Pregnancy 2022

Citomegalovírus IgG: what é and how to understand the result

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Citomegalovírus IgG: what é and how to understand the result
Citomegalovírus IgG: what é and how to understand the result

The IgG test for cytomegalovirus is a serological test that aims to assess whether the person has antibodies against the cytomegalovirus virus (CMV), which are normally formed after an infection with this virus. This test is mainly indicated during pregnancy, and is usually performed together with the IgM dosage, to find out if there is a past or recent infection and, thus, it is possible to start the most appropriate treatment, if necessary.

It is very important that this test is carried out in the first trimester of pregnancy, because if the woman is infected during this period, there is a greater chance of being transmitted to the baby and leading to complications, such as microcephaly, congenital deafness and epilepsy, for example.

Although it is frequently requested during pregnancy, the IgG test for cytomegalovirus can be recommended for all people, especially when there is a suspicion of infection. Learn more about cytomegalovirus.

What does IgG reagent mean

A reactive IgG result for cytomegalovirus indicates that the person has antibodies against the virus, which could be due to a past or recent infection. Reference values ​​for cytomegalovirus IgG may vary according to the laboratory, however the serological test is considered positive or reactive when greater than or equal to 1 U/mL.

It is important to note that a positive result or IgG reagent does not necessarily indicate that the infection is active. For this, it is important to perform the IgM test for cytomegalovirus, since this immunoglobulin is the first to be produced when there is an infection.Learn more about IgM and IgG.

How to confirm cytomegalovirus infection

Symptoms of a cytomegalovirus infection are non-specific, including muscle pain, fever above 38°C or sore throats. In addition, in many cases there are no symptoms at all, as the virus can remain dormant for a long time. For this reason, the best way to confirm the infection is to make a medical diagnosis.

The diagnosis is made with the CMV blood test during pregnancy, and the result can be:

  • Non-reactive or negative IgM and positive or positive IgG: the woman has had contact with the virus for a longer time and the risk of transmission is minimal.
  • IgM reagent or positive and IgG non-reactive or negative: acute cytomegalovirus infection is more worrying, the doctor should guide the treatment.
  • IgM and IgG reactive or positive: an avidity test should be performed. If the test is less than 30%, there is a greater risk of infection of the baby during pregnancy.
  • IgM and IgG non-reactive or negative: there has never been contact with the virus and, therefore, preventive measures must be taken to avoid a possible infection.

When an infection is suspected in the baby, a sample of amniotic fluid can be taken to assess the presence of the virus. However, according to the Ministry of He alth, the examination of the baby should only be performed after 5 months of pregnancy and 5 weeks after the pregnant woman is infected.

How to handle to avoid transmission

Treatment for cytomegalovirus in pregnancy should be done according to the obstetrician's guidance, and the use of antiviral drugs, such as Acyclovir, for example, or immunoglobulin injection, which aims to stimulate the immune system and fight infection, preventing transmission to the baby. During treatment, the doctor should regularly indicate that tests are carried out to monitor the baby's development and ensure that the virus is not causing changes.Learn more about treating cytomegalovirus in pregnancy.

What to do to prevent infection in pregnancy

Since there is still no vaccine to help protect against the virus, it is important that pregnant women follow some general recommendations to avoid infection, such as:

  • Using a condom in intimate contact;
  • Avoid going to public places with many people;
  • Wash your hands right after changing a baby's diaper or whenever they come into contact with the child's secretions, such as saliva, for example;
  • Do not kiss very young children on the cheek or mouth;
  • Do not use objects that belong to the child, such as cups or cutlery.

Children are the main responsible for the transmission of cytomegalovirus, therefore, these recommendations should be followed by pregnant women throughout pregnancy, especially if working with children.

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