Prenatal diagnosis of fetal cytomegalovirus infection

Detection and Prevention of Perinatal Infection: Cytomegalovirus and Zika Virus

Congenital cytomegalovirus is the most common viral congenital infection, and affects up to 2% of neonates. Significant sequelae may develop after congenital cytomegalovirus, including hearing loss, cognitive defects, seizures, and death. Zika virus is an emerging virus with perinatal implications; a congenital Zika virus syndrome has been identified, and includes findings such as microcephaly, fetal nervous system abnormalities, and neurologic sequelae after birth. Screening, diagnosis, prevention, and treatment of these perinatal infections are reviewed in this article.

Seroprevalence of Cytomegalovirus among pregnant women and hospitalized children in Palestine

Background

Human Cytomegalovirus (HCMV) is the most common cause of congenital infections. The maternal immune status plays a major role in the likelihood of congenital infection. The aim of this study is to shed light on the seroprevalence of HCMV in pregnant women, hospitalized children and newborns including cases of congenital infections in Palestine.

Methods

We analyzed HCMV IgG and IgM test results that had been ordered for pregnant women, hospitalized children and newborns in the years 2006–2012 at Al-Makassed Islamic Charitable Hospital (MICH) in East Jerusalem. Furthermore, we reviewed the medical charts of newborns and HCMV IgM-positive children.

Results

HCMV IgG was positive in 96.6% of pregnant women, in 88% of hospitalized children and in 98.4% of hospitalized newborns. HCMV IgM was positive in 11.5% of pregnant women, in 11.7% of hospitalized children and in 2% of hospitalized newborns respectively. The HCMV avidity assay revealed that 95% of IgM-positive pregnant women had high avidity (>60%) indicating that most Palestinian women were undergoing a recurrent HCMV infection. Real time PCR on limited number of cases indicated that 62.5% of infants, mostly born to IgM-positive mothers and 83.3% of HCMV IgM-positive children had detectable HCMV DNA in their urine. Out of the 249 newborns tested during this study period, four (1.6%) were subjected to Gancyclovir treatment because of symptomatic congenital HCMV infection.

Conclusions

This is the first report to provide an insight into HCMV seroprevalence in Palestine. Despite the high rate of seropositivity, the importance of HCMV testing during pregnancy should not be underestimated. A comprehensive study with a long term follow-up examination of offspring born to HCMV IgM-positive mothers would be required to provide estimates of an accurate percentage of symptomatic congenital HCMV infection in Palestine.

Review of cytomegalovirus seroprevalence and demographic characteristics associated with infection

Cytomegalovirus establishes a lifelong latent infection following primary infection that can periodically reactivate with shedding of infectious virus. Primary infection, reactivation and reinfection during pregnancy can all lead to in utero transmission to the developing fetus. Congenital CMV infections are a major cause of permanent hearing loss and neurological impairment. In this literature review, we found that CMV infection was relatively common among women of reproductive age, with seroprevalence ranging from 45 to 100%. CMV seroprevalence tended to be highest in South America, Africa and Asia and lowest in Western Europe and United States. Within the United States, CMV seroprevalence showed substantial geographic variation as well, differing by as much as 30 percentage points between states, though differences might be explained by variation in the types of populations sampled. Worldwide, seroprevalence among non-whites tended to be 20-30 percentage points higher than that of whites (summary prevalence ratio (PR) = 1.59, 95% confidence interval (CI) = 1.57-1.61). Females generally had higher seroprevalences than males, although in most studies the differences were small (summary PR = 1.13, 95% CI = 1.11-1.14). Persons of lower socioeconomic status were more likely to be CMV seropositive (summary PR = 1.33, 95% CI = 1.32-1.35). Despite high seroprevalences in some populations, a substantial percentage of women of reproductive age are CMV seronegative and thus at risk of primary CMV infection during pregnancy. Future vaccine or educational campaigns to prevent primary infection in pregnant women may need to be tailored to suit the needs of different populations.

[Congenital cytomegalovirus infection: is serological screening during pregnancy necessary?]

Primary cytomegalovirus (CMV) infection occurs during pregnancy in 1% to 4% of seronegative women and may be transmitted to the fetus in up to 40% of cases. Up to 10% of intrauterine CMV infections result in symptomatic congenital disease at birth. Half of these children and 13% of those born with asymptomatic infection will develop significant clinical sequelae in infancy, especially sensorineural hearing loss. Routine CMV screening during pregnancy is not recommended in Spain owing to the absence of an effective CMV vaccine, the lack of preventive measures or therapy during pregnancy, the difficulty in diagnosing a reactivated infection, and the possibility of symptomatic congenital infections in children of immune women. However, sensitive and specific methods to diagnose primary maternal and fetal infection now exist, and new preventive and therapeutic measures have been developed. Currently, these procedures are not universally available and need to be tested in larger trials. Furthermore, the prevalence of seropositive status in pregnant women, the frequency of congenital infection, and the percentage of infants born with hearing impairment and mental retardation in our country are not known. Therefore, it would not be appropriate to introduce routine screening for CMV in pregnancy at the present time. However, increased efforts should be made to inform women about congenital CMV disease, to develop the diagnosis of fetal infection and methods to determine the extent of involvement in the case of suggestive ultrasound findings, and to treat symptomatic infected newborns with antivirals to reduce hearing impairment.

The prognostic value of ultrasound abnormalities and biological parameters in blood of fetuses infected with cytomegalovirus

OBJECTIVE

To evaluate the prognostic value of ultrasound abnormalities and of selected biological parameters in blood of fetuses infected with cytomegalovirus (CMV).

DESIGN

Retrospective observational study.

SETTING

Two fetal medicine units in Paris, France.

POPULATION

All fetuses infected with CMV referred between 1998 and 2006.

