CMV (Cytomegalovirus) in Pregnancy

Cytomegalovirus (CMV) is a commonly encountered virus in human beings. It causes a mild infection in adults which does not pose any severe health problem, and the body can combat it without any special treatment. Although that’s the case in adults, this virus must be treated more seriously during pregnancy. Pregnant women can contract the virus, which can potentially cause congenital CMV in newborns.

What Is Cytomegalovirus?

Cytomegalovirus belongs to the virus family Herpesviridaeis and is known to be one of the most common congenital viral infection which affects all age groups. Almost everyone encounters this virus in their lifetime. The virus can stay in a healthy person’s body in an inactive form without any symptoms for their entire life, and even if it becomes active, the immune system can fight against it without any treatment. The CMV can cause severe health conditions if the person becomes immuno-compromised which can be a result of HIV infection. Congenital CMV infection is when the baby is born with the infection. It is identified as the leading cause for children developing hearing problems or even hearing loss due to non-genetic reason. CMV and pregnancy are highly discussed since the infection can be a threat to the baby’s health.

How Common Is CMV?

CMV is prevalent and affects the worldwide population. It is estimated that more than 40% of people encounter this virus by the time they are 20 years old. Any form of close contact with an infected person can lead to transmission of the virus to a healthy person.

Causes of CMV Infection

CMV spreads from an infected person to another person through body fluids. This includes saliva, urine, faeces, tears, vaginal secretions, semen, bread milk and any other bodily secretion. CMV infection is not related to food, water or animals. Although it is not a highly contagious disease, it is seen to spread quickly among the household as a result of sharing utensils or close intimate contact with an infected individual. Also, toddlers playing or schooling together have a higher risk of transmitting CMV infection to each other.

Signs and Symptoms of CMV

CMV usually does not present with any symptoms, and the person might not even know he/she is infected. Even if there are symptoms, they are vague and can often be confused with that of a common cold or other viral infection. It’s symptoms generally include:

• High fever (above 100 degrees F)
• Fatigue
• A sore throat
• Muscle and joint pains
• Swollen glands
• Weakness and loss of appetite
• A weakened immune system which paves the way for other infections in severe cases like pneumonia, hepatitis, etc.

This can further worsen the immune system and make the woman susceptible to common pregnancy infections. 

Congenital cytomegalovirus is a condition when the cytomegalovirus is passed on from the mother to the child before birth. It is when the condition is present in the baby at birth. Congenital CMV in pregnancy can happen during any stage where it gets transferred through the placenta to the baby. In these situations, the baby may present with the following conditions:

• Low birth weight and smaller head
• Enlarged liver and spleen
• Jaundice
• Pneumonia
• In the long term, if it is untreated, it can cause hearing loss, visual impairment, etc.

In most cases, the baby may not present with any symptoms at birth but will develop physical or mental problems later.

Diagnosis of CMV

As mentioned earlier, the symptoms of CMV can be easily confused with that of common cold or throat infection. Almost everyone encounters the virus, and once it enters the body, the virus stays inside the body in the dormant state. Diagnosis is made by a simple blood test or sample of any other body fluid or even tissue. If the patient is CMV  positive, the doctor suggests further treatment if required.

If a pregnant woman is detected positive, then the doctor may check if the baby has also got the infection. This is usually done by performing an ultrasound to check for any CMV-related abnormalities and can be followed by carrying out an amniocentesis. In cases of congenital CMV, the doctor must test the baby at birth or within the first two weeks, preferably to ensure that it is congenital CMV.

Risks of Cytomegalovirus

The infection due to CMV is usually mild and does not show any specific symptoms. Unless the person’s immune system gets compromised, the infection does not pose any major health threats. Even with congenital CMV, most babies (about 80%) do not show any signs and also do not develop any complications in the future. However, in the rest, 20%, severe problems may be seen, such as:

• Premature birth
• Enlarged liver or spleen
• Lower birth weight
• Smaller head
• Inflamed lymph nodes

Even though the baby does not show any symptoms at birth, he may develop some of the following conditions later in life, such as:

• Vision loss
• Hearing loss
• Learning disabilities
• Impaired neural development
• Lack of coordination
• Muscle weakness

Effects of CMV on Mother and Unborn Baby

Most pregnant women would already have antibodies against CMV since they would have encountered the virus before in life. Hence the mother does not face any serious threats from the viral infection. However, for the baby, the infection can be dangerous if transmitted.

How Is the Virus Transmitted from the Mom to the Unborn Baby?

CMV exposure in pregnancy can go undetected and get transmitted to the foetus during the term or during delivery. This transmission is possible through the placenta and depends on the stage of pregnancy (when the mother got the infection). If the mother encounters the virus after her first trimester, the chances of the baby being born with congenital CMV are less, but if the mother gets CMV in the early pregnancy, the chances of the baby being born with the infection are higher. Out of these also, the majority do not display any symptoms at birth or even during later stages of life.

Treatment of Cytomegalovirus

Treatment is not required in adults since their immune system is sufficient to fight the infection, but in some cases, the doctor may prescribe antiviral drugs.

How to Prevent CMV Infection

There are simple ways to protect yourself from the infection. Maintaining a hygienic lifestyle, cleaning toys or surfaces which come in contact with saliva or urine, etc. can go a long way in preventing the virus from entering your body. Children that show symptoms of infection should not mingle with other kids till they recover.

What If Your Baby is Born With the Infection?

In babies with congenital CMV, it is essential to undergo proper medication with antiviral drugs as prescribed by the doctor to fight the infection. It is recommended to get regular check-ups done to see any degradation in vision or hearing.

While the virus has little or no effect on adults, it can have a debilitating impact, such as possible impaired hearing, on those children who contract it. As the symptoms of the virus can be confused with those of a common cold, it is advisable for pregnant women to get a CMV IgG test done.

Also Read: Fever during Pregnancy