Prediction of Congenital Cytomegalovirus Infection in High-Risk Pregnant Women

Performance evaluation of fully automated cobas® 6800 CMV PCR for the detection and quantification of cytomegalovirus DNA in neonatal urine and saliva, and adult urine, saliva, and vaginal secretion

Laboratory testing for cytomegalovirus (CMV) in bodily fluids is essential to manage congenital and prenatal CMV infection. The rapid and fully automated cobas® CMV PCR is approved only for the testing of plasma in transplant patients. To evaluate the performance of the cobas® CMV to detect and quantify CMV DNA in neonatal and adult female urine, saliva, and vaginal secretion, the limit of detection (LoD), limit of quantification (LoQ), imprecision, linearity, PCR efficiency, bias, analytical specificity, cross-reactivity, and cross-contamination of the cobas® CMV for urine, saliva, and vaginal secretion was determined. The performance of the assay was evaluated prospectively with two laboratory-developed PCR assays using neonatal and adult urine, saliva swabs, and vaginal swabs. The LoD and LoQ were 31 and 100 IU/mL, respectively, for urine, and 81 and 100 IU/mL, respectively, for vaginal secretion. The LoD and LoQ for saliva were the same (200 IU/mL). The cobas® CMV was precise (coefficient of variation ≤10%), linear (R2  ≥ 0.995), and efficient (1.07 and 1.09) between 100 and 250,000 IU/mL for the sample types. The bias and analytical specificity was <±0.30 log10 IU/mL and 100%, respectively. Cross-reactivity with non-CMV pathogens was not detected. Cross-contamination rate was 0.28%. The diagnostic accuracy, sensitivity, and specificity of the cobas® CMV for neonatal urine and saliva were ≥95.0%, ≥93.3%, and ≥90.4%, respectively. The overall percent agreement for adult urine, saliva, and vaginal secretion was 86.6%, 94.5%, and 89.4%, respectively. Taken together, the cobas® CMV demonstrated acceptable analytical and diagnostic performance, and is suitable for routine diagnostic laboratory investigation of CMV infection in neonates and adults.

Detecting human cytomegalovirus in urine, vagina and saliva: Impact of biological fluids and storage durations and temperatures on CMV DNA recovery

Sample collection, transport and storage conditions vary in the human cytomegalovirus (CMV) shedding literature. Currently, limited data exist on the impact of biological fluids and pre-analytical sample handling on the detection of CMV DNA. To evaluate CMV DNA recovery from urine, vaginal fluid and saliva stored in different conditions, adult urine, vaginal and saliva fluids and swabs, stored with or without selected nucleic acid preservation media at various durations and temperatures, was compared by polymerase chain reaction (PCR) quantitation of spiked samples and self-collected urine (n = 45) and vaginal swabs (n = 58) from CMV seropositive pregnant women. There was a time-dependent reduction in CMV DNA recovery from urine, urine diluted in phosphate-buffered saline, and saliva stored at 2-8°C, but not from urine preserved in cobas® PCR transport media (CPM) (urine/CPM). For vaginal fluid, a reduction in recovery was evident after 7 days storage at 2-8°C. CMV DNA recovery over 91 days was similar between -80°C and -20°C storage for urine and vaginal swabs preserved in CPM, and saliva swabs preserved in eNAT® PCR transport media. A statistically significant change in CMV DNA recovery after 25 months storage (median) at -80°C was not observed for self-collected urine/CPM and vaginal swab/CPM from pregnant women. Taken together, recovery of CMV DNA is dependent on fluid type and storage conditions. To improve the validity and reliability of detection at different storage durations and temperatures, the use of nucleic acid preserving transport media at the point of collection for urine, vaginal fluid and saliva may be essential.