METHODS

We retrospectively analysed data collected prospectively in 73 fetuses infected by CMV with a positive CMV polymerase chain reaction in amniotic fluid. Fetal blood sampling (FBS) was performed for evaluation of platelet count, plasma levels of aminotransferases and gamma-glutamyl transpeptidases (GGT), presence of viraemia and specific fetal immunoglobulin M. Targeted ultrasound examination was performed every fortnight. Ultrasound findings were categorised into normal examination and any ultrasound abnormality, which was further grouped as ultrasound abnormality of the fetal brain and noncerebral ultrasound abnormality.

MAIN OUTCOME MEASURES

A combination of histological findings after termination of pregnancy and evidence of cytomegalic inclusion disease at birth when pregnancies were continued. Clinical symptoms at birth or histological lesions attributable to CMV were considered as poor outcome. Statistical analysis was conducted to determine the value of each parameter to predict outcome. Logistic regression was used to build up a multivariate model combining the relevant parameters.

RESULTS

In univariate analysis, only thrombocytopenia and the presence of any ultrasound abnormality were associated with a poor outcome (P < 10(-4) for both abnormalities). In the multivariate analysis, both thrombocytopenia and the presence of ultrasound abnormalities remained significant independent predictors of a poor outcome. Based on univariate logistic regression, odds ratio for a poor outcome were 1.24, 7.2, 22.5 and 25.5 for each 10,000/mm(3) decrease in platelet count, the presence of noncerebral, any ultrasound and cerebral ultrasound abnormalities, respectively.

CONCLUSIONS

The prognosis of CMV-infected fetuses relies independently on both targeted ultrasound examination and fetal platelet count. FBS for platelet count may therefore justify FBS in infected fetuses even in the absence of ultrasound. features of brain involvement.

Review and meta-analysis of the epidemiology of congenital cytomegalovirus (CMV) infection

We reviewed studies that reported results of systematic cytomegalovirus (CMV) screening on fetuses and/or live-born infants. The overall birth prevalence of congenital CMV infection was 0.64%, but varied considerably among different study populations. About 11% of live-born infants with congenital CMV infection were symptomatic, but the inter-study differences in definitions of symptomatic cases limit the interpretation of these data. Non-white race, low socioeconomic status (SES), premature birth, and neonatal intensive care unit admittance were risk factors for congenital CMV infection. Birth prevalence increased with maternal CMV seroprevalence. Maternal seroprevalence accounted for 29% of the variance in birth prevalence between study populations. Maternal seroprevalence and birth prevalence were both higher in study populations that were ascertained at birth rather than in the prenatal period. Thus, timing of ascertainment should be considered when interpreting birth prevalence estimates. Birth prevalence was inversely correlated with mean maternal age, but this relationship was not significant when controlling for maternal seroprevalence. The rate of transmission to infants born to mothers who had a primary infection or a recurrent infection during pregnancy was 32% and 1.4%, respectively. Possible maternal primary infections (i.e. seropositive mother with CMV IgM) resulted in congenital infections about 20% of the time, but are likely to represent a mixture of primary and recurrent infections. In summary, CMV is a common congenital infection worldwide that can lead to permanent disabilities. There is an urgent need for interventions that can reduce the substantial burden of this often overlooked disease.

Human herpes viruses in pregnancy: cytomegalovirus, Epstein-Barr virus, and varicella zoster virus

Viruses of the human herpesvirus family can have profound effects on pregnancy. Primary maternal infection with cytomegalovirus (CMV) and varicella during pregnancy has been associated with fetal abnormalities and neonatal disease. Public awareness of the role of cytomegalovirus in the etiology of developmental disorders and chronic disabilities needs to increase. With time, we may see new interventions for treatment of infected pregnant women and prevention of long-term effects. Attention must be focused on development of a safe and effective vaccine. With the introduction of an efficacious varicella vaccine, the rate of varicella in pregnancy is expected to decrease dramatically. Physicians caring for women have the opportunity to prevent the complications of varicella by identifying and vaccinating susceptible women.

Requirements for diagnosis of prenatal cytomegalovirus infection by amniotic fluid culture

BACKGROUND

Amniotic fluid culture is considered to be the best method for the detection of antenatal cytomegalovirus (CMV) infection and prediction of congenital CMV infection. Recently, however, some false-negative results have been reported.

OBJECTIVES

Prediction of congenital CMV infection by amniotic fluid culture with emphasis on false-negative results.

STUDY DESIGN

Retrospective study of 42 pregnant women with primary CMV infection. First, estimation of seroconversion related to the gestational age was established. Afterwards, results of amniotic fluid culture were compared either with CMV isolation from biopsies from aborted fetuses, or with viral culture of newborns' urine.

RESULTS

In 18 cases (43%), amniotic fluid culture gave negative results which coincided with 18 uninfected newborns. In 18 other cases (43%), amniotic fluid culture was positive for CMV: 7 newborns with CMV viruria and 11 terminations of pregnancy with CMV isolated from fetal biopsies. In the remaining 6 cases, amniotic fluid culture gave negative results, whereas the 6 newborns were all infected.

CONCLUSION

Amniotic fluid culture remains an accurate method for the diagnosis of CMV antenatal infection. However, in order to avoid false-negative results, the importance of a correct estimation of the gestational age of seroconversion and of a sufficient interval between primary infection and amniocentesis are stressed.

Routine CMV screening during pregnancy

Cytomegalovirus (CMV) screening during pregnancy has been widely discussed for several years, but still no consensus has been agreed. With a number of live births of 750,000 per year in France, we would expect 7500 infected infants at birth per year (rate of congenital infection of 1%). Among infected infants at birth, the number of severely infected foetuses would be approximately 75, the number of infants with severe sequelae would be 480, 675 approximately would present with hearing loss and the number of asymptomatic infants would be 6270. Five different preventive methods for congenital CMV infection are possible: (1) Routine CMV screening at the beginning of pregnancy for primary prevention. (2) Secondary prevention by antenatal diagnosis of congenital CMV infection complications. (3) Tertiary prevention by serological testing during pregnancy. (4) Tertiary prevention by serological screening at birth. (5) Tertiary prevention: Hearing loss screening at birth. The aims of this review are to define the advantages and disadvantages of these different methods of CMV screening during pregnancy and to determine if the current available information would make systematic testing acceptable.

