Mother-to-infant transmission of hepatitis C virus: a prospective study

No. 96-The Reproductive Care of Women Living With Hepatitis C Infection

OBJECTIVE

hepatitis C virus (HCV) is an increasingly important public health problem worldwide. Health care workers providing care to women of childbearing age are uniquely placed in their practices to identify a significant proportion of at-risk patients and to provide appropriate screening and counselling. The primary objective of this guideline is to provide accurate, current information to those offering reproductive care to women living with HCV. This document is also intended to raise awareness of HCV in both the medical and general populations.

OPTIONS

the areas of clinical practice considered in formulating this guideline are disease prevention, targeted screening of individuals at risk of contracting HCV, management of identified patients in the context of reproductive care, and the appropriate referral of patients to those with particular expertise.

OUTCOMES

implementation of these guidelines should facilitate identification of infected individuals. It should also result in improved physical and mental well-being for patients and their families and reduction in transmission rates.

EVIDENCE

the literature between 1966 and 2000, including non- English language publications, was extensively searched utilizing Medline. A multidisciplinary group consisting of experts within the fields of obstetrics and gynaecology, infectious diseases, hepatology, and public health convened in Montreal in February 2000. The working group also included a patient and a representative from the Hepatitis C Society of Canada. The level of evidence for the recommendations has been determined using the criteria described by the Canadian Task Force on Periodic Health Examination.

BENEFITS, HARMS AND COSTS

the public health benefits of increased identification of at-risk individuals, diagnosis, treatment, implementation of risk reduction behaviours, and reduced transmission rates, both on an individual and at the community level, are significant. However, it must be remembered that the diagnosis of a chronic disease may have far reaching effects for the individual patient and her family.

RECOMMENDATIONS

VALIDATION: references were collected through Medline searches and comparison made to existing current guidelines for assessment of consistency. External reviewers expert in their field were also consulted.

Pathogenesis of hepatitis C during pregnancy and childhood

The worldwide prevalence of HCV infection is between 1% and 8% in pregnant women and between 0.05% and 5% in children. Yet the pathogenesis of hepatitis C during pregnancy and in the neonatal period remains poorly understood. Mother-to-child transmission (MTCT), a leading cause of pediatric HCV infection, takes place at a rate of <10%. Factors that increase the risk of MTCT include high maternal HCV viral load and coinfection with HIV-1 but, intriguingly, not breastfeeding and mode of delivery. Pharmacological prevention of MTCT is not possible at the present time because both pegylated interferon alfa and ribavirin are contraindicated for use in pregnancy and during the neonatal period. However, this may change with the recent introduction of direct acting antiviral agents. This review summarizes what is currently known about HCV infection during pregnancy and childhood. Particular emphasis is placed on how pregnancy-associated immune modulation may influence the progression of HCV disease and impact MTCT, and on the differential evolution of perinatally acquired HCV infection in children. Taken together, these developments provide insights into the pathogenesis of hepatitis C and may inform strategies to prevent the transmission of HCV from mother to child.

Chronic hepatitis C virus infection in children and adolescents: Epidemiology, natural history, and assessment of the safety and efficacy of combination therapy

Hepatitis C virus (HCV) is the most common cause of chronic liver disease of infectious etiology in children. Most of the children infected with HCV are asymptomatic, and only a few of them develop signs and symptoms of end-stage liver disease early in life. It is not possible to predict either in which patients HCV infection will have a bad outcome or the critical time in early adulthood when disease progression will accelerate. The experiences with therapy in children with chronic hepatitis C are based on earlier and continuing data from adult trials. The currently recommended treatment for chronic HCV infection in adults is the combination of peginterferon-á and ribavirin. The choice of this regimen is based on the results of randomized clinical trials that demonstrated the superiority of this combination treatment over standard interferon-á and ribavirin. Recently, results of pivotal, multicenter, interventional open-label studies on combined treatment with peginterferon-á and ribavirin in children have been published, and the US Food and Drug Administration and the European Medicines Agency have approved the combination therapy in those older than 3 years. The aim of this review is to evaluate critically the available data regarding the safety and efficacy of combination treatment with peginterferon-á and ribavirin in children.

Perinatal transmission of hepatitis C virus infection

In industrialized countries, hepatitis C virus (HCV) is the most common cause of chronic liver disease in children. Perinatal transmission is the leading cause of infection. Perinatal transmission is confined almost always to women with detectable HCV ribonucleic acid (RNA) in the peripheral blood by the polymerase chain reaction but all children born to women with anti-HCV antibodies should be tested for HCV. Some but not all studies found that a high concentration of serum HCV RNA is associated with a higher risk of transmission. Maternal peripheral blood mononuclear cell infection by HCV, membrane rupture of longer than 6 hr before delivery, and procedures exposing the infant to maternal blood infected with HCV during vaginal delivery are associated with an increased risk of transmission. Maternal coinfection with HCV and human immunodeficiency virus, maternal history of intravenous drug use and of HCV infection of the sexual partner of the mother predict the risk of perinatal transmission and are dependent on the peripheral blood mononuclear cell infection by HCV. Delivery by Cesarean section is not recommended in pregnant women infected with HCV. Infected mothers can breast feed safely their infants if the nipples are not damaged. A previous delivery of a child infected perinatally with HCV does not increase the risk of transmission in subsequent pregnancies. Immunogenetic factors and HCV genotypes are not related to HCV perinatal transmission. Despite an increased understanding of the risk factors involved in perinatal transmission of HCV, to date little is known about the transmission mechanisms and timing.

