IgM-class antibodies to cytomegalovirus are special immunoglobulins that are produced in the human body in the acute phase of cytomegalovirus infection and are an early serological marker of this disease.

Immunoglobulins M (IgM) are usually the first to appear in the blood (earlier than other types of antibodies). Then their number is gradually reduced (this process can take several months). If an exacerbation of a latent infection occurs, then the IgM level rises again.

It is very important for a pregnant woman to know that she has previously been infected with CMV. This determines whether the virus is dangerous for the fetus and newborn. If a pregnant woman has previously contracted an infection, then the risk to the child will be minimal. During pregnancy, an old infection can progress, but complications in this form are rare. If a pregnant woman has not been infected before, she may become infected for the first time during pregnancy. For the fetus / child, this is very dangerous. During the first infection in a pregnant woman, the virus often enters the child's body. This does not mean that the baby is still sick. Usually the infection is asymptomatic, but in about 10% of cases it leads to congenital pathologies: microcephaly, cerebral calcification, rash, enlarged spleen and liver, decreased intelligence and deafness, which can even lead to death.

Acute Cytomegalovirus infection sometimes also manifests itself in a newborn. With a weakened immune system, for example, there is a risk of CMV for AIDS patients and people taking immunosuppressants (in organ transplants). In this case, Cytomegalovirus infection occurs in a severe form.