Researchers Develop New Prenatal Screening for Congenital CMV

Cytomegalovirus (CMV), a common virus with often no signs or symptoms presenting in adults, can be dangerous when passed from a mother to her unborn baby. Now, a team of researchers in Japan have found a non-invasive way to detect congenital CMV in high-risk pregnant women.

According to the Centers for Disease Control and Prevention (CDC), more than half of individuals over the age of 40 in the United States have had a CMV infection, and almost one-third of children get CMV by 5 years of age. While CMV infections rarely causes signs or symptoms in infected individuals, the virus stays in the body for life with a healthy immune system preventing it from causing illness. Children and adults with weakened immune systems are more likely to experience symptoms due to a CMV infection, such as fever, sore throat, fatigue, and swollen glands, with more serious symptoms in the eyes, lungs, liver, esophagus, stomach, and intestines.

Pregnant women are at risk of passing on the virus to their unborn child in what is known as congenital CMV; this is when the virus passes from the mother’s blood through the placenta and infects the baby. Congenital infections typically occur when women who have never had CMV and lack the antibodies, contract the virus for the first time during their pregnancies. Nearly one out of every 150 babies are born with congenital CMV, but only about one in five suffer from symptoms or long-term health issues. Initial signs of CMV infection in newborns include premature birth, small size, small head size, seizures, as well as liver, lung, and spleen problems. Prolonged health issues for CMV-infected babies can include hearing loss, vision loss, intellectual disability, muscle weakness, and more. Doctors can diagnose CMV in newborns by testing their saliva, urine, or blood.

Researchers from the Kobe University Graduate School of Medicine recently studied ways to diagnose congenital CMV during the prenatal period, and their study was recently published in the journal Clinical Infectious Diseases. Typically, if a woman is diagnosed with CMV infection during pregnancy, doctors can detect fetal infection through the use of a non-invasive ultrasound or an invasive and potentially dangerous amniocentesis. The research team investigated the use of a novel method for CMV screening deemed to be safe for mothers and fetuses that could be used in common medical practices. They noted that early diagnosis during gestation is important, as doctors can treat CMV-infected infants with antiviral treatment once a baby is born to decrease the risk of health problems.

To develop a cost-effective screening for congenital CMV, the researchers identified 300 women who tested positive for CMV antibodies, and as such, were considered at high risk for congenital infection. The women enrolled in the study participated in clinical interviews, blood tests, and ultrasounds and the research team collected samples of their blood, urine, and uterine cervical secretions to test for the presence of CMV DNA through polymerase chain reaction (PCR). The researchers looked for women reporting cold-like symptoms, tested blood samples for white blood cell counts and viral antigens, checked for signs of recent infection, and conducted ultrasounds to check for fetal symptoms of CMV. The team confirmed congenital infections in 22 of the women participating in the study, and found that the best predictors of congenital CMV were ultrasounds revealing fetal abnormalities and positive PCR screenings for CMV DNA in uterine cervical secretion.

The findings present promising initial evidence that non-invasive ultrasounds and DNA tests can safely and accurately detect congenital CMV, offering expecting mothers a safe and effective method of early screening.