Congenital Cytomegalovirus Infection Predicted in High-Risk Pregnant Women

In the USA over 8,000 children a year suffer from the long-term complications of congenital CMV infection and the annual costs of caring for these children are estimated at USD 1-2 billions. To facilitate this, early diagnosis is vital; however, tests to identify the infection in infants, such as molecular tests that detect virus DNA in infants' urine, are not widely carried out, and would incur huge financial costs if they were carried out for all infants.

Scientists affiliated with the Kobe University Graduate School of Medicine (Kobe, Japan) surveyed 300 pregnant women who tested positive for CMV immunoglobulin M (IgM) antibodies and were classified as high-risk for congenital infection. The team carried out clinical interviews, blood tests, ultrasounds, and DNA polymerase chain reaction (PCR) tests for CMV using samples of the subjects' blood, urine and uterine cervical secretion. The maternal clinical and laboratory findings, including serum CMV IgM and IgG, IgG avidity index (AI), direct immunoperoxidase staining of leukocytes with peroxidase-labeled monoclonal antibody (C7-HRP test) testing, and PCR for the detection of CMV-DNA in the maternal serum, urine, and uterine cervical secretion, and prenatal ultrasound findings were evaluated.

The team reported that in 22 of the 300 women, congenital infection was confirmed using PCR for CMV-DNA in newborn urine. Univariate analyses demonstrated that the presence of maternal flu-like symptoms, presence of ultrasound fetal abnormalities, serum titers of CMV IgM, positive results for C7-HRP, CMV IgG AI less than 40%, and positive PCR results in the uterine cervical secretion were statistically associated with the occurrence of congenital CMV infection. Multivariable analysis revealed that the presence of ultrasound fetal abnormalities and positive PCR results in the uterine cervical secretion were independent predictive factors of congenital CMV infection in CMV IgM-positive women.

The authors concluded that both ultrasound and PCR tests for uterine cervical secretion are non-invasive procedures, and using them can offer a safer method to test high-risk pregnant women and predict the occurrence of congenital infection. Accurately identifying the affected infants enables doctors to start antiviral treatment early, and could improve the neurological prognosis of infants infected by CMV. The study was published online on October, 20, 2016, in the journal Clinical Infectious Diseases.

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Kobe University Graduate School of Medicine