Transmission of hepatitis C virus infection from asymptomatic mother to child in southern India

BACKGROUND

Little information is available on the mother-to-child transmission of hepatitis C virus (HCV) in India, and no interventions to decrease transmission rates have been identified. Hence, we performed a long-term prospective study in infants born to HCV-positive mothers, with the aim of evaluating vertical transmission of HCV and correlated risks factors.

METHODS

Three thousand one hundred and fifteen healthy asymptomatic pregnant women were included in the study. We used third-generation (Murex anti-HCV) ELISA and HCV RNA reverse transcription PCR (RT-PCR) for screening, and the commercial line probe assay (Inno-LiPA) and direct sequencing HCV genotyping assays were performed to confirm the transmitted HCV genotypes.

RESULTS

Of the total 3115 healthy asymptomatic pregnant women, 18 (0.6%) were positive for anti-HCV. Of the 18 anti-HCV-positive women, eight (44.4%) were positive for HCV RNA RT-PCR. HCV transmission was observed in two of the eight babies born to eight HCV RNA-positive mothers who were followed up for 12 months. HCV genotyping of the mother/child pairs revealed the persistent presence of mixed genotypes 1a and 4 throughout the follow-up period. None of the non-viremic (HCV RNA-negative) mothers transmitted HCV infection to their baby. In our study approximately 25% of vertical/perinatal transmission of HCV was observed among HCV RNA-positive antenatal women.

CONCLUSIONS

This study is of importance as it is the first report from India of a successful attempt to analyze the rate of vertical/perinatal transmission of HCV from infected mothers to their children by a prospective longitudinal follow-up study, and to characterize the pattern of genotype(s) of HCV present in the infected mother/baby pairs, so as to confirm the source of HCV acquired by the newborn babies.

Hepatitis C and pregnancy

Hepatitis C is the most common chronic bloodborne infection in the United States. The diagnosis of vertical transmission is reliably established by a positive serum hepatitis C virus (HCV) RNA on 2 occasions 3 to 4 months apart after the infant is at least 2 months old and/or by the detection of anti-HCV antibodies after the infant is 18 months old. Vertical transmission in HCV RNA-negative pregnant women is approximately 1% to 3% versus approximately 4% to 6% in HCV RNA-positive women. From the standpoint of vertical transmission, no critical HCV RNA titer has been established. Coinfection with HIV has been shown to increase the risk of vertical transmission of HCV, but highly active antiretroviral therapy may decrease the risk significantly. In HIV-negative women, route of delivery does not influence vertical transmission. In HCV/HIV-coinfected women, decisions regarding mode of delivery should be based on HIV status. There is no association between vertical transmission of HCV and gestational age at delivery or the presence of chorioamnionitis. The use of a scalp electrode has been associated with vertical transmission and this practice is discouraged. Data are conflicting regarding duration of ruptured membranes and the risk of vertical transmission of hepatitis C. When the duration of membrane rupture exceeds 6 hours, the risk may be increased. There is no evidence demonstrating an increased risk of HCV transmission in HIV-negative women who breast feed. In HCV/HIV-coinfected women, breast feeding is discouraged in women who have consistent access to safe infant formula.

TARGET AUDIENCE

Obstetricians & Gynecologists, Family Physicians.

LEARNING OBJECTIVES

After completion of this article, the reader should be able to recall that vertical transmission of hepatitis C (HCV) does occur, state that coinfection with HIV increases the transmission rate, and summarize that there is no association between gestational age or presence of chorioamnionitis and no evidence that a cesarean delivery prevents transmission.

Discordant outcome of perinatal transmission of hepatitis C in twin pregnancies

BACKGROUND

Mother to infant transmission of hepatitis C virus (HCV) is dependent on significant HCV viraemia being present in the mother. As yet there are no appropriate interventions to prevent perinatal transmission. The investigation of twin pregnancies where only one twin is infected may reveal further information relating to transmission and specific risks. Evaluation of these risks could affect decisions about the management of the deliveries of these mothers while more appropriate interventions are evaluated.

STUDY DESIGN

The laboratory database was searched for all twins referred for testing at the Children's Hospital Liver Unit. The mothers and health care providers were contacted to gain more information about the pregnancies and deliveries of all of the twins.

