Prenatal diagnosis of fetal cytomegalovirus infection in seropositive pregnant women

Pitfalls in the Serological Evaluation of Maternal Cytomegalovirus Infection as a Potential Cause of Fetal and Neonatal Involvements: A Narrative Literature Review

Cytomegalovirus (CMV) is the most common cause of intrauterine infection and serological assays are the primary tools for assessing CMV infections during pregnancy. CMV-specific immunoglobulin M (IgM) antibodies have been used as a diagnostic marker for primary CMV infection in pregnant women, although CMV-IgM has been detected in non-primary CMV infections. IgG avidity testing may aid the distinguishing of primary from non-primary CMV infection; however, there is no standardized assay for detecting this difference. Moreover, when maternal serology shows positive CMV-IgG with negative CMV-IgM findings, vertical transmission probability following primary CMV infection is often excluded. However, symptomatic congenital CMV infections in the context of negative findings for maternal CMV-IgM have been reported recently. The absence of CMV-IgM is recognized in both primary and non-primary CMV infections. Furthermore, maternal non-primary CMV infections during pregnancy may yield a greater proportion of symptomatic congenital CMV infections than previously thought. If universal prenatal screening is performed, ultrasonography for abnormal fetal findings should be conducted regardless of CMV-IgM antibody status. If not universally screened, CMV antibody screening should be performed whenever routine fetal ultrasound reveals abnormal findings. For suspected fetal CMV infection, amniotic fluid or postnatal infant urine CMV-DNA testing is required.

Symptomatic congenital cytomegalovirus disease following non-primary maternal infection: a retrospective cohort study

Background

Scarce data exist about screening, diagnosis and prognosis of non-primary Cytomegalovirus (CMV) during pregnancy. We aimed to examine antenatal diagnosis of maternal non-primary CMV infection and to identify risk factors for congenial CMV disease.

Methods

Retrospective cohort of 107 neonates with congenital symptomatic CMV infection, following either primary (n = 95) or non-primary (n = 12) maternal CMV infection. We compared the groups for the manifestations and severity of congenial CMV disease, as well as for possible factors associated with the risk of developing CMV related infant morbidity.

Results

Disease severity is not similar in affected newborns, with a higher incidence of abnormal brain sonographic findings, following primary versus non-primary maternal CMV infection (76.8% vs. 8.3%, p < .001). Symptomatic congenital CMV disease following a non-primary infection is more frequent if gestational hypertensive disorders and/or gestational diabetes mellitus have ensued during pregnancy (33.3% vs. 9.9%, p <0.038), as well as if any medications were taken throughout gestation (50% vs. 16.8%, p <0.016). CMV-IgM demonstrates a low detection rate for non-primary maternal infection during pregnancy compared to primary infection (25% vs. 75.8%, p = 0.0008).

Conclusion

Non-primary maternal CMV infection has an impact on the neonate. Although not readily diagnosed during pregnancy, knowledge of risk factors may aid in raising clinical suspicion.

Umbilical cord blood transplantation and cytomegalovirus: Posttransplantation infection and donor screening

This study assessed the incidence of cytomegalovirus (CMV) infection after transplantation of cord blood (CB) from unrelated donors and evaluated strategies for screening CB donors. Posttransplantation CMV infection, reported in 23% of 1221 CB recipients, was associated with patient pretransplantation CMV serology (P < .001), but not with CMV serology in CB donors or their mothers. A total of 26 988 infant CB donors were evaluated by viral culture of saliva. Subgroups were evaluated by polymerase chain reaction in CB (CB-PCR) in 2 case-control studies. In the first study, 33 of 47 saliva culture-positive CB donors were confirmed by CB-PCR. All mothers of the 33 infants with confirmed CMV infection were CMV-total antibody positive, but only 1 of 3 had CMV-IgM antibody. The second study evaluated infants born to mothers with CMV-IgM antibody. Of these, 5 of 170 saliva culture-negative infants were positive by CB-PCR. The incidence of congenital CMV infection in CB donors was low (0.12%). Maternal serology had poor predictive value for CMV infection in their infant CB donors and bore no detected relationship to CMV infection in CB recipients. Saliva culture for CMV had both false-positive and -negative results. CB-PCR was a useful alternative for detecting CMV in CB donors.

Mother-to-fetus transmission of cytomegalovirus. A review

Congenital human cytomegalovirus (CMV) infection is the leading infectious cause of mental retardation, sensorineural deafness and visual impairment. It is mainly related to a primary maternal infection. The placenta should be considered the most important site of both the protection of the fetus from CMV infection and the transmission of CMV from mother to fetus. The control of the passage of CMV across the placenta probably involves a cascade of regulatory events. Roles are played by factors relating to the host immune-selective pressures, such as local cytokines and maternal CMV-specific neutralizing antibodies. The presence of other pathogens at the maternal-fetal interface also influences the outcome of CMV infection. Further investigations are needed in which clinical CMV strains are applied in in vitro studies to unravel the molecular mechanism of the intrauterine transmission of CMV and to elucidate the complex regulation that leads to prevention of the in utero transmission of CMV in vivo.

Development and application of a PCR-based method including an internal control for diagnosis of congenital cytomegalovirus infection

Cytomegalovirus (CMV) is the most common cause of congenital infection in the developed world. We have designed and evaluated an assay that includes an internal control for amplification and detection of CMV DNA in amniotic fluid and neonatal urine samples. We present data on the use of this assay in the diagnosis of congenital CMV infection. A total of 145 amniotic and fetal fluid samples were examined by this assay; 83 were from healthy pregnant women and 62 were from women who were being investigated because of concerns over the pregnancy (diagnostic group). CMV DNA was detected in three amniotic fluid samples from the diagnostic group but was not detected in any samples taken from healthy pregnant women. Thirty-nine urine samples were obtained from 19 neonates with suspected congenital infection; CMV DNA was detected in urine from 6 of these patients. The assay provides useful information about CMV infection in the fetus and the neonate; when used in conjunction with other diagnostic tools it will enable mothers and obstetricians to make informed decisions about the management of pregnancies complicated by CMV infection.

Prevalence of maternal cytomegalovirus (CMV) antibody and detection of CMV DNA in amniotic fluid

The prevalence of cytomegalovirus (CMV) IgG antibody was determined in 573 pregnant women in the first trimester. The overall prevalence of CMV IgG antibody was 77.5%. The rate of seropositivity was 67.7% in women < 25 yr, and increased with age to 85.7% in women 40 yr. These results imply that young women in Japan are at increased risk for primary CMV infection during pregnancy and that congenital CMV infection rates might increase in the future. We conducted a prospective study of 75 pregnant women who underwent amniocentesis for various indications to determine if CMV DNA could be detected in the amniotic fluid. None had symptoms associated with CMV infection, CMV IgM antibody, or seroconversion to CMV IgG antibody during pregnancy. CMV DNA was not detected in the amniotic fluid using a polymerase chain reaction assay. The 65 fetuses, including 3 sets of twins, were followed through birth. CMV DNA was not detected in urine samples obtained within the first 2 weeks of life. In conclusion, CMV DNA was not detected in the amniotic fluid of women who did not have CMV infection. These results, however, suggest that the negative predictive value of prenatal amniotic fluid analysis is high and that the presence of CMV DNA in the amniotic fluid has clinical significance for the diagnosis of congenital CMV infection if detected in pregnant women.