Hyperechogenic fetal bowel: a large French collaborative study of 682 cases

Hyperechogenic fetal bowel is detected in 0.1-1.8% of pregnancies during the second or third trimester. This ultrasound sign is associated with cystic fibrosis or other conditions (e.g., chromosomal anomalies, viral infection) but no large-scale prospective studies have been conducted. This 1997-1998 multicenter study in 22 molecular biology laboratories identified 682 cases of hyperechogenic fetal bowel detected by routine ultrasound examination during the second (86%) or third trimester. The fetal bowel was considered hyperechogenic when its echogenicity was broadly similar to, or greater than, that of the surrounding bone. Karyotyping, screening for viral infection, and screening for cystic fibrosis mutations were performed in all cases. Pregnancy outcome and postnatal follow-up were obtained in 656 of the 682 cases (91%). In 447 cases (65.5%), a normal birth was observed. Multiple malformations were observed in 47 cases (6.9%), a significant chromosomal anomaly was noted in 24 (3.5%), cystic fibrosis in 20 (3%), and viral infection in 19 (2.8%). In utero unexplained fetal death occurred in 1.9% of cases, toxemia in 1.2%, IUGR in 4.1%, and premature birth in 6.2%. This study demonstrates that this ultrasound sign is potentially associated with medically significant outcomes. Having established that the bowel is hyperechogenic, recommended investigations should include a detailed scan with Doppler measurements, fetal karyotyping, cystic fibrosis screening, and infectious disease screening. After birth, newborns require pediatric examination because a surgical treatment may be necessary. This should be combined with clear counseling of the parents.

Prenatal testing for infectious disease

Prenatal testing for infectious diseases is performed frequently and for a variety of indications. The purpose of this article is to review the maternal and fetal infections that pose diagnostic concerns. Recent advances in diagnostic testing (such as avidity testing) is included. Testing issues focus on the diagnosis of maternal and fetal infection.

Diagnosis and management of human cytomegalovirus infection in the mother, fetus, and newborn infant

Human cytomegalovirus (HCMV) is the leading cause of congenital viral infection and mental retardation. HCMV infection, while causing asymptomatic infections in most immunocompetent subjects, can be transmitted during pregnancy from the mother with primary (and also recurrent) infection to the fetus. Hence, careful diagnosis of primary infection is required in the pregnant woman based on the most sensitive serologic assays (immunoglobulin M [IgM] and IgG avidity assays) and conventional virologic and molecular procedures for virus detection in blood. Maternal prognostic markers of fetal infection are still under investigation. If primary infection is diagnosed in a timely manner, prenatal diagnosis can be offered, including the search for virus and virus components in fetal blood and amniotic fluid, with fetal prognostic markers of HCMV disease still to be defined. However, the final step for definite diagnosis of congenital HCMV infection is detection of virus in the blood or urine in the first 1 to 2 weeks of life. To date, treatment of congenital infection with antiviral drugs is only palliative both prior to and after birth, whereas the only efficacious preventive measure seems to be the development of a safe and immunogenic vaccine, including recombinant, subunit, DNA, and peptide-based vaccines now under investigation. The following controversial issues are discussed in the light of the most recent advances in the field: the actual perception of the problem; universal serologic screening before pregnancy; the impact of correct counseling on decision making by the couple involved; the role of prenatal diagnosis in ascertaining transmission of virus to the fetus; the impact of preconceptional and periconceptional infections on the prevalence of congenital infection; and the prevalence of congenitally infected babies born to mothers who were immune prior to pregnancy compared to the number born to mothers undergoing primary infection during pregnancy.

Diagnosis and management of human cytomegalovirus infection in the mother, fetus, and newborn infant

Human cytomegalovirus (HCMV) is the leading cause of congenital viral infection and mental retardation. HCMV infection, while causing asymptomatic infections in most immunocompetent subjects, can be transmitted during pregnancy from the mother with primary (and also recurrent) infection to the fetus. Hence, careful diagnosis of primary infection is required in the pregnant woman based on the most sensitive serologic assays (immunoglobulin M [IgM] and IgG avidity assays) and conventional virologic and molecular procedures for virus detection in blood. Maternal prognostic markers of fetal infection are still under investigation. If primary infection is diagnosed in a timely manner, prenatal diagnosis can be offered, including the search for virus and virus components in fetal blood and amniotic fluid, with fetal prognostic markers of HCMV disease still to be defined. However, the final step for definite diagnosis of congenital HCMV infection is detection of virus in the blood or urine in the first 1 to 2 weeks of life. To date, treatment of congenital infection with antiviral drugs is only palliative both prior to and after birth, whereas the only efficacious preventive measure seems to be the development of a safe and immunogenic vaccine, including recombinant, subunit, DNA, and peptide-based vaccines now under investigation. The following controversial issues are discussed in the light of the most recent advances in the field: the actual perception of the problem; universal serologic screening before pregnancy; the impact of correct counseling on decision making by the couple involved; the role of prenatal diagnosis in ascertaining transmission of virus to the fetus; the impact of preconceptional and periconceptional infections on the prevalence of congenital infection; and the prevalence of congenitally infected babies born to mothers who were immune prior to pregnancy compared to the number born to mothers undergoing primary infection during pregnancy.

Prenatal diagnosis of congenital cytomegalovirus infection by detection of immunoglobulin M antibodies to the 70-kd heat shock protein in fetal serum

OBJECTIVE

Antibodies to the 70-kd heat shock protein were evaluated as biomarkers for cytomegalovirus infection.

STUDY DESIGN

Fetal sera that was obtained by cordocentesis at 22 to 25 weeks of gestation from 53 mothers with a confirmed primary cytomegalovirus infection and 28 mothers (control group) without cytomegalovirus infection who had been screened for Rh incompatibility, were assayed by enzyme-linked immunosorbent assay for immunoglobulin M and G anti-70-kd heat shock protein antibodies.