RESULTS

Four sets of twins had been investigated for HCV. In all cases only one twin had been infected. In three out of four cases the second twin had become infected. All of the twins were girls and the larger twin in each pair became infected. Premature rupture of membranes was associated with transmission in the only case in which the first-born became infected. There was no invasive foetal monitoring or episiotomy in any of the deliveries

SUMMARY AND CONCLUSIONS

Transmission of HCV is more likely to affect the second twin, perhaps because placental separation during the delivery of the second twin exposes the infant to infection. Until effective interventions such as vaccination of newborns or antiviral treatment of mothers are evaluated, elective caesarean section could be recommended for HCV twin pregnancies in order to avoid premature membrane rupture and infection of the second twin.

Drug abuse, innate immunity and hepatitis C virus

Since its discovery in 1989, hepatitis C virus (HCV) has become a major public health problem. HCV chronically infects an estimated 170 million people worldwide. The seroprevalence of anti-HCV antibody in the United States has been estimated at 1.8%, which corresponds to approximately 4 million people. HCV is the most common chronic blood borne infection in the United States, and the leading cause of liver transplantation in developed countries. Injection drug use is the dominant mode of HCV transmission and accounts for up to 90% of current infections. Opiates and other drug abuse, such as alcohol, have been implicated as cofactors in the pathogenesis of HCV disease. Injection drug use has been the most common risk factor identified in alcoholics with HCV infection. Both opiates and alcohol contribute significantly to morbidity and mortality from HCV disease. These drugs most likely act synergistically to promote the development and progression of HCV disease. However, there is limited information available concerning the interaction of the drug abuse with the host cell innate immunity against HCV infection, which is a major barrier to fundamental understanding of the immunopathogenesis of HCV disease. Therefore, defining the role of the drug abuse in the development of chronic HCV infection is of crucial importance and should provide practical guidance toward the reduction of risk factors that interfere with therapeutic approaches for HCV infection and disease. This review paper focuses on the interplay between drug abuse (opiates and alcohol), innate immunity and HCV in the context of the development of HCV disease.

Evolution in the hypervariable region of the hepatitis C virus in two infants infected by mother-to-infant transmission

BACKGROUND

There is little data on the evolution of hepatitis C virus (HCV) quasispecies in infants infected by mother-to-infant transmission during long-term follow up. The hypervariable region 1 (HVR1) of the HCV genome was investigated in two mother-infant pairs from birth to 7.6 and 10.2 years, respectively.

METHODS

Ten cDNA clones of HVR1 generated from HCV-RNA and extracted from serum samples of both pairs were analyzed. The sequences were compared with regard to variability, identity, and hydrophobia profile, and analyzed by phylogenetic studies.

RESULTS

The alanine aminotransferase (ALT) level was high with fluctuation in infant A and almost within the normal range in infant B. Sequence diversity was higher in infant A at 7.6 years than in infant B at 9.3 years (sequence identity with the mothers'; 69.3-70.7% vs 85.3-90.7% for nucleotides, and 48% vs 68-72% for amino acids, respectively). Compared to the first samples, amino acid changes greatly increased in infant A (35.2% at 4.9 years and 52% at 7.6 years), but not in infant B (4% at 5.6 years and 27.5% at 9.3 years). Phylogenetic studies revealed that quasispecies in infant A evolved to a greater extent than that in infant B. Hydrophobia profile analyses revealed that dynamic shifts between hydrophilia and hydrophobia occurred in both infants.

CONCLUSIONS

As in adults, the evolution of HVR1 and variability of quasispecies increased in infants infected through mother-to-infant transmission for 10 years after birth. A large episode of ALT elevation suggested the emergence of escape mutants and the evolution of new quasispecies.

Vertical transmission of hepatitis C virus in a hospital in southern Brazil

BACKGROUND: There still are controversies concerning the vertical transmission of hepatitis C virus. AIM: To evaluate the prevalence of antibodies against hepatitis C virus in pregnant women, as well as the rate of vertical transmission of this virus. PATIENTS AND METHODS: Between August 1998 and November 1999, 1,090 consecutive pregnant women were screened for anti-hepatitis C virus; positive results were confirmed by the polymerase chain reaction assay. Patient's viral load was evaluated by the branched deoxyribonucleic acid assay. Hepatitis C virus genotype was identified by direct sequencing of the polymerase chain reaction amplification products. The same tests were performed in the children born from infected mothers at the 1st and 6th month of life. RESULTS: Of the 1,090 mothers surveyed, 29 were positive for anti-hepatitis C virus (prevalence of 2.66%). Twenty-five patients presented with hepatitis C virus RNA, with a median hepatitis C virus viral load of 3.132 ± 5.891 MEq/mL. Twenty-two patients (six human immunodeficiency virus-coinfected) were followed and gave birth to 23 children; 18 of them had blood samples tested at the 1st month of life, and 22, at the 6th month. Vertical transmission rate was 5.56%; it affected a girl who had hepatitis C virus RNA detectable only in the 1st month sample (41.570 MEq/mL). The mother who transmitted hepatitis C virus was coinfected with human immunodeficiency virus and presented with an hepatitis C virus viral load of 3.765 MEq/mL, with 100% homology with her daughter's hepatitis C virus genotype. CONCLUSION: These results suggest that the prevalence of hepatitis C virus infection in pregnant women should not be neglected, and early diagnosis of vertical transmission and the follow up of infected children should be emphasized.

