Cytomegalovirus Infection – what is the risk during pregnancy?

Cytomegalovirus is a disease that can have serious consequences for the developing baby in the womb. Therefore, pregnant women should undergo a test to detect the virus. Learn about the risks of a cytomegalovirus infection during pregnancy.

Cytomegalovirus (CMV) is a virus belonging to the Herpesviridae family. It is known that up to 8 of its species can cause an infection in humans. The virus has one of the largest genomes among microorganisms and can produce hundreds of proteins. It enters the host by attaching its glycoproteins to receptors on human cells. The pathogen is widespread worldwide, with most infections being reported in developing countries among lower socioeconomic groups. Cytomegalovirus is very dangerous for the fetus.

Cytomegalovirus – what kind of disease is this?

Cytomegalovirus is a disease caused by the cytomegalovirus. It affects the entire body and can occur at any age. It occurs in both children and adults. It is estimated that up to 70% of preschool-aged children become infected from their peers. In infants, parents are the source of the pathogen. In contrast, about 1% of all infections are congenital and can occur at any stage of pregnancy.

In most people with a healthy immune system, cytomegalovirus does not cause symptoms. In some cases, the infection manifests as cytomegalovirus mononucleosis. The following symptoms are observed in these cases:

• Enlarged lymph nodes
• Enlarged liver
• Muscle and joint pain
• Fever
• General weakness

The symptoms usually subside spontaneously after a few days and typically do not result in any lasting effects. Cytomegalovirus infection can also take the form of viral hepatitis. In such cases, adults may develop jaundice. On the other hand, severe immunosuppression (e.g., due to HIV infection) leads to a more severe course of the disease. Patients may develop interstitial pneumonia, retinitis, and encephalitis. The digestive organs may also be affected.

Cytomegalovirus penetrates the endothelium in the human body. It also infects immune system cells: leukocytes and lymphocytes. In the body of the infected person, antibodies of classes IgM and IgG are produced.

How is cytomegalovirus infection transmitted?

Sources of infection for cytomegalovirus are all body fluids, especially saliva, genital secretions, blood, urine, semen, and breast milk. The carrier transmits the pathogen to another person through direct contact. Therefore, there is a high risk of transmission to the fetus (via the placenta) and even during childbirth. It is difficult to protect against cytomegalovirus, so it is better to avoid direct contact with people, especially children, who belong to the risk group during pregnancy.

The most common source of infection for pregnant women with cytomegalovirus is children under the age of two. This is because many of them are asymptomatic carriers. On average, they shed the virus in saliva or urine for 24 months. The risk increases with frequent and prolonged contact. Therefore, mothers of preschool children, as well as educators and daycare providers, are particularly at risk.

Cytomegalovirus is widespread in the population. It is estimated that up to 80% of the adult population are asymptomatic carriers. In these individuals, the pathogen remains in an inactive form in the body’s cells. For most, the infection is very mild or asymptomatic.

Statistics show that up to 90% of women of childbearing age have been in contact with cytomegalovirus. Most of them are unaware of their carrier status because they have no symptoms. However, it is important to note that a dormant virus can reactivate – this usually happens when immunity is weakened. Reactivation in the mother’s body is also dangerous for the developing fetus. However, the risk of transmission to the child is lower in this case (compared to a primary infection during pregnancy).

What symptoms does cytomegalovirus cause during pregnancy?

Cytomegalovirus during pregnancy is usually asymptomatic. The symptoms that occur are not specific to a cytomegalovirus infection and may be misinterpreted as a cold, flu, or other upper respiratory infections. The expectant mother often only realizes that the virus has entered her body after a laboratory test.

What risks does cytomegalovirus pose during pregnancy?

Cytomegalovirus during pregnancy is primarily dangerous for the developing baby. The infection can occur at any stage of pregnancy and during natural childbirth. The side effects of the infection manifest at different times. Some of them are observed during the newborn period, while others may not appear until preschool or school age.