RESULTS

Eighteen of 53 fetuses (34.0%) from cytomegalovirus-positive mothers were infected, which was determined by culture or polymerase chain reaction. Anti-70-kd heat shock protein immunoglobulin M was detected in 17 of 18 sera (94.4%) from cytomegalovirus-infected fetuses, in 3 of 35 sera (8.6%) from uninfected fetuses, and in 0 of 28 sera from the control group (P <.0001). The level of antibody reactivity was correlated positively with fetal disease. Anti-70-kd heat shock protein immunoglobulin G was detected in sera from 52 of 53 fetuses (98.1%) from cytomegalovirus-infected mothers.

CONCLUSION

The anti-70-kd heat shock protein immunoglobulin M assay may be of value in the assessment of fetal cytomegalovirus infection in pregnant women with a primary cytomegalovirus infection.

Congenital cytomegalovirus infection: review of the epidemiology and outcome

Cytomegalovirus (CMV) is one of the most common viral causes of congenital infection. A future decision to lower its incidence by vaccination will depend on epidemiological conditions within a country and on the safety of the vaccine to be used, because a life vaccine may cause latency and subsequent reactivation that still may harm the fetus. The aim was to review the epidemiological studies published so far, with respect to factors that affect the incidence of congenital CMV infection, and factors that may influence its outcome, such as preexisting maternal immunity. The study included the data of 19 studies that were retrieved from a MEDLINE search during the period 1977 to 1997. The incidence of congenital CMV infection varied between 0.15% and 2.0% and seemed to correlate with the level of preexisting immunity in the population. Although preexisting maternal immunity was reported to strongly reduce transmission, the severity of congenital CMV infection (symptoms at birth and or sequelae later in life) was not significantly greater after virus transmission due to a primary infection of the mother as compared with recurrence or reinfection. The data indicate that preexisting immunity of the mother does not significantly mitigate the outcome of congenital infection. Moreover, life vaccines may bear a serious risk when transmittable to the fetus.

TARGET AUDIENCE

Obstetricians and Gynecologists, Family Physicians.

LEARNING OBJECTIVES

After completion of this article, the reader will be able to describe the natural course of a CMV infection, to list the potential sequelae of a congenital CMV infection, to outline potential strategies to prevent transmission of CMV, and to summarize the diagnostic work up of a patient with a potential CMV infection.

Prenatal diagnosis of congenital cytomegalovirus infection in 189 pregnancies with known outcome

Prenatal diagnosis (PD) of fetal cytomegalovirus (CMV) infection was performed in 242 pregnancies, with known outcome in 189 cases. In 141/189 pregnancies, PD was carried out on account of suspicious maternal CMV serology up to gestational week (WG) 23, and in 48 cases on account of abnormal ultrasonic findings detected between WG 18 and 39. Chorionic villus samples (n = 6), amniotic fluid (AF, n = 176) and/or fetal blood specimens (n = 80) were investigated for detection of virus by cell culture, shell vial assay, PCR and/or CMV-specific IgM antibodies. Of 189 fetuses correctly evaluated by CMV detection either in fetal tissue following therapeutic abortion/stillbirth (n = 24) or in urine of neonates within the first 2 weeks of life (n = 33), 57 were congenitally infected. In women with proven or suspected primary infection, the intrauterine transmission rates were 20.6% (7/34) and 24.4% (10/41), respectively. Of the congenitally infected live-born infants, 57.6% (19/33) had symptoms of varying degree. The overall sensitivity of PD in the serologic and ultrasound risk groups was 89.5% (51/57). A sensitivity of 100% was achieved by combining detection of CMV-DNA and CMV-specific IgM in fetal blood or by combined testing of AF and fetal blood for CMV-DNA or IgM antibodies. There was no instance of intrauterine death following the invasive procedure. The predictive value of PD for fetal infection was 95.7% (132/138) for negative results and 100% (51/51) for positive results. Correct results for congenital CMV infection by testing AF samples can be expected with samples obtained after WG 21 and after a time interval of at least 6 weeks between first diagnosis of maternal infection and PD. In case of negative findings in AF or fetal blood and the absence of ultrasound abnormalities at WG 22-23, fetal infection and neonatal disease could be excluded with high confidence. Positive findings for CMV infection in AF and/or fetal blood in combination with CMV suspicious ultrasound abnormalities predicted a high risk of cytomegalic inclusion disease (CID). Furthermore, detection of specific IgM antibodies in fetal blood was significantly correlated with severe outcome for the fetus or the newborn (p = 0.0224). However, normal ultrasound of infected fetuses at WG 22-23 can neither completely exclude an abnormal ultrasound at a later WG and the birth of a severely damaged child nor the birth of neonates which are afflicted by single manifestations at birth or later and of the kind which are not detectable by currently available ultrasonographic techniques.

Prenatal diagnosis of congenital cytomegalovirus infection

OBJECTIVE

To assess prospectively the diagnostic reliability and prognostic significance of prenatal diagnosis of cytomegalovirus (CMV) infection.

METHODS

One hundred ten pregnant women (four with twin pregnancies) with a risk of congenital CMV infection were investigated. Prenatal diagnosis was carried out by amniocentesis and fetal blood sampling (n = 75) or amniocentesis alone (n = 35). Serial ultrasonographic examinations were performed from time of referral until pregnancy end. All infected neonates were given long-term follow-up. Autopsy was performed in all cases of termination of pregnancy.

RESULTS

Nearly 23% (26 of 114) of fetuses were infected and prenatal diagnosis was positive in 20 cases. Sensitivity of prenatal diagnosis was 77% and specificity 100%. In eight cases, parents requested termination of pregnancy on the basis of abnormal ultrasonographic findings and/or biologic abnormalities in fetal blood. In 12 cases, parents decided to proceed with the pregnancy. In this group, one intrauterine and one neonatal death were observed. In one case, prenatal diagnosis revealed an abnormal cerebral sonography and the infant had bilateral hearing loss at birth. In 15 cases (nine positive and six false-negative prenatal diagnoses), no apparent lesion was present at birth, nor did it develop during the follow-up period (mean 31 months). In 88 (77.2%) of 114 infants, no evidence of vertical transmission was found during the pre- or postnatal period.

