurs during pregnancy.

Causes of Cytomegalovirus Infection in Pregnancy

Seroconversion due to primary infection during pregnancy has a prevalence of 1% to 7%, according to studies. Simply put, this means that 1 to 7 out of 100 babies will deal with the virus transmitted by the mother before they are born.

Do not panic. This does not mean that all babies in contact with cytomegalovirus are at risk. And, to prove it, we present the following information:

  • The fetal transmission rate during the first trimester is 36%. The percentage of symptomatic babies who become infected at this stage is 25%.
  • In the second trimester of pregnancy, the percentage of transmission if the mother is infected increases up to 40%. Here only 5-10% of babies have symptoms.
  • The fetal transmission rate during the third trimester is 65%. From 28 weeks of gestation, infected babies are asymptomatic.

What does all this mean? Well, even if a mother has the virus in the first trimester of pregnancy, there is less than a 40% probability that she will transmit it to her baby and, in addition, only 1 in 4 of infants infected at this stage will have symptoms.

As much as the transmission rate increases over time, this is not a problem, since almost all babies are asymptomatic after a certain point during pregnancy. Therefore, it is estimated that only 10-15% of infected newborns as a whole develop symptoms. You need to provide this data to put the situation in perspective.

In most cases, cytomegalovirus infection in pregnancy does not pose a risk to the fetus.

To know more: Diet to prevent gestational diabetes

How is it transmitted to the baby?

Cytomegalovirus is transmitted from the mother to the child transplacentally, that is, through the blood that connects the fetus and the mother. In any case, it should be noted that, as indicated by studies, the probability of transmission is much higher when the infection is acquired during pregnancy (50%) than when it is reactivated (2%) in the mother.

On the other hand, adults are usually infected by contact with fluids such as saliva, urine, blood, feces, vaginal discharge, semen, among others. Babies can also contract the virus during the time of delivery or through breast milk, although this is not a significant clinical problem.

In summary: only 1 in 10 children infected with CMV will present some type of symptom.

Symptoms of cytomegalovirus infection

As we have already reiterated, most newborn children are asymptomatic despite having been infected, especially if this event has happened during the third trimester. Even so, the Mayo Clinic shows us the most common symptoms of babies with congenital cytomegalovirus that do show clinical signs. These are as follows:

  • Premature birth.
  • Low birth weight
  • Yellow skin and eyes (jaundice). This represents poor liver function, as bilirubin accumulates in tissues when it shouldn't.
  • Purple spots on the skin and other rashes.
  • Abnormally small head (microencephaly)
  • Enlarged spleen
  • Pneumonia.
  • Seizures

Nor should we forget that adults with compromised immune systems can also develop severe symptoms from infection. Organs such as the liver, lungs, eyes, digestive system, and brain can be affected in these weak patients.

How can it be treated?

The portal Kidshealth indicates that cytomegalovirus, in both adults and infants, can be treated, but this is rarely necessary. In infants with symptoms, the administration of antiviral medications intravenously (IV) or orally, according to your needs.

It should be noted, however, that these drugs can delay the multiplication of the virus, but do not eliminate it. It is the newborn's immune system that must fight the infection. To date, new routes are being studied to combat this pathogen, as there are no effective vaccines to prevent it.

Also read: Herpes zoster in children: causes, symptoms and treatments

What precautions can be taken?

According to the Centers for Disease Control and Prevention (CDC), doctors do not usually test pregnant women for cytomegalovirus, as the presence of the pathogen in the mother does not guarantee contagion to the baby.

Even so, Certain precautions can be taken to avoid infection during or after childbirth. Among them, we find the following:

  1. Wash hands frequently: Especially if one of the parents is going to come into contact with the baby or with their cleaning supplies.
  2. Avoid contact of saliva and tears between the parents and the infant.
  3. Clean toys and all elements of the newborn's environment regularly.
  4. Maintain safe sex, as cytomegalovirus can be spread through sexual contact.

Proper hygiene when having contact with the baby is essential to avoid this type of infection.

A virus that is rarely a problem

With all this set of statistics and percentages we have wanted to demonstrate scientifically that, indeed, cytomegalovirus in pregnancy is almost never a problem. Very few babies are infected, and of those who do, only 1 in 10 develop symptoms of it. For this reason, there is no need to worry about more.

Anyway, it never hurts to take precautions during and after pregnancy, not only because of cytomegalovirus, but also because of other pathogens that can be easily transmitted to the newborn.