Cytomegalovirus during pregnancy can lead to the following symptoms, among others:

• Birth defects in the child
• Intrauterine growth restriction of the fetus
• Progressive hearing loss
• Delayed psychomotor development
• Delayed intellectual development
• Vision impairment
• Microcephaly
• Impaired muscle tone
• Hydrocephalus
• Nystagmus
• Anemia
• Epilepsy
• Digestive system disorders
• Cerebral palsy

It is also possible that cytomegalovirus during pregnancy does not cause any anomalies in the baby. The situation is particularly dangerous if the infection occurs during the first trimester. This is the period when most internal organs and systems – especially the nervous system – form and develop.

How is cytomegalovirus diagnosed during pregnancy?

Cytomegalovirus during pregnancy can be diagnosed with laboratory blood tests. The diagnosis is made if specific antibodies of classes IgM and IgG are present in the blood. However, the presence of these antibodies does not necessarily mean that contact with the pathogen occurred during pregnancy.

It is also important to know that the presence of antibodies in the mother does not mean that the child is infected. The first signs of viral transmission can be detected during an ultrasound examination (USG). The doctor may observe abnormalities in the fetal anatomical development (e.g., microcephaly). It is also possible to conduct an amniocentesis to detect cytomegalovirus in the amniotic fluid.

When should you get tested for cytomegalovirus during pregnancy?

It is recommended to test for cytomegalovirus during the first trimester of pregnancy. However, this test is not mandatory and is not included in the routine screening schedule. Therefore, the decision to undergo this test should be discussed with your doctor. A cytomegalovirus test during pregnancy is recommended for all expectant mothers. Some women choose to have this test already during the planning stage of their pregnancy.

It is also advisable to get tested during pregnancy if a woman notices symptoms of an infection. This should be reported to the treating physician, who will then decide on further treatment.

Is cytomegalovirus during pregnancy an indication for a cesarean section?

During a natural birth, there is a risk that the child may become infected with cytomegalovirus. Therefore, doctors generally opt for a cesarean section for women with a confirmed laboratory infection. This reduces the risk of transmission of the pathogen.

Treatment of cytomegalovirus during pregnancy

The treatment of cytomegalovirus during pregnancy is carried out if symptoms of the disease are present. The therapy aims to alleviate the symptoms. Antiviral medications (which inhibit the virus’s replication) cannot be administered to the pregnant woman, as they may be harmful to the developing baby. An infection that runs without symptoms is usually not complicated for the mother. Cytomegalovirus during pregnancy is mainly dangerous for the fetus.

Currently, there is no treatment known for congenital cytomegalovirus in the child. The infant should remain under close medical supervision. Measures are taken to alleviate the symptoms. Regular ophthalmological, audiological, and neurological examinations are necessary.

Cytomegalovirus and the storage of cord blood

An important question is how cord blood storage works if cytomegalovirus is confirmed during pregnancy. In this case, the collected material does not need to be discarded. The decision should be made in consultation with an infectious disease specialist.

What about women who were not tested for cytomegalovirus during pregnancy? Any collected cord blood is tested in the stem cell bank laboratory. If antibodies against cytomegalovirus are detected, it is not always decided to discard the material. However, additional tests are required to determine if the child has congenital cytomegalovirus.

How can cytomegalovirus infection be prevented during pregnancy?

Preventing cytomegalovirus during pregnancy is difficult due to the widespread nature of the virus in the population. The key is strict adherence to hygiene rules. The most important rules are:

• Wash hands frequently with warm soapy water (especially after coming home, after contact with children, after changing diapers, after touching children’s toys)
• Avoid using the same utensils as the child
• Avoid drinking from the child’s cups and bottles
• Avoid close contact with children (especially kissing)
• Frequently disinfect surfaces and objects (especially those that have come into contact with the child’s saliva)

Unfortunately, there is no vaccine that can protect against cytomegalovirus infection. Research into the development of such a vaccine is still ongoing. There is also no population screening to identify individuals who are carriers of the virus. However, it is certain that the majority of the population are asymptomatic carriers. It is also important to remember that the presence of antibodies against cytomegalovirus in the body does not protect against re-infection.

It is very important to know that there is no contraindication to breastfeeding if cytomegalovirus is detected in the milk. The baby can become infected this way. However, in most cases, the infection is asymptomatic.