CONCLUSION

Prenatal diagnosis provides the optimal means for both diagnosing fetal infection (amniocentesis) and identifying fetuses at risk of severe sequelae (ultrasound examination, fetal blood sampling), thus allowing proper counseling.

Screening and diagnosis of congenital cytomegalovirus infection: a 5-y study

Although cytomegalovirus infection is the most common infection transmitted via the placenta, there are no guidelines for routine screening to detect children congenitally infected with cytomegalovirus. From 1993 to 1997, maternal serum and cord vein blood of newborns was screened for HCMV-IgM (n = 21,183). Urine was examined for HCMV-excretion during the first postnatal week to prove HCMV infection in children who expressed HCMV-IgM in cord vein blood (n = 13) or who were born to mothers positive for HCMV-IgM in the serum (n = 234), or when both cord vein blood and maternal serum were positive for HCMV-IgM (n = 6). Congenital HCMV infection was detected in 17 newborns. To determine the incidence of congenital HCMV infection, only those mother/child pairs were selected in whom serum and cord vein blood were investigated (n = 5967 mother/child pairs). In this group 13 newborns were infected. The observed incidence for congenital HCMV infection is 0.21%. It is concluded that that this screening programme will detect those children at risk for congenital HCMV infection. These children have to be examined for virus excretion in the urine. Although the observed incidence is only 0.21%, congenital HCMV infection is a problem that can no longer be neglected because of its long-term sequelae.

Prenatal indicators of congenital cytomegalovirus infection

OBJECTIVE

To assess the validity of a diagnostic protocol designed to predict the outcome of newborns of mothers suspected to have primary cytomegalovirus (CMV) infection during the first 4 months of pregnancy.

STUDY DESIGN

Anti-CMV immunoglobulin (Ig) M detection by enzyme immunoassay and immunoblot together with the determination of anti-CMV IgG avidity allowed us to classify 456 women as (1) uninfected, (2) undergoing either a primary or a recurrent infection, or (3) having an undefined serologic condition. Prenatal diagnosis was carried out at 21 to 23 weeks' gestation for women. The presence of the virus in the amniotic fluid was determined by culture, polymerase chain reaction, and quantitative polymerase chain reaction. Macroscopic and histologic examinations were undertaken on tissue from aborted fetuses, whereas for newborns culture was performed on urine sampled during the first week of life.

RESULTS

Congenital infections were found exclusively among women undergoing a primary infection. The quantitative determination of CMV DNA in the amniotic fluid of at least 10(3) genome equivalents gave a 100% certainty of detecting an infected fetus. Higher viral loads were associated with fetuses or newborns with symptoms.

CONCLUSIONS

IgM tests and the IgG avidity determination can identify all women at risk of transmitting CMV. Furthermore, a high CMV DNA load in amniotic fluid could be an indicator of symptomatic congenital infection at a relatively early stage of pregnancy.

Prenatal diagnosis of fetal primary cytomegalovirus infection

OBJECTIVE

To determine the reliability of prenatal diagnosis for congenital cytomegalovirus in women with primary infection.

DESIGN

Retrospective analysis of case records between 1992 and 1997.

SETTING

Fetal medicine unit of a large teaching hospital.

POPULATION

Forty-two pregnant women with primary cytomegalovirus infection.

METHODS

Fetal diagnosis was made by amniocentesis for viral culture and amplification of cytomegalovirus DNA by polymerase chain reaction (n = 37), or by cordocentesis for the detection of cytomegalovirus-specific IgM antibodies (n = 13). All patients had serial ultrasonographic scans in order to detect those fetuses with abnormalities that could be associated with cytomegalovirus infection.

RESULTS

Fourteen pregnancies (33 x 3%) had evidence of vertical transmission. Nine out of 14 (64 x 3%) had positive amniotic fluid culture, while 11 (78 x 6%) had positive polymerase chain reaction results. The combination of both tests allowed antenatal diagnosis in 12 of the 14 infected fetuses (sensitivity 85 x 7%). All women who underwent cordocentesis for the detection of cytomegalovirus-specific IgM antibodies had negative results, but in two cases cytomegalovirus infection was detected by amniotic fluid studies. In five of the infected fetuses there were abnormal ultrasonographic findings. All pregnancies with evidence of vertical transmission were terminated and the remainder proceeded normally to term.

CONCLUSIONS

Our data showed that amniotic fluid studies, preferably polymerase chain reaction amplification of viral DNA, are the best diagnostic tools for the detection of vertical transmission in pregnancies with primary cytomegalovirus infection. For women with positive amniotic fluid studies who elect to continue their pregnancies, cordocentesis and serial ultrasound scans may be useful for assessment of fetal status.

Prenatal diagnosis of human cytomegalovirus by culture and polymerase chain reaction: 98 pregnancies leading to congenital infection

Human cytomegalovirus (HCMV) is the most common cause of viral intra-uterine infection. The experience with prenatal diagnosis remains limited and is based on few reports of small numbers of cases. It is thus difficult to compare the accuracy of the different tests because the groups studied were small and heterogeneous. We describe here our experience on a series of 98 pregnancies leading to HCMV congenital infection, among which 71 have been tested by amniotic fluid (AF) sampling followed by culture and/or polymerase chain reaction (PCR). Independently of the delay between AF sampling and the first HCMV IgM positive result, the mean sensitivity of both culture and PCR was around 70 per cent. The best sensitivity (95.5 per cent) was obtained after a delay > or = 6 weeks in late pregnancy (> or = 23 weeks). The present study demonstrated clearly that the delay between AF puncture and the presumed date of seroconversion is more important for sensitivity than the technique used for the diagnosis (PCR or culture). However, even in the best diagnostic conditions, negative results of HCMV culture or PCR in AF cannot formally exclude intra-uterine infection.

