In a significant stride toward protecting mothers and their babies, researchers at Tulane University have unveiled groundbreaking findings: mothers with prior exposure to Cytomegalovirus are far less likely to transmit it to their baby, a virus known to cause miscarriages and birth defects. This discovery paves the way for the development of a potential vaccine to safeguard pregnant women and their babies. 

Cytomegalovirus (CMV), a prevalent herpesvirus often contracted unknowingly before childbearing age, typically poses no threat. However, during pregnancy, transmission to the developing fetus can lead to miscarriage, cerebral palsy, and hearing loss. 

While it has long been understood that women facing their first CMV infection during pregnancy are at heightened risk, the protective mechanisms for those previously exposed to the virus remained elusive. 

The study, published in PLOS Pathogens, conducted at the Tulane National Primate Research Center, utilized a nonhuman primate model closely mirroring human CMV infection. Researchers found that when pregnant mothers were initially infected with CMV during the first trimester, transmission to offspring occurred in all cases, resulting in a high rate of miscarriage. 

However, when nonhuman primates with prior CMV exposure were reinfected during pregnancy, their offspring were shielded. A robust immune response in mothers upon reinfection drastically reduced transmission through the placenta, with only one out of five mothers passing the virus to their infants, and no adverse health outcomes observed in any of the offspring. 

Dr. Amitinder Kaur, principal investigator and professor of microbiology and immunology, emphasizes the importance of understanding pre-existing immunity in preventing CMV transmission during pregnancy. This knowledge, she says, is pivotal for the development of an effective CMV vaccine, essential for safeguarding pregnant women and their unborn babies. 

The study’s findings underscore the significance of CMV immunity before pregnancy, as it enables the maternal immune system to shield the baby from congenital CMV transmission if reinfection occurs during gestation. This research holds immense promise for the development of a CMV vaccine, particularly vital in regions with a high prevalence of CMV infections among pregnant women.