Fetal Ultrasound and Magnetic Resonance Imaging Abnormalities in Congenital Cytomegalovirus Infection Associated with and without Fetal Growth Restriction

Congenital cytomegalovirus infection (cCMV) can cause fetal growth restriction (FGR) and severe sequelae in affected infants. Clinicians generally suspect cCMV based on multiple ultrasound (US) findings associated with cCMV. However, no studies have assessed the diagnostic accuracy of fetal US for cCMV-associated abnormalities in FGR. Eight FGR and 10 non-FGR fetuses prenatally diagnosed with cCMV were examined by undergoing periodic detailed US examinations, as well as postnatal physical and imaging examinations. The diagnostic accuracy of prenatal US for cCMV-associated abnormalities was compared between FGR and non-FGR fetuses with cCMV. The diagnostic sensitivity rates of fetal US for cCMV-related abnormalities in FGR vs. non-FGR fetuses were as follows: ventriculomegaly, 66.7% vs. 88.9%; intracranial calcification, 20.0% vs. 20.0%; cysts and pseudocysts in the brain, 0% vs. 0%; ascites, 100.0% vs. 100.0%; hepatomegaly, 40.0% vs. 100.0%; splenomegaly, 0% vs. 0%. The diagnostic sensitivity of fetal US for hepatomegaly and ventriculomegaly in FGR fetuses with cCMV was lower than that in non-FGR fetuses with cCMV. The prevalence of severe long-term sequelae (e.g., bilateral hearing impairment, epilepsy, cerebral palsy, and severe developmental delay) in the CMV-infected fetuses with FGR was higher, albeit non-significantly. Clinicians should keep in mind the possibility of overlooking the symptoms of cCMV in assessing fetuses with FGR.

Noninvasive Prediction of Congenital Cytomegalovirus Infection After Maternal Primary Infection

OBJECTIVE

To develop and internally validate a noninvasive method for the prediction of congenital cytomegalovirus (CMV) infection after primary maternal CMV infection.

METHODS

We conducted a secondary analysis of a multicenter randomized placebo-controlled trial of CMV hyperimmune globulin to prevent congenital infection. Women were eligible if they had primary CMV infection, defined as detectable plasma CMV-specific immunoglobulin (Ig)M and CMV-specific IgG with avidity less than 50% before 24 weeks of gestation or IgG seroconversion before 28 weeks, and were carrying a singleton fetus without ultrasonographic findings suggestive of CMV infection. Antibody assays were performed in a single reference laboratory. Congenital infection was defined as CMV detection in amniotic fluid, neonatal urine or saliva, or postmortem tissue. Using backward elimination, we developed logit models for prediction of congenital infection using factors known at randomization. The performance of the model was assessed using leave-one-out cross-validation (a method of internal validation).

RESULTS

Of 399 women enrolled in the trial, 344 (86%) had informative data for this analysis. Congenital infection occurred in 68 pregnancies (20%). The best performing model included government-assisted insurance, IgM index 4.5 or higher, IgG avidity less than 32%, and whether CMV was detectable by polymerase chain reaction in maternal plasma at the time of randomization. Cross-validation showed an average area under the curve of 0.76 (95% CI 0.70-0.82), indicating moderate discriminatory ability. More parsimonious one-, two-, and three-factor models performed significantly less well than the four-factor model. Examples of prediction with the four-factor model: for a woman with government-assisted insurance, avidity less than 32%, IgM index 4.5 or higher, and detectable plasma CMV, probability of congenital infection was 0.69 (95% CI 0.53-0.82); for a woman with private insurance, avidity 32% or greater, IgM index less than 4.5, and undetectable plasma CMV, probability of infection was 0.03 (95% CI 0.02-0.07).

CONCLUSION

We developed models to predict congenital CMV infection in the presence of primary maternal CMV infection and absence of ultrasonographic findings suggestive of congenital infection. These models may be useful for patient counseling and decision making.

Cytomegalovirus DNA detection in pregnant women with a high IgG avidity index: a valuable tool for diagnosing non-primary infections?

BACKGROUND/AIM

Congenital human cytomegalovirus infection (cCMV) is the commonest congenital infection, and it can result in hearing loss and neurodevelopmental delay. Even if primary infections are more frequent and cause more severe congenital cCMV manifestations compared to NPIs, and despite partial protection from maternal immunity, the highest birth prevalence of cCMV is observed in seropositive women with non-primary CMV infection (NPI). Given that NPI contribute significantly to the overall burden of cCMV, their accurate diagnosis of NPI remains clinically important. Considering that the serological testing for CMV infection is not always reliable, we sought to determine whether detection of CMV DNA in pregnant women with a high IgG avidity index (AI) can help diagnose NPI.