Hepatitis C Infection: A Clinical Review

Nearly three million persons in the United States are viremic with hepatitis C (HCV). Despite a decreasing incidence of HCV in this country, the prevalence of HCV-related chronic liver disease is increasing. Most infections in the United States are acquired by intravenous drug use. The chronicity rate of HCV is high, reaching 85% in some populations, and the risk of progression to advanced liver disease is as high as 20% within twenty years of infection. Host factors like alcohol use accelerate the rate of progression. The enzyme immunoassay is the preferred initial test for diagnosis; the third generation assay has greater than a 99% specificity in immunocompetent patients. Barring contraindications, the standard of care for treatment of chronic HCV has become pegylated interferon and ribavirin. With this therapy, the cure rate for treatment-naïve patients is about 55%, but rates are higher in certain groups. Common side effects of therapy include neuropsychiatric symptoms, influenza-like symptoms and hematological abnormalities.

Maternal-infant transmission of hepatitis C virus infection

Mother-to-infant transmission of hepatitis C virus (HCV) is comparatively uncommon. The prevalence of antibody to HCV (anti-HCV) in pregnant women is 0.1% to 2.4%, although in some endemic areas it is much higher. The proportion of women with anti-HCV who have active infection with viremia is 60% to 70%. Transmission of HCV occurs only when serum HCV RNA is detectable and may be related to higher levels (above 10(6) copies per mL). The rate of mother-to-infant transmission is 4% to 7% per pregnancy in women with HCV viremia. Co-infection with human immunodeficiency virus (HIV) increases the rate of transmission 4 to 5 fold. The actual time and mode of transmission are not known. Elective Cesarean section is not recommended for women with chronic HCV infection alone. The role of treatment to prevent transmission is limited by the fetal toxicity of currently available medications for hepatitis C. Breast feeding poses no important risk of HCV transmission if nipples are not traumatized and maternal hepatitis C is quiescent. Pregnant women at high risk for HCV infection should be screened for anti-HCV, and HCV RNA testing should be performed if anti-HCV is positive. Infants of women with hepatitis C should be tested for HCV RNA on two occasions, between the ages of 2 and 6 months and again at 18 to 24 months, along with serum anti-HCV. The natural history of mother-to-infant hepatitis C remains uncertain, especially the course in the first year of life when some infants appear to have spontaneous resolution.

Maternal-infant transmission of hepatitis C virus infection

Mother-to-infant transmission of hepatitis C virus (HCV) is comparatively uncommon. The prevalence of antibody to HCV (anti-HCV) in pregnant women is 0.1% to 2.4%, although in some endemic areas it is much higher. The proportion of women with anti-HCV who have active infection with viremia is 60% to 70%. Transmission of HCV occurs only when serum HCV RNA is detectable and may be related to higher levels (above 10(6) copies per mL). The rate of mother-to-infant transmission is 4% to 7% per pregnancy in women with HCV viremia. Co-infection with human immunodeficiency virus (HIV) increases the rate of transmission 4 to 5 fold. The actual time and mode of transmission are not known. Elective Cesarean section is not recommended for women with chronic HCV infection alone. The role of treatment to prevent transmission is limited by the fetal toxicity of currently available medications for hepatitis C. Breast feeding poses no important risk of HCV transmission if nipples are not traumatized and maternal hepatitis C is quiescent. Pregnant women at high risk for HCV infection should be screened for anti-HCV, and HCV RNA testing should be performed if anti-HCV is positive. Infants of women with hepatitis C should be tested for HCV RNA on two occasions, between the ages of 2 and 6 months and again at 18 to 24 months, along with serum anti-HCV. The natural history of mother-to-infant hepatitis C remains uncertain, especially the course in the first year of life when some infants appear to have spontaneous resolution.

Intra-hepatic cholestasis of pregnancy in hepatitis C virus infection

BACKGROUND

Aims of this study were to investigate whether hepatitis C virus infection influences the incidence and natural history of intrahepatic cholestasis of pregnancy (ICP) and whether ICP has different characteristics in hepatitis C virus (HCV) positive women from ICP in HCV negative women.

