CMV and pregnancy – What’s the big deal?

As GPs, we discuss many things with our pregnant patients – folic acid and iodine supplementation, alcohol, smoking, nutrition, listeria, toxoplasmosis etc. Studies have shown that many of us do not discuss cytomegalovirus (CMV) and don’t feel confident giving advice and answering questions about CMV in pregnancy 1.

  1. Why is discussing CMV important?

CMV is the most common congenital infection resulting in childhood disability in Australia. One in 200 babies are born with congenital CMV. While most infected babies are asymptomatic, congenital CMV is the leading cause of sensorineural hearing loss and a known cause of cerebral palsy, intellectual impairment and epilepsy. It is much more common than infections like listeria, toxoplasmosis and salmonella, which many of us routinely discuss 2.  Studies show that pregnant patients want to be educated about CMV 3.

  1. Who is at risk of CMV and what can we tell our patients?

CMV transmission occurs when infected body fluids come into contact with another person’s mucous membranes. Infection with CMV often presents as mild viral symptoms. The infection is common in young children, who can shed high levels of the virus for long periods. People who care for, or work with, young children may be at increased risk of infection. Healthcare workers practising standard precautions are not at an increased risk 4.

Simple behavioural strategies can reduce the risk of infection. RANZCOG’s “Prevention of congenital CMV infection” statement advises that all pregnant women and women trying to conceive, should be given information about CMV prevention as part of routine antenatal or pre-pregnancy care 5. CMV prevention strategies can be summarised as advising your pregnant patient to avoid contact with young children’s saliva (by not sharing food, drinks or utensils, and not kissing a child on the lips), respiratory secretions and urine (good hand hygiene after wiping noses and changing nappies). Patient information resources and posters for your clinic room are available on the Cerebral Palsy Alliance website.

  1. How and when to test for CMV

Case study

Your patient Sarah comes to see you, at 9 weeks gestation, feeling unwell. She has had a fever and has been feeling especially tired. Sarah’s 2-year-old son attends childcare and has “had a cold”. On examination you find Sarah has a red pharynx and cervical lymphadenopathy. Her recent blood tests showed an atypical lymphocytosis.

You explain to Sarah that, while this is likely a simple upper respiratory tract infection, it might be caused by a virus called CMV, that is common in young children. It is important to diagnose CMV infection in pregnancy, as it can cross the placenta and affect the baby. You tell Sarah you would like to do a blood test to check for it. 

You request CMV serology testing with CMV IgG and IgM and CMV IgG avidity if CMV IgG and IgM are positive.

Sarah’s results come back showing CMV IgM positive, IgG positive and low IgG avidity, consistent with recent primary CMV infection. You explain the result to Sarah and discuss that she needs referral to a maternal-fetal medicine unit where she will be given further information about the implications for her pregnancy and options for testing and treatment. This referral is time critical if infection was suspected to be in the first trimester, as treatment may be offered before 14 weeks gestation.

For more information in regards to referring to the Mercy Perinatal clinic please click here.


The information in this article was adapted from the Infections in Pregnancy – What’s new in congenital CMV and syphilis free eLearning module for GPs. If you want to learn more and gain CPD points follow the link to register. Infections in Pregnancy, What’s new in congenital CMV and Syphilis.  

Mercy Hospital for Women, Maternal Medicine Clinic contact information:

  • Mercy Hospital for Women referrals
    Fax: 8458 4205
  • Department of Genetics (fetal intake worker for urgent referrals)
    Phone: 8458 4346
  • Department of Perinatal Medicine reception
    Phone: 8458 4248
    Fax: 8458 4504
  • Fetal surveillance unit/ Pregnancy Day assessment centre
    Phone: 8458 4267


  1. Shand AW, Luk W, Nassar N, Hui L, Dyer K, Rawlinson W. Cytomegalovirus (CMV) infection and pregnancy-potential for improvements in Australasian maternity health providers’ knowledge. J Matern Fetal Neonatal Med. 2018;31(19):2515-2520. DOI: 1080/14767058.2017.1344968
  2. Ssentongo P, Hehnly C, Birungi P, et al. Congenital Cytomegalovirus Infection Burden and Epidemiologic Risk Factors in Countries with Universal Screening: A Systematic Review and Meta-analysis. JAMA Netw Open. 2021;4(8):e2120736. Published 2021 Aug 2. DOI: 1001/jamanetworkopen.2021.20736
  3. Lazzaro A, Vo ML, Zeltzer J, et al. Knowledge of congenital cytomegalovirus (CMV) in pregnant women in Australia is low, and improved with education. Aust N Z J Obstet Gynaecol. 2019;59(6):843-849. DOI: 1111/ajo.12978
  4. Balegamire, S.J., McClymont, E., Croteau, A. et al. Prevalence, incidence, and risk factors associated with cytomegalovirus infection in healthcare and childcare worker: a systematic review and meta-analysis. Syst Rev 2022; 11, 131
  5. RANZCOG statement on Prevention of congenital Cytomegalovirus (CMV) infection, March 2019,

Last reviewed November 16, 2023.