MATERIALS AND METHODS

Human CMV serology screening (IgG, IgM, and IgG AI) was performed for confirmation of CMV infection in serum samples from mainly pregnant women with indications of CMV infection due to IgG⁺ and IgM⁺-positive samples in other laboratories. Pregnant women (or those with termination of pregnancy during the last period) with adequate IgG levels to perform IgG AI were included. Demographic data and mean gestation week at the time of screening were recorded. Serological testing was performed using CE-IVD commercial kits. CMV DNAemia detection by real time PCR (RT-PCR) was applied to confirm suspected CMV infection.

RESULTS

Nine-hundred and thirty-four pregnant women CMV IgG positive with adequate IgG titers for AI testing were included in the study. The percentage of women with a high AI was 71.8% (671/934); among them, nearly 2.4% (16/671) had presence of CMV DNA. Also, 12.4% of women (116/934) had intermediate IgG AI and 15.7% of women (147/934) had low IgG AI. The presence of CMV DNA was observed in 13.8% (16/116) and 39.5% (58/147) of the groups with intermediate and low IgG AI, respectively. A high CMV IgG AI was associated with a negative CMV PCR status (p-value <.00001).

CONCLUSIONS

CMV DNA was present in 2.4% of seropositive women with high IgG AI, indicating active NPI and thus, harboring the risk of cCMV sequelae to the fetus. Moreover, the incidence of NPI may have been underestimated due to single timepoint testing. In order to detect CMV NPI in a seropositive woman, regular and frequent serology testing as well as detection of CMV DNAemia are required which render the whole diagnostic process impractical and not cost-effective.

Characteristics and serology of pregnant women with cytomegalovirus immunoglobulin G seroconversion during pregnancy in Japan

OBJECTIVE

Investigate the characteristics and serology of pregnant women with cytomegalovirus (CMV) immunoglobulin (Ig)G seroconversion during pregnancy to understand the risk factors associated with primary CMV infection and the occurrence of fetal congenital CMV infection.

MATERIALS AND METHODS

We retrospectively studied 3202 pregnant women who were CMV IgG-negative in early pregnancy and were retested for IgG in late pregnancy. Characteristics were compared between participants with and without IgG seroconversion, and serological parameters were compared between participants with and without fetal congenital CMV infection.

RESULTS

Twenty-six participants showed CMV IgG seroconversion and fifteen showed fetal congenital CMV infection. Seroconversion rates were significantly higher in teens (5.0%) than in older women (20s: 0.8%; 30s and over: 0.6%) (p < 0.001). Titers of CMV IgM at IgG seroconversion were higher in women without (median 8.66) than with (median 6.54) congenital infection (p = 0.045). The congenital infection rate was high when IgM titers at IgG seroconversion were low (47.1% with 4.00-12.00 titers and 100% with 1.21-3.99 IgM titers) (p = 0.048).

CONCLUSIONS

Nulliparous pregnant teenagers have a high risk of CMV IgG seroconversion and the CMV IgM titer at IgG seroconversion may help predict the occurrence of fetal congenital CMV infection.

Clinical Diagnostic Testing for Human Cytomegalovirus Infections

Human cytomegalovirus (HCMV) infections are among the most common complications arising in transplant patients, elevating the risk of various complications including loss of graft and death. HCMV infections are also responsible for more congenital infections worldwide than any other agent. Congenital HCMV (cCMV) infections are the leading nongenetic cause of sensorineural hearing loss and a source of significant neurological disabilities in children. While there is overlap in the clinical and laboratory approaches to diagnosis of HCMV infections in these settings, the management, follow-up, treatment, and diagnostic strategies differ considerably. As yet, no country has implemented a universal screening program for cCMV. Here, we summarize the issues, limitations, and application of diagnostic strategies for transplant recipients and congenital infection, including examples of screening programs for congenital HCMV that have been implemented at several centers in Japan, Italy, and the United States.