Ultrasound and fetal diagnosis of perinatal infection

Prenatal ultrasound can aid the clinician in evaluation of the patient with a suspected in utero TORCH infection, particularly toxoplasmosis, syphilis, and CMV. Demonstration of characteristic ultrasound findings in the high risk patient has a high predictive value for fetal infection and also may have prognostic significance. The sonologist should understand the limitations of ultrasound, discuss them with the patient, and document the discussion in the medical record. Patients should be counseled that ultrasound is not a sensitive test for fetal infection and that a normal fetal anatomy survey cannot predict a favorable outcome. In the low-risk patient, fetal infection should be considered when multiple organ system anomalies, fetal growth restriction, placental enlargement, or abnormalities of amniotic fluid volume are demonstrated.

Predictive value of maternal-IgG avidity for congenital human cytomegalovirus infection

BACKGROUND

Human cytomegalovirus (HCMV) is now the most common cause of viral intrauterine infection. Fetal damage is mostly linked to maternal primary infection. It is therefore important to differentiate primary from recurrent or persistent HCMV infection in pregnant females. For this purpose, IgM tests are not reliable enough and the measurement of the IgG avidity appears to be presently the best method.

OBJECTIVE

To evaluate the performance of the measurement of HCMV-IgG avidity by a 8 M urea denaturation assay in predicting congenital infection in the offspring.

STUDY DESIGN

Seventy-eight women were included in this study on the basis of a HCMV IgM positive or equivocal result on a first serum during pregnancy, but without a documented seroconversion history. The IgG avidity was measured and correlated with the outcome of the pregnancy.

RESULTS

In eight cases of HCMV in utero infection the maternal HCMV-IgG avidity index was below 50%. One case of HCMV in utero infection was observed despite a high avidity index during the second trimester of the pregnancy. High or intermediate HCMV-IgG avidity indexes during the first trimester of pregnancy were not associated with a congenital infection.

CONCLUSIONS

Even in the presence of an IgM positive result, an HCMV IgG avidity index above 65% on a serum obtained during the first trimester of pregnancy could reasonably be considered as a good indicator of past HCMV infection. In these conditions invasive prenatal diagnosis is not necessary.

Prenatal diagnosis of congenital cytomegalovirus infection

We report here the results of a study on the prenatal diagnosis of congenital cytomegalovirus (CMV) infection. The study was carried out by both PCR and virus isolation from amniotic fluid (AF) for 82 pregnant women at risk of transmitting CMV for the detection of (i) seroconversion to CMV immunoglobulin G (IgG) positivity during the first trimester of pregnancy, (ii) symptomatic CMV infection in the mother during the first trimester of pregnancy or intrauterine growth retardation detected by ultrasound or abnormal ultrasonographic findings suggestive of fetal infections, and (iii) seropositivity for CMV-specific IgM. For 50 women, fetal blood (FB) was also obtained and tests for antigenemia and PCR were performed. The results indicate that AF is better than FB for the prenatal diagnosis of CMV infection. PCR with AF has a sensitivity (SNS) of 100%, a specificity (SPE) of 83.3%, a positive predictive value (PPV) of 40%, and a negative predictive value (NPV) of 100%; rapid virus isolation with the same material has an SNS of 50%, an SPE of 100%, a PPV of 100%, and an NPV of 94.7%. Fewer than 10% of the women positive for IgM by enzyme immunoassay (EIA) had a congenitally infected fetus or newborn infant. When EIA IgM positivity was confirmed by Western blotting (WB) and the WB profile was considered, the percent transmission detected among women with an "at-risk" profile was higher than that observed among IgM-positive women and was the same as that among women who seroconverted during the first trimester of pregnancy (transmission rates of 29 and 25%, respectively).

Improved prenatal diagnosis of congenital human cytomegalovirus infection by a modified nested polymerase chain reaction

Two major variables may cause false-negative results in prenatal diagnosis of congenital human cytomegalovirus (HCMV) infection: sensitivity of the techniques(s) used; and time elapsed between maternal infection and antenatal testing. Previous results indicated that rapid HCMV isolation from amniotic fluid samples and viral DNA detection in amniotic fluid by nested polymerase chain reaction (nPCR) had comparable levels of sensitivity (69.2% and 76.9%, respectively). The nPCR protocol was reviewed following two additional false-negative antenatal diagnosis in a twin pregnancy during which two procedures were performed at 18 and 23 weeks of gestation, respectively. In the new assay, multiple (instead of single) and 100 (instead of 20) microliters amniotic fluid aliquots were individually amplified and tested by nPCR. By using this approach, low DNA levels (1-10 genome equivalents) were detected in 1-5/8 replicates of amniotic fluid samples taken from both twins during both procedures. In addition, viral DNA was detected in 5/6 replicates from two amniotic fluid samples still available from two previous false-negative cases. However, nPCR on multiple amniotic fluid replicates did not anticipate positive prenatal results in a retrospective case, which required two procedures for correct diagnosis and, when prospectively employed, did not avoid one additional false-negative prenatal diagnosis 8 weeks after maternal infection. Thus, delayed intrauterine transmission of the infection may be a potential cause of false-negative results. However, the combination of a very sensitive technique with appropriate timing of prenatal testing can substantially increase the reliability of prenatal diagnosis results.

Perinatal herpesvirus infections. Herpes simplex, varicella, and cytomegalovirus

The herpesvirus infections (herpes simplex, varicella, and cytomegalovirus) create many dilemmas when encountered during pregnancy. This article reviews the epidemiologic diagnosis and management of perinatal herpesvirus infections. A review of possible future trends is also included.