METHODS

A prospective study for the prevalence of the HCV infection and for the incidence of ICP was carried out in the 5840 patients admitted to the Prenatal Department of Padua University, Italy, between January 1996 and January 1999. Testing was done for HCV by the enzyme linked immunosorbent assay (ELISA 3), recombinant immuno blot assay (RIBA 3) and polymerase chain reaction (PCR). The diagnosis of ICP was made on clinical grounds based on the occurence of pruritus with onset during pregnancy, persisting up to the time of delivery and disappearing after delivery, supported by demonstrating an elevation of both serum ALT and total serum bile acids. The Student's t-test, one way anova and chi-square tests were used for statistical analysis.

RESULTS

During the study period, 56 of 5840 patients developed ICP (0.96%). Of these, 12 were also HCV-RNA positive. The rate of ICP was observed more commonly in HCV-RNA positive women than in HCV-RNA negative women (20.33% or 12/59 versus 0.78% or 44/5767, P = 0.001

CONCLUSIONS

Occurrence of ICP during the third trimester should be an indication to investigate the HCV status of the patient. Although the diagnosis of ICP is not confirmed by specific tests, we confirmed a higher risk of HCV infection in this condition. Therefore, occurence of ICP during the third trimester should be an indication to investigate the HCV status of the patient. Broader studies are necessary to assess the impact of infection on the perinatal outcome of ICP.

Hepatitis C: an epidemiological review

The aim of the study was to analyse the current literature regarding the mode of transmission of HCV and its global prevalence in different groups of people. A systematic review of the literature on the epidemiology of hepatitis C from 1991 to 2000 using computerized bibliographic databases which include Medline, Current Content and Embase. The prevalence of hepatitis C virus (HCV) varies tremendously in different parts of the world, with the highest incidence in the Eastern parts of the globe compared with the Western parts. Furthermore, certain groups of individuals such as intravenous drug users are at increased risk of acquiring this disease irrespective of the geographical location. Although the main route of transmission is via contaminated blood, curiously enough in up to 50% of the cases no recognizable transmission factor/route could be identified. Therefore, a number of other routes of transmission such as sexual or household exposure to infected contacts have been investigated with conflicting results. Hepatitis C infection is an important public health issue globally. Better understanding of routes of transmission will help to combat the spread of disease. In order to prevent a world wide epidemic of this disease, urgent measures are required to (i) develop a strategy to inform and educate the public regarding this disease and (ii) expedite the efforts to develop a vaccine.

Hepatitis C. Epidemiologic quandaries

Although many aspects of the transmission of HCV have been clarified, some important issues remain controversial, and the conventional wisdom may be based more on opinion than data (Table 2). HCV is transmitted by percutaneous exposure to contaminated blood, uncommonly from a mother to her infant and between sexual partners, and rarely during the provision of medical care in developed nations. Improved behavioral research instruments are needed to further the understanding of the practices that actually transmit infection. In addition, large, prospective studies are necessary to characterize the frequency [table: see text] of transmission between sexual partners and the potential role of cesarian section in reducing HCV transmission to infants.

Evolution of the E2 region of hepatitis C virus in an infant infected by mother-to-infant transmission

To demonstrate vertical transmission of hepatitis C virus from an HCV infected woman and to assess the evolution of HCV quasispecies in the infant, the variable E2 region was analyzed in one mother-infant pair at birth and in serial samples from the infected baby. Sequence analysis of the E2 region obtained by means of direct sequencing of PCR products of mother-infant pair at birth, showed that the sequence of the dominant strain in the infant was related closely but not identical to that of her mother. The HCV population in mother-infant pair at birth and in serial samples of the infant was analyzed by polymerase-chain reaction-mediated Single Strand Conformational Polymorphism analysis (SSCP), which can distinguish DNA fragments of the same size as different electrophoretic migration of single stranded DNA. Single Strand Polymorphism analysis revealed that the infant was infected with two mutant genomes whereas the mother had a unique variant. The prevalent strain detected in the baby was not dominant in the mother at delivery and the pattern of quasispecies in the infant at birth was not the same as her mother, suggesting that the infant acquired the infection in utero. Changes in the dominant strain and evolution of the pattern of quasispecies in the infant from the 10th month of age were possibly due to the immune selection of escape mutants.

Clinical course of pregnant women with chronic hepatitis C virus infection and risk of mother-to-child hepatitis C virus transmission

As far as concerns chronic hepatitis C virus infection in pregnant women, different points remain to be elucidated, such as the clinical course, the rate of mother-to-child hepatitis C virus transmission and, in particular, its route and the possible risk factors. This review aimed to analyse current data on the prevalence of chronic hepatitis C virus infection in pregnant women and its relationship with risk factors, the rate of mother-to-child hepatitis C virus transmission and the factors possibly involved, particularly the maternal hepatitis C virus viral load and the human immunodeficiency virus coinfection, and the type of delivery and feeding. Finally, the appropriate timing for HCV-RNA testing in newborns has been reviewed.