Recent Approaches and Strategies in the Generation of Anti-human Cytomegalovirus Vaccines

Human cytomegalovirus is the largest human herpesvirus and shares many core features of other herpesviruses such as tightly regulated gene expression during genome replication and latency as well as the establishment of lifelong persistence following infection. In contrast to stereotypic clinical syndromes associated with alpha-herpesvirus infections, almost all primary HCMV infections are asymptomatic and acquired early in life in most populations in the world. Although asymptomatic in most individuals, HCMV is a major cause of disease in hosts with deficits in adaptive and innate immunity such as infants who are infected in utero and allograft recipients following transplantation. Congenital HCMV is a commonly acquired infection in the developing fetus that can result in a number of neurodevelopmental abnormalities. Similarly, HCMV is a major cause of disease in allograft recipients in the immediate and late posttransplant period and is thought to be a major contributor to chronic allograft rejection. Even though HCMV induces robust innate and adaptive immune responses, it also encodes a vast array of immune evasion functions that are thought aid in its persistence. Immune correlates of protective immunity that prevent or modify intrauterine HCMV infection remain incompletely defined but are thought to consist primarily of adaptive responses in the pregnant mother, thus making congenital HCMV a potentially vaccine modifiable disease. Similarly, HCMV infection in allograft recipients is often more severe in recipients without preexisting adaptive immunity to HCMV. Thus, there has been a considerable effort to modify HCMV specific immunity in transplant recipient either through active immunization or passive transfer of adaptive effector functions. Although efforts to develop an efficacious vaccine and/or passive immunotherapy to limit HCMV disease have been underway for nearly six decades, most have met with limited success at best. In contrast to previous efforts, current HCMV vaccine development has relied on observations of unique properties of HCMV in hopes of reproducing immune responses that at a minimum will be similar to that following natural infection. However, more recent findings have suggested that immunity following naturally acquired HCMV infection may have limited protective activity and almost certainly, is not sterilizing. Such observations suggest that either the induction of natural immunity must be specifically tailored to generate protective activity or alternatively, that providing targeted passive immunity to susceptible populations could be prove to be more efficacious.

Cytomegalovirus shedding in seropositive healthy women of reproductive age in Tianjin, China

Cytomegalovirus (CMV) enters latency after primary infection and can reactivate periodically with virus excreted in body fluids which can be called shedding. CMV shedding during the early stage of pregnancy is associated with adverse pregnancy outcome. The shedding pattern in healthy seropositive women who plan to have babies has not been well characterised. Vaginal swabs, urine and blood were collected from 1262 CMV IgG-positive women who intended to have babies and tested for CMV DNA by fluorogenic quantitative PCR method. Serum IgM was also detected. The association between sociodemographic characteristics and CMV shedding prevalence was analysed. Among 1262 seropositive women, 12.8% (161/1262) were detected CMV DNA positive in at least one body fluid. CMV DNA was more frequently detected in vaginal secretion (10.5%) than in urine (3.2%) and blood (0.6%) also with higher viral loads (P < 0.00). CMV shedding was more likely detected in IgM-positive women than IgM-negative women (29.5% (13/44) vs. 12.2% (148/1218); OR 3.03, 95% CI 1.55–5.93; P = 0.001). CMV shedding in vaginal secretion was highly correlated with shedding in urine, the immune state of IgM, the adverse pregnant history and younger age. CMV shedding was more commonly detected in vaginal secretion than in urine or blood with higher viral loads among healthy seropositive women of reproductive age. Further studies are needed to figure out whether the shedding is occasional or continuous and whether it is associated with adverse pregnancy outcomes.

The MRI spectrum of congenital cytomegalovirus infection

Human cytomegalovirus (CMV) is an ubiquitous pathogen, with a high worldwide seroprevalence. When acquired in the prenatal period, congenital CMV (cCMV) is a major cause of neurodevelopmental sequelae and hearing loss. cCMV remains an underdiagnosed condition, with no systematic screening implemented in pregnancy or in the postnatal period. Therefore, imaging takes a prominent role in prenatal diagnosis of cCMV. With the prospect of new viable therapies, accurate and timely diagnosis becomes paramount, as well as identification of fetuses at risk for neurodevelopmental sequelae. Fetal magnetic resonance imaging (MRI) provides a complementary method to ultrasound (US) in fetal brain and body imaging. Anterior temporal lobe lesions are the most specific finding, and MRI is superior to US in their detection. Other findings such as ventriculomegaly, cortical malformations and calcifications, as well as hepatosplenomegaly, liver signal changes and abnormal effusions are unspecific. However, when seen in combination these should raise the suspicion of fetal infection, highlighting the need for a full fetal assessment. Still, some fetuses deemed normal on prenatal imaging are symptomatic at birth or develop delayed cCMV-associated symptoms, leaving room for improvement of diagnostic tools. Advanced MR sequences may help in this field and in determining prognosis, but further studies are needed.

