Welcome to the Canadian CMV Foundation’s blog! In our first post, we’ll dive into the important topic of congenital cytomegalovirus (cCMV), shedding light on its causes and symptoms. CMV is a common virus that can have serious implications, particularly for pregnant women and their unborn babies. By understanding the basics of CMV, we can take steps toward prevention, early detection, and informed decision-making.

What is congenital cytomegalovirus (cCMV) and how is it transmitted?

Congenital CMV refers to the transmission of cytomegalovirus from a pregnant woman to her unborn child. CMV is a member of the herpes virus family and can affect individuals of all ages. However, it poses the greatest risk to fetuses when a woman becomes infected with CMV during pregnancy or experiences a reactivation of a previous infection.

Congenital CMV is primarily transmitted through bodily fluids, including saliva, urine, blood, and breast milk. The most common modes of transmission involve close contact with young children, sharing utensils or drinks, and intimate contact, such as kissing or sexual activity. When pregnant women become infected with CMV through these means, the virus can be passed to their unborn child through the placenta. There are several ways in which this transmission can occur:

  • Primary Infection: If a woman contracts CMV for the first time during pregnancy, it is referred to as a primary    infection. This carries a higher risk of transmission to the fetus compared to recurrent infections.
  •  Reactivation of Past Infection: Women who have had CMV in the past may carry the virus in a dormant state      within their bodies. If the virus reactivates during pregnancy, there is a possibility of transmission to the    fetus.
  •  Person-to-Person Transmission: CMV is commonly spread through close contact with infected individuals.    Pregnant women who come into contact with young children, particularly toddlers and preschoolers, are at    a higher risk of contracting the virus.
  • Transplacental Transmission: Once a pregnant woman becomes infected with CMV, the virus can cross the    placenta and infect the developing fetus. This transmission can occur at any stage of pregnancy but is more    likely to happen during the first trimester.
  • Breast Milk Transmission: In rare cases, CMV can also be transmitted to the newborn through breast milk if    the mother has a current CMV infection or a recent primary infection.

What are the symptoms of congenital CMV?

While some infants born with congenital CMV may appear healthy at birth, others may experience symptoms or long-term complications. The signs and symptoms can vary widely, ranging from mild to severe, and may include:

  • Hearing loss or hearing impairment
    Hearing loss is one of the most common long-term effects of congenital CMV. Some babies may have mild hearing loss, while others may experience more severe hearing impairment.
  • Vision problems or vision impairment
    CMV can affect the eyes, leading to vision problems such as retinitis or optic nerve abnormalities.
  • Developmental delays or cognitive impairments
    Children with congenital CMV may experience delays in reaching developmental milestones, including motor skills, language, and cognitive abilities.
  • Small head size (microcephaly)
    CMV infection during pregnancy has been associated with microcephaly, a condition characterized by a smaller-than-normal head size and potential neurological issues.
  • Jaundice (yellowing of the skin and eyes)
    Some infants with congenital CMV may develop jaundice shortly after birth.
  • Enlarged spleen or liver
    In some cases, congenital CMV can cause enlargement of the spleen or liver.
  • Seizures
    Infants with severe congenital CMV may experience seizures due to neurological complications.
  • Problems with the lungs or breathing difficultiesCMV infection can affect the respiratory system, leading to breathing difficulties in some cases.

It’s important to note that not all infants born with congenital CMV will exhibit immediate symptoms. Some may develop complications later in infancy or childhood. Regular medical check-ups and CMV screening can aid in early detection and timely intervention.


Congenital CMV is a significant health concern, and understanding its causes and symptoms is crucial for expectant parents, healthcare providers, and the general public. By recognizing the modes of transmission and being aware of the potential symptoms, we can take proactive measures to prevent CMV infection, advocate for screening during pregnancy, and support affected individuals and their families.

Stay tuned for our future blog posts, where we will delve deeper into topics related to CMV prevention, treatments, and support resources. Together, we can raise awareness, foster understanding, and make a positive impact in the lives of those affected by congenital cytomegalovirus.

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If you found this article helpful, we invite you to explore our blog, Congenital CMV Unscripted, to access a wealth of additional resources available on our website.


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