Recent advances in the diagnosis of cytomegalovirus infection

Herpesviruses are highly disseminated in nature, and nearly 100 Herpesviruses have been at least partially characterized. Seven Herpesviruses have been isolated so far from humans and one has recently been detected by sequence analysis. Consequently, the diagnosis of human Herpesvirus infection is based on eight different viruses. The diagnosis of a Herpesvirus infection can be achieved through the direct demonstration of the presence of the virus or its components (mainly nucleic acids and antigens) in pathological materials or indirectly through serology. In recent years much progress has been made in both directions and thanks to the detailed study of the viral genomes and their antigenic gene products and by the determination of the immune reactivity against individual antigenic polypeptides in different clinical settings. Progress in the direct detection of the viruses in pathological materials mainly regards the production of specific probes and their use with or without DNA amplification for the detection of viral genomes. Serological advances are mainly linked to the production, characterization and use of specific viral antigens by DNA recombinant procedures and by the production and use of synthetic peptides acting as good antigenic epitopes.

Treatment of murine cytomegalovirus salivary-gland infection by combined therapy with ganciclovir and thymic humoral factor gamma 2

An optimal therapeutic regimen against primary CMV salivary-gland infection has not yet been developed. We used a murine CMV (MCMV) model system to assess the ability of combined thymic humoral factor THF-gamma 2 immunotherapy and ganciclovir (GCV) antiviral chemotherapy to eliminate detectable viral DNA from salivary glands of infected animals. Mice in different experimental groups were inoculated intraperitoneally with MCMV, treated, and then sacrificed either 2 weeks or 3 months later. To amplify and detect MCMV DNA in infected salivary-gland tissue, we developed a sensitive polymerase chain reaction (PCR) using a glycoprotein B gene primer pair that amplifies a 356 bp segment. During the acute phase of the infection, the detection of high titers of infectious virus in the salivary glands correlated with a strong PCR amplification signal. Although active virions could not be recovered from untreated animals 3 months after viral inoculation, the PCR assay detected a latent MCMV genome. Treatment with either GCV alone or THF-gamma 2 alone had little or no effect on the presence of MCMV DNA. By contrast, combined treatment with THF-gamma 2 and GCV significantly reduced the amount of salivary-gland MCMV DNA to below the limit of PCR detection. The results presented here, and experimental data from previous MCMV research in our laboratories, imply that elimination of the virus from the salivary glands could be due in part to THF-gamma 2 restoration of the various MCMV-suppressed, cell mediated immune-responses. Combining THF-gamma 2 immunotherapy and GCV antiviral chemotherapy may be an important step toward an effective therapeutic regimen that has the potential to prevent the establishment of viral latency ensuing from primary MCMV salivary-gland infection.

Prenatal diagnosis of fetal cytomegalovirus infection in seropositive pregnant women

Thirty two pregnant women, immune to human cytomegalovirus (HCMV) before conception, were examined with a combination of amniocentesis, and blood sampling for fetal HCMV infection. The pregnant women had no history of recurrent infection and they all had normal ultrasonographic findings. Maternal sera and amniotic fluids were examined for anti-HCMV antibodies and viral DNA by enzyme immunoassay and polymerase chain reaction (PCR). All maternal sera were negative for viral DNA and IgM anti-HCMV antibodies. However, HCMV DNA was detected in the amniotic fluid of four pregnant women. These four cases were considered as fetal HCMV infections. Three of them were followed up after birth. The three neonates appeared clinically normal at birth, but HCMV DNA was detected in their urine specimens and in two of them in the cord blood sera. Although the neonates were asymptomatic at birth, the possibility of developing sequelae later on, cannot be excluded. The results show that HCMV recurrent maternal infection is silent and difficult to be suspected and diagnosed. They also show that fetal HCMV infection is not rare among pre-immune pregnant women.

Evaluation of virological procedures to detect fetal human cytomegalovirus infection: avidity of IgG antibodies, virus detection in amniotic fluid and maternal serum

Human cytomegalovirus (HCMV) is the most common cause of viral intrauterine infection and fetal damage largely due to maternal primary infection. Virological procedures which are able to detect HCMV fetal infection were evaluated. HCMV IgG antibodies were detected in 62.5% of the pregnant women and 1.47% had a primary infection. From March, 1992 to August, 1995, 29 seroconversions were observed, and in 64 other cases. HCMV IgM antibodies were detected in the first serological test. The mean IgG antibody avidity test (AI) was 31% for the 11 seroconversions tested and 74% in 32 cases where IgG and IgM HCMV antibodies were detected in the first serum. In the 29 HCMV seroconversions, 19 amniocentesis were carried out and 12 fetuses (41.4%) were infected in utero. In four amniotic fluids positive in culture and PCR, the fetus or newborns were infected and in one out of the two cordocentesis undertaken, hepatitis, anemia, and thrombocytopenia were noted. In four other cases, investigations seeking HCMV in amniotic fluid were negative whereas infants were infected at birth. Among the 64 cases with positive HCMV IgM and IgG antibodies detected in the first serological test, three fetuses were infected in utero, but no amniotic fluid was available in these cases. Amniotic fluids were studied in 39 cases, and HCMV detection by culture and PCR-hybridization was negative. HCMV DNA was detected in the maternal sera of five out of 21 pairs of seroconversions and in two cases on the first negative serum. The assay was also carried out on 50 of the 64 HCMV IgM positive sera. Two had detectable HCMV DNA.

Infection materno-foetale à cytomégalovirus

Congenital cytomegalovirus infection is frequent. Symptomatic disease at birth is infrequent but very severe. In most cases the infection is totally asymptomatic but neurosensorial damage can occur in 10 % to 15 % of children, hearing loss being the most frequent. Maternal or neonatal screening is the only way to recognise asymptomatic disease. Wether the screening has to be done, and if so when, will be discussed here.

Congenital cytomegalovirus infection: a long-standing problem still seeking a solution

OBJECTIVE

The purpose of this study was to review the accuracy of current tests used for the diagnosis of in utero cytomegalovirus infection and to discuss the potential value of preconceptional and postconceptional screening programs for prevention of congenital infection.

STUDY DESIGN

A computer-assisted search was performed for relevant English language publications between 1987 and 1994. We identified 119 cases of suspected intrauterine cytomegalovirus infection in which either amniotic fluid or fetal blood had been analyzed antenatally.