[Breastfeeding and hepatitis C virus (HCV): the need for a careful appraisal]

We review the available data on the possible role of breast-feeding in hepatitis C virus (HCV) transmission to infants of HCV-RNA-positive mothers. Current knowledge about HCV excretion through breast milk, HCV infection of breast-fed infants by mothers contaminated after delivery, and vertical transmission risk to infants breast-fed by chronic HCV viremic mothers are presented. Vertical transmission risk by breast-feeding HCV-RNA-positive mothers is unclear: no study has been performed with the aim and the required methodology to evaluate HCV transmission risk related to breast-feeding duration. Recommendations to HCV-RNA-positive mothers who wish to breast-feed their infant are discussed in light of present knowledge about HCV secretion in breast milk, mother-to-infant HCV transmission, and historical records on vertical transmission of other viruses to infants breast-fed by their viremic mothers.

Prospective study of mother-to-infant transmission of hepatitis C virus

BACKGROUND

Mother-to-infant transmission of hepatitis C virus (HCV) could become the main route of HCV infection in the future because there are no methods available to prevent vertical infection. The aim of this study was to determine the incidence of mother-to-infant transmission in infants born to mothers who tested positive for anti-HCV antibodies and to elucidate associated risk factors for transmission.

METHODS

Screening was conducted for 16,800 pregnant women with an anti-HCV antibodies test, and 154 mothers were positive. From the positive group 141 mothers were enrolled in the study and their 147 infants were followed from birth for serum alanine aminotransferase activity, anti-HCV antibodies and HCV RNA. HIV infection was tested in 73 of 141 mothers, all of whom were negative.

RESULTS

Thirty-three infants were dropped from the study because they were followed for <6 months or were not tested adequately. Of the 114 infants finally evaluated 9 (7.8%) had detectable HCV RNA. The transmission rate was not influenced by the mode of delivery [vaginal delivery, 8 of 90 vs. cesarean section, 1 of 24 (P = 0.396)] or by the type of feeding [9 of 98 for breast-fed infants vs. 0 of 16 for formula-fed infants (P = 0.243)]. All infected infants were born to mothers who had HCV viremia at the delivery (P = 0.040) and to those with a high viral load (P = 0.019).

CONCLUSIONS

Our prospective study showed that the transmission rate of mother-to-infant HCV infection was 7.8% in anti-HCV antibody-positive mothers. Risk was related to the presence of maternal HCV viremia at delivery and a high viral load in the mothers.

Mother-to-infant transmission of hepatitis C virus

The rate of mother-to-infant transmission of hepatitis C virus (HCV) is approximately 5%, but is higher when the mother is co-infected with HIV Vertical transmission is restricted to infants whose mothers are viraemic. The risk of transmission increases with increasing maternal viral load but a specific cut-off value predicting infection cannot be defined. There is no specific HCV genotype which is preferentially transmitted. The mode of delivery (caesarean versus vaginal) does not appear to influence the rate of transmission, but firm evidence is lacking. There is no evidence to suggest an increased risk of HCV transmission through breast feeding. Pregnancy is not contra-indicated in HCV-infected women. Without drugs to treat established infections in mothers and infants and interventions to prevent vertical transmission, routine HCV screening is not recommended in pregnant women.

Hepatitis C epidemiology

Hepatitis C virus infection occurs in all parts of the world. Infection is generally due to percutaneous exposures, though sexual and perinatal transmission may occur. While further study is needed to elucidate the biology of HCV transmission and develop vaccines for prevention, new HCV infections can be reduced by economic development and education regarding blood-borne infections.

Detection of hepatitis C virus RNA (HCV RNA) in amniotic fluid: a prospective study

BACKGROUND/AIMS

Mother-to-infant transmission of hepatitis C virus (HCV) has been reported, but the transmission route is unknown. The aim of our study was to detect HCV RNA in amniotic fluid of pregnant women seropositive for HCV.

METHODS

Twenty-two HCV seropositive women were included in the study (median age: 39 years). An amniocentesis was performed in all patients during the 4th month of pregnancy. Sixteen women also tested positive for HCV RNA in serum. The range of HCV RNA titers was 0.3 to 15.1x10(6) Eq/ml (Quantiplex HCV RNA 2.0 Assay, Chiron Diagnostics). Of these 16 viremic patients, four had an anterior placenta, ten had a posterior placenta and the position of the placenta was not determined in two cases. PCR (Amplicor HCV, Roche Diagnostics) was used to detect HCV RNA in the amniotic fluid. We also studied 11 HCV seronegative women as a control group.

RESULTS

In the viremic group (n = 16), HCV RNA was detected once in amniotic fluid. The positive specimen was collected from a patient with an HCV RNA serum value equal to 1.1x10(6) Eq/ml. The placenta was in an anterior position. A PCR inhibitor was detected in one case. No HCV RNA was detected in the amniotic fluid of six seropositive non-viremic patients, nor in the control group. Serum HCV RNA was negative in the ten children tested. The woman whose amniotic fluid contained HCV RNA was the mother of one of them.