Prevalence of cytomegalovirus DNAemia and genotypic distribution among childbearing mothers and neonates in Taiwan

BACKGROUND

Congenital cytomegalovirus (CMV) infection is the leading cause of neurologic disabilities and sensorineural hearing loss in children. However, in Taiwan, there is limited information on the genotypic diversity and prevalence of perinatal CMV infection in both mothers and neonates. The aim of this study was to screen samples from both mothers and umbilical cord blood for CMV at the time of delivery and to determine the CMV genotypic distribution.

METHODS

Between June 2012 and July 2015, residual maternal and umbilical cord blood samples were collected from consenting participants admitted to the Chang Bing Show Chwan Memorial Hospital in central Taiwan. The blood samples were screened for CMV DNA using real-time PCR assay, and the genotypic classification of the CMV UL55, UL144, and US28 genes was determined by sequencing and phylogenetic analysis.

RESULTS

A total of 1282 mother-neonate paired samples were enrolled in the study, 95.3% of whom were Taiwanese. CMV DNA was detectable in 6.2% of the maternal blood samples, with a significantly higher rate noted in non-Taiwanese mothers (11.7%,p=0.027). For the 1,282 umbilical cord blood samples, CMV DNA was detectable in 5.3% of the samples. The presence of CMV DNA in maternal blood was positively associated with the presence of CMV DNA in umbilical cord blood (p=0.01). In addition, the UL55, UL144, and US28 genotypic distribution was similar between mothers and neonates.

CONCLUSION

The prevalence of CMV DNAemia in childbearing mothers and neonates is similar and their genotypic distribution implies potential CMV infection during pregnancy.

Diagnostic Value of Cytomegalovirus IgM Antibodies at Birth in PCR-Confirmed Congenital Cytomegalovirus Infection

Although cytomegalovirus (CMV) DNA detection in urine is the standard method for diagnosing congenital cytomegalovirus infection (CCMVI), polymerase chain reaction (PCR) is not comprehensively available. Currently, the efficacy of CMV-specific IgM (CMV-IgM) and CMV-specific IgG (CMV-IgG) detection remains unclear. To determine the sensitivity and specificity of CMV-specific antibodies at birth, we investigated CMV-IgM and CMV-IgG titers in CCMVI cases and non-CCMVI controls, with confirmed diagnoses by urine quantitative real-time PCR within 3 weeks after birth. We included 174 infants with suspected CCMVI in whom serological testing was performed within the first 2 weeks after birth during 2012–2018. We classified the participants into a CCMVI group (n = 32) and non-CCMVI group (n = 142) based on their urine PCR results. The CMV-IgM-positive rate was 27/32 (84.4%) in the CCMVI group, compared with 1/142 (0.7%) in the non-CCMVI group (p < 0.0001). The positive CMV-IgG rates were 32/32 (100%) in the CCMVI group and 141/142 (99.3%) in the non-CCMVI group. The positive predictive value for CMV-IgM was high at 96.4% (27/28). This value may be sufficient for clinical use, especially in settings with limited resources where PCR is unavailable. However, CCMVI screening by CMV-IgM alone appears insufficient because of the considerable number of false-negative cases.

Serological screening of immunoglobulin M and immunoglobulin G during pregnancy for predicting congenital cytomegalovirus infection

Background

Cytomegalovirus (CMV) is one of the most frequent pathogens for congenital infections. Most cases of congenital CMV infection (cCMV) are asymptomatic at birth, but sensorineural hearing loss (SNHL) or neurodevelopmental delay can appear later in childhood. This prospective study examined the practicability of serological screening for anti-CMV immunoglobulin (Ig) G and anti-CMV IgM in pregnant women.

Methods

A total of 11,753 pregnant women were examined for CMV IgG and CMV IgM during the first or second trimester. When IgM was positive, IgG was reevaluated more than two weeks later. When IgG was negative, IgG was reevaluated in the second or third trimester. All neonates from mothers with positive/borderline IgM or IgG seroconversion underwent polymerase chain reaction assay for CMV using urine samples to diagnose cCMV. Levels of IgG and IgM were compared between mothers with and without cCMV. Receiver operating characteristic (ROC) curves for IgM titers were analyzed.