RESULTS

Congenital cytomegalovirus infection affects 0.5% to 2.5% of all newborns. The rate of transmission to the fetus after primary infection during pregnancy ranges from 15% to 50%. Of the fetuses infected in utero, 10% exhibit congenital cytomegalovirus syndrome. Evaluation of 119 cases of suspected infection has shown that polymerase chain reaction and cultures of amniotic fluid are the most reliable tests for prenatally determining the presence of viral particles. However, efficacy of routine antenatal screening in reducing the rate of fetal disease is limited.

CONCLUSION

It is concluded that at present the accuracy of tests used for the diagnosis of in utero cytomegalovirus infection is undetermined. Serologic screening of all pregnant women is of limited value and at present is not recommended.

Polymerase chain reaction for prenatal diagnosis of congenital human cytomegalovirus infection

The reliability of the polymerase chain reaction (PCR) for prenatal diagnosis of human cytomegalovirus (HCMV) infection was determined by retrospective testing of 35 amniotic fluids identified previously as positive or negative for HCMV by virus isolation. Amniocentesis was performed in 26 pregnant women with primary HCMV infection at 14-36 weeks gestation, 3-21 weeks after maternal infection. Blood samples were obtained from 20 fetuses for IgM determination and/or virus isolation. Amniotic fluid culture led to antenatal diagnosis of HCMV in 9 of the 13 infected fetuses (sensitivity 69.2%) with one case diagnosed at a second sampling. PCR was able to detect one additional infected fetus (10/13, sensitivity 76.9%). Nested PCR did not increase sensitivity of prenatal diagnosis. Three cases were not diagnosed by all the techniques employed. The specificity of virus isolation from and DNA detection by PCR in amniotic fluid was 100%. The negative predictive value for virus isolation from amniotic fluid was 76.5% and for DNA detection by PCR 81.2%, whereas the positive predictive value was 100% for both techniques. The results showed that neither approach can detect all cases of congenital HCMV infection prenatally, and that the time interval between maternal infection and sampling seems to be a major factor affecting the reliability of prenatal diagnosis.

Congenital cytomegalovirus infection

OBJECTIVE

Congenital cytomegalovirus is the most common viral infection affecting approximately 1% of newborns. The virus can be transmitted to the fetus during both primary and recurrent infection. Although most of the infants are asymptomatic at birth, up to 15% develop late complications. The annual cost of treating cytomegalovirus infection complications in the USA is two billion US dollars. Many issues regarding cytomegalovirus infection such as routine screening, antenatal diagnosis and vaccination during pregnancy are unsettled and disputed. The aim of this article is to review the current literature on the subject and to draw some conclusions.

DESIGN

Review of the current literature.

CONCLUSIONS

At present, it appears that there is no indication for routine prenatal screening, while other issues, such as the most accurate method for antenatal diagnosis and the indications for pregnancy termination are, as yet, unsettled.

Accuracy of amniotic fluid testing before 21 weeks' gestation in prenatal diagnosis of congenital cytomegalovirus infection

Cytomegalovirus (CMV) is the most common cause of intrauterine infection. Recent publications show amniocentesis to have an 81-100 per cent sensitivity in antenatal diagnosis after 21 weeks' gestation. Testing before 21 weeks' gestation is less well documented. We performed 36 amniocenteses between 14 and 20 weeks' gestation. The sensitivity was 45 per cent and the specificity 100 per cent. Implications and possible causes of this low sensitivity are discussed.

Prenatal diagnosis of congenital human cytomegalovirus infection

Fifteen fetuses at risk of congenital human cytomegalovirus (HCMV) infection underwent prenatal diagnosis at 16-30 weeks' gestation by a combination of amniocentesis and fetal blood sampling. HCMV was isolated from the amniotic fluid in six patients, but HCMV-specific IgM was detected in only three of them. Two of the nine neonates, who were delivered following a negative prenatal diagnosis, had congenital HCMV infection diagnosed by virus isolation in the urine. The interval from infection to prenatal testing was 3 and 4 weeks in the two false-negative cases and > or = 7 weeks in the true-positive cases. Although timely testing for HCMV infection allows the option of termination of pregnancy, it may be flawed by false-negative results.

Detection of congenital cytomegalovirus infection by using chorionic villi of the early pregnancy and polymerase chain reaction

OBJECTIVE

To detect congenital cytomegalovirus (CMV) infection of chorionic villi in early pregnancy.

METHODS

Extraction of DNA of chorionic villi and amplification of the gene of major immediate-early (MIE) antigen of CMV using a polymerase chain reaction (PCR).

RESULTS

Sixty-eight specimens of chorionic villi and 16 specimens were positive for CMV infection by PCR. The incidence of congenital CMV infection in the first trimester of pregnancy was 23.5%.

CONCLUSIONS

The risk of transmission of CMV from mother to fetus in early pregnancy is very high and potential CMV carriers may transmit CMV to their fetus in early pregnancy.

Cytomegalovirus infection in pregnancy

Cytomegalovirus (CMV) infection is of great importance to obstetrician-gynecologists because maternal infection is relatively common and can result in severe injury to the fetus. The greatest risk to the fetus occurs when the mother develops a primary CMV infection in the first trimester. Forty to 50% of infants delivered to mothers with primary CMV infections will have congenital infections. Of these neonates, 5–18% will be overtly symptomatic at birth. Approximately 30% of severely infected infants die, and 80% have severe neurologic morbidity. Eighty-five to 90% of infants will be asymptomatic, and 10–15% of these babies subsequently have sequelae such as visual and auditory defects. If the mother develops a recurrent or reactivated CMV infection during pregnancy, the risk of a severe congenital infection is very low. Perinatal infection, as opposed to congenital infection, may result from exposure to the virus during delivery or lactation and rarely leads to serious sequelae. Antimicrobial therapy and immunotherapy for CMV are, at present, unsatisfactory. Therefore, all patients, pregnant women in particular, must be educated about preventive measures.