CONCLUSIONS

HCV RNA detection in amniotic fluid is rarely positive. The anterior position of the placenta in the only positive detection cannot rule out contamination of the amniotic fluid during the transplacental amniocentesis.

Hepatitis C--role of perinatal transmission

To evaluate the role of perinatal transmission in the spread of hepatitis C virus (HCV), we screened a cohort of pregnant intravenous drug using (IVDU) women for HCV antibody detection; where seropositive HCV RNA detection by polymerase chain reaction (PCR) was found we followed the infants longitudinally for HCV antibody and HCV RNA. Serum prevalence for HCV for this population was 80% with HCV RNA detected in 50%. Recruitment and follow-up over a 3-year period of a cohort of 83 seropositive women, their 91 newborns and 16 siblings of newborns, showed that there had been a 3% perinatal transmission rate with 1 sibling also infected. These positive cases were defined as transient in 1 case (HCV RNA positive by PCR at 1 month, but seronegative and HCV RNA negative at 10 months of age), 2 unevaluable (HCV RNA positive at 2 months of age, but patients lost to follow-up), and 1 chronic infection in a child at 34 months (positive HCV RNA and seropositive 34-month sibling). Maternal HCV RNA levels for those with infected infants was a mean 40-fold greater than those whose babies were uninfected, although this did not reach statistical significance. Of the remaining infants, the majority (93%) had lost passively acquired maternal antibodies by 9 months of age and all by 12 months. Of 18 women who were HCV seropositive and breast feeding (66% of whom were HCV RNA positive in their sera), none had detectable HCV RNA in breast milk. Hence we conclude that transmission of HCV from mother to infant appears to be of low frequency and positivity appears to correlate with maternal circulating viral load.

Hepatitis C virus infection in the mothers and infants cohort study

OBJECTIVES

To estimate the hepatitis C virus (HCV) vertical transmission rate, the effect of potential risk factors, and the pattern of HCV antibody response and viremia in HCV-infected infants.

STUDY DESIGN

The Mothers and Infants Cohort Study enrolled both human immunodeficiency virus (HIV)-seropositive and HIV-seronegative pregnant women at five obstetric clinics in New York City in a prospective cohort study between January 1986 and January 1991. HCV-infected mothers and their 122 offspring were followed-up for a minimum of 12 months for evidence of HCV infection as determined by persistent HCV antibodies or detection of HCV RNA by reverse transcription polymerase chain reaction. Comparisons among groups for categorical variables were performed using the Fisher's exact test.

RESULTS

Seven (6%; 95% confidence interval, 2%-11%) of the 122 infants were HCV-infected. There was a tendency for increased risk of transmission with maternal viral and obstetrical factors, such as coinfection with HIV (7% vs 4%), high HIV viral load (13% vs 6%), HCV viremia (8% vs 3%), vaginal delivery (6% vs 0%), and female gender of offspring (8% vs 3%), although none of the associations reached statistical significance. After loss of maternal antibody, HCV antibody seroconversion occurred at a mean age of 26 months in 3 HIV-coinfected infants compared with 7 months of age in 4 HCV-infected HIV-uninfected infants. Serial samples showed that HCV RNA persisted in 6 infants for at least 18 to 54 months.

CONCLUSIONS

Our study is in accordance with other studies that have shown low overall HCV vertical transmission risk and a trend toward higher risk with maternal risk factors such as HIV-coinfection or HCV viremia. A delay in infant HCV antibody response may be associated with HIV coinfection although larger studies are needed to confirm these findings.

Hepatitis in pregnancy

The study of viral hepatitis was expanded over the past decade with the emergence of new viruses, therapies, and vaccination guidelines as well as new data on the risks of perinatal transmission. There are now at least six hepatitis viruses. Hepatitis A and E are causes of epidemic, enteric infection and do not carry a significant risk of chronic infection. Hepatitis B, C, D, and G are hematogenously spread and are significant causes of chronic hepatitis, hepatocellular carcinoma, and cirrhosis. The following report reviews the types of hepatitis as well as the consequences of infection to the mother and fetus.

Seroprevalence and mother-to-infant transmission of hepatitis C in asymptomatic Egyptian women

OBJECTIVES

In this study, we sought to determine (1) the prevalence of hepatitis C virus (HCV) RNA, or its antibodies, in a healthy parturient Egyptian population and (2) the risk of mother-to-infant transmission in this population.

METHOD

The serum of 499 pregnant Egyptian women was tested for anti-HCV with ELISA-3 and for HCV RNA by polymerase chain reaction (PCR). Neonatal cord blood and infant blood were similarly tested for anti-HCV and HCV RNA.