Results

Eight of 500 neonates (1.6%) born from mothers with positive IgG and positive IgM, and 3 of 13 neonates (23.1%) born from mothers with IgG seroconversion were diagnosed with cCMV. Neither IgM titers nor IgG titers differed significantly between cCMV and non-cCMV groups. The area under the ROC curve was 0.716 and the optimal cut-off for IgM was 7.28 index (sensitivity = 0.625, specificity = 0.965, positive predictive value = 0.238, negative predictive value = 0.993). Titers of IgG were not frequently elevated in pregnant women with positive IgM during the observation period, including in those with cCMV. All 11 cCMV cases were asymptomatic at birth and none had shown SNHL or developmental delay as of the last regular visit (mean age, 40 months).

Conclusions

Seroconversion of CMV IgG and high-titer IgM during early pregnancy are predictors of cCMV. High IgM titer (> 7.28 index) is a predictor despite relatively low sensitivity. Levels of IgG had already plateaued at first evaluation in mothers with cCMV. Maternal screening offered insufficient positive predictive value for diagnosing cCMV, but allowed identifying asymptomatic cCMV cases in an early stage.

Risk factors associated with the vertical transmission of cytomegalovirus in seropositive pregnant women

Congenital cytomegalovirus infection (cCMV) is the leading cause of childhood disabilities. More recent data indicates that cCMV following maternal nonprimary infection occurs frequently and can cause similar rates of sequelae as those following maternal primary infection. However, the risks associated with cCMV especially in CMV-seropositive women remain unclear. This review summarizes potential risk factors of cCMV in seropositive women with perspectives on the causal link including sociodemographic factors, virological characteristics, the host immune system, genomics, metabonomics and proteomics. These observations and some new molecular markers, although not yet validated as a reliable tool predictive of cCMV, could be the basis for designing future prospective studies.

Maternal and neonatal screening methods for congenital cytomegalovirus infection

Human cytomegalovirus (CMV) is a common cause of congenital infection that may lead to severe long-term sequelae. Because there are no established vaccines, fetal interventions or neonatal treatments, neither maternal nor neonatal screening is recommended. However, recent studies have indicated that early antiviral treatment may improve neurological outcomes in symptomatic infants with congenital infection. Therefore, prenatal detection may be important in newborns at high risk of such infection. Polymerase chain reaction for CMV DNA in the amniotic fluid is considered the gold standard for diagnosis of intrauterine infection, but its use is limited because amniocentesis is an invasive procedure. In a prospective cohort study, we have reported that the presence of CMV DNA in secretions of the maternal uterine cervix were predictive of congenital infection in groups at high risk. However, we also recently demonstrated that maternal serological screening for primary CMV infection using specific immunoglobulin G, the immunoglobulin G avidity index or specific immunoglobulin M can overlook many cases. Previous research has indicated that the combination of early detection by universal neonatal screening of urinary CMV DNA combined with early antiviral therapy can improve outcomes in infants with symptomatic congenital infection. In this article, we review the current state of maternal and neonatal screening for congenital CMV infection.

Potential Biomarkers for Predicting Congenital Cytomegalovirus Infection

Early diagnosis and treatment of infants with symptomatic congenital cytomegalovirus (CMV) infection may improve neurological outcomes. For this reason, prenatal detection of newborns at high risk for congenital CMV infection is important. A polymerase chain reaction (PCR) assay for CMV DNA in the amniotic fluid is the gold standard for the diagnosis of intrauterine CMV infection; however, amniocentesis is an invasive procedure. Recently, we have found that the presence of CMV DNA in the maternal uterine cervical secretion is predictive of the occurrence of congenital CMV infection in CMV immunoglobulin M (IgM)-positive pregnant women. In contrast, we have suggested that maternal serological screening for primary CMV infection using CMV-specific immunoglobulin G (IgG), the IgG avidity index, or CMV-specific IgM overlooks a number of newborns with congenital CMV infection. We will review current knowledge of the potential biomarkers for predicting congenital CMV infection.

Universal Screening With Use of Immunoglobulin G Avidity for Congenital Cytomegalovirus Infection

Background

The aim of this prospective cohort study was to evaluate the efficacy of maternal screening for congenital cytomegalovirus infection (CCI) using cytomegalovirus (CMV) immunoglobulin G (IgG) and the IgG avidity index (AI).

Methods

Pregnant women underwent screening of CMV IgG and AI measurements. IgG-negative women underwent remeasurement of IgG after educational intervention. Women with an AI ≤45% received further examinations, including measurement of CMV IgM. All newborns received polymerase chain reaction analyses of the urine, and CCI was diagnosed by the detection of CMV-DNA in the urine. Primary infection was defined as an AI <35% and/or positive IgM (>1.20 index). Serum samples from women with an AI >45% were stored, and the IgM levels were measured after delivery. The efficacy of AI and IgM for CCI screening was compared.

Results

A total of 1562 (71.2%) women tested positive for IgG. In this study, 10 newborns with CCI were detected. The presence of infection in 3 newborns from mothers with primary infection was predicted by screening of IgG and AI <35%. However, infection in 7 newborns from women with nonprimary infection could not be predicted by screening of CMV IgG, AI <35%, or IgM. The application of an AI <35% for CCI screening yielded 22.2% sensitivity, 95.0% specificity, 2.5% positive predictive value, and 99.5% negative predictive value and was similar to that of IgM (11.1% sensitivity, 93.2% specificity, 0.9% positive predictive value, and 92.7% negative predictive value).

Conclusions

Maternal screening using CMV IgG and AI can identify pregnancies with CCI from primary infection, but overlooks a number of those from nonprimary infection.

Clinical factor associated with congenital cytomegalovirus infection in pregnant women with non-primary infection

The aim of this nested case-control study was to evaluate clinical factors associated with the occurrence of congenital cytomegalovirus (CMV) infection in pregnant women with non-primary CMV infection. In a cohort study of CMV screening for 2193 pregnant women and their newborns, seven newborns with congenital CMV infection were identified among 1287 pregnant women with non-primary CMV infection that was defined as negative IgM and positive IgG with IgG avidity index >45%. In the 1287 women with non-primary CMV infection, clinical findings and complications were compared between pregnancies with and without congenital CMV infection. Clinical factors associated with the occurrence of congenital CMV infection were evaluated. The birth weight of newborns with congenital CMV infection was less than that of newborns without congenital infection (p < 0.05). Univariate logistic regression analyses demonstrated that threatened premature delivery (OR 10.6, 95%CI 2.0-55.0; p < 0.01) and multiple pregnancy (OR 7.1, 95%CI 1.4-37.4; p < 0.05) were associated with congenital infection. Multivariable logistic regression analyses demonstrated that threatened premature delivery (OR 8.4, 95%CI 1.5-48.1; p < 0.05) was a single risk factor for congenital CMV infection in pregnant women with non-primary CMV infection. This study revealed for the first time that threatened premature delivery was associated with the occurrence of congenital CMV infection in pregnant women with non-primary CMV infection, the pathophysiology of which may be closely associated with CMV reactivation during pregnancy.

Anti-cytomegalovirus immunoglobulin M titer for congenital infection in first-trimester pregnancy with primary infection: a multicenter prospective cohort study

OBJECTIVE

We evaluated cytomegalovirus (CMV) immunoglobulin M (IgM) titer in pregnant women with primary infection as a predictive factor for congenital infection.

STUDY DESIGN

Maternal CMV antibody screening during the first trimester was conducted prospectively at 16 centers in Japan between September 2013 and 2015. Women with confirmed maternal primary infection underwent testing for fetal congenital infection, and we investigated the positive predictive value of CMV IgM titer levels for congenital infection in women with a low IgG avidity.

RESULTS

We identified 6 (8.6%) cases of congenital infection among 70 pregnant women with positive/borderline IgG, positive IgM and IgG avidity index ⩽35.0% and 11 (39.3%) among 28 women with IgG and/or IgM seroconversion. IgM titer level ⩾6.00 index showed the highest positive predictive value (17.1%).

CONCLUSION

High titer of CMV IgM during the first trimester in pregnant women with primary infection is a risk factor for congenital infection.