RESULTS

Recombinant immunoblot assay (RIBA) detected anti-HCV in 65/499 (13%) women; of these, 20/65 (31%) were PCR-positive. The total number of babies born was 499. Of the original group, 97 mothers and infants (HCV-negative) were lost to follow up and were excluded. Sixty-five anti-HCV-positive infants were born vaginally to the 65 anti-HCV-positive mothers, of which twenty (31%) corresponding mothers and babies were also positive for HCV RNA. Of these twenty babies, three died of hepatocellular disease by six months of age; sixteen developed chronic liver disease; the remaining nine remained asymptomatic but were serologically and PCR-positive. The mother-to-infant transmission rate was significantly increased (5%; P < 0.0001). Of the seropositive children, 45/65 (69%; P < 0.0001) seroreverted by eighteen months of age.

CONCLUSION

There is a high prevalence of anti-HCV in healthy pregnant Egyptian women and vertical transmission is a major risk for chronic HCV carriers.

Hepatitis C virus infection in pediatric patients

In contrast to our understanding of hepatitis C virus infection in adults, relatively little is known about the evolution and treatment of HCV infection in pediatric patients. Children at risk for HCV infection include recipients of multiple blood-product transfusions, organ transplantation and infants born to HCV-infected mothers. A proportion of HCV-infected pediatric patients do not have an identifiable risk factor. HCV infection is commonly detected in children previously presumed to have non-A, non-B hepatitis and cryptogenic liver disease. HCV infection usually leads to mild chronic liver disease in children but is also associated with chronic active hepatitis and cirrhosis. Interferon therapy is effective in a proportion of patients with chronic hepatitis C.

Use of polymerase chain reaction and antibody tests in the diagnosis of vertically transmitted hepatitis C virus infection

Data on patterns of polymerase chain reaction (PCR) and antibody test results in infants born to hepatitis C virus (HCV)-infected mothers were systematically reviewed to aid development of optimum testing schedules and diagnostic criteria for vertically exposed infants and to facilitate early identification of infected infants. Survival and cross-sectional analyses were used to estimate the timing of initial PCR positivity and subsequent PCR negativity in infected infants, and maternal antibody loss in uninfected infants was estimated as a weighted average of individual study findings. Of 74 eligible infants with strong evidence of HCV infection, an estimated 89% (90% confidence interval, 80-95%) were first PCR positive by 3 months of age, and less than 10% had subsequent PCR negativity attributable to intermittent viraemia or resolved infection in the first 18 months of life. The negative predictive value of PCR at 3 months of age was greater than 98% at an assumed rate of 5% vertical transmission, but as low as 88% at 25% transmission. The inclusion of 22 infants, each with a single PCR-positive result, increased the estimated frequency of resolved infections but made little difference to other estimates. A minority of PCR-positive infants had periods of antibody negativity by second- or third-generation assays, and among 297 uninfected infants, maternal antibody was not detected beyond 18 months. Thus, the majority of infected infants may be persistently PCR positive from 3 months of age, and the negative predictive value of PCR at 3 months is generally high. However, poor repeatability of PCR, inadequate infant follow-up, and inclusion of postnatally infected infants limits interpretation of the pooled data. Further studies using standardised PCR methodologies are needed.

Hepatitis C virus infection in pregnancy and the risk of mother-to-child transmission

The risk of vertical transmission of the hepatitis C virus (HCV) from infected mothers to their children during pregnancy and delivery was determined in 120 children born to HCV-positive mothers. Methods included enzyme immunoassay and immunoblot for detection of HCV antibodies and reverse transcription polymerase chain reaction (RT-PCR) for detection of viral RNA. Six (5%) children were perinatally infected with HCV as shown by RT-PCR. None of the infected children had clinical signs of hepatitis. None of the pregnancies was complicated by abortion, stillbirth, premature birth, or malformation of the child. Special concern was given to the possibility of HCV transmission via breast milk. In no breast milk sample obtained from 34 HCV-infected mothers was HCV RNA detected. These observations indicate that HCV infection is not necessarily a contraindication for breast-feeding.

Rapidly progressive hepatitis C in a patient with common variable immunodeficiency

A 15-year-old girl with common variable immunodeficiency contracted hepatitis C, which progressed to liver cirrhosis and finally to hepatic failure 5 years later. Since she was agammaglobulinaemic, hepatitis C virus (HCV) infection was diagnosed on the basis of HCV-RNA detection. Quantification of her sera showed high levels of HCV-RNA (more than 10(7) copies of RNA/mL), which implied active viral replication. There were no other hepatotoxic factors except HCV infection. The initial liver biopsy at 16 years of age and the autopsy confirmed a rapid progression in liver histopathological change over 4 years.

CONCLUSION

Contrary to the widely held view of a benign short-term prognosis in paediatric hepatitis C, progressive fatal liver disease can develop in some patients with HCV infection. Such a rapid progression of liver injury provides the rationale for antiviral therapy in at least certain high risk groups of these children. Hepatitis C may progress rapidly in an immune deficiency condition.