Am J Perinatol 2013; 30(02): 149-160
DOI: 10.1055/s-0033-1334459
Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

Hepatitis C Virus in Pregnancy

Mona R. Prasad
1   Division of Maternal Fetal Medicine, Department of Obstetrics and Gynecology, Wexner Medical Center, The Ohio State University College of Medicine, Columbus, Ohio
,
Jonathan R. Honegger
2   Department of Pediatrics, The Ohio State University College of Medicine, Columbus, Ohio
3   Center for Vaccine and Immunity, The Research Institute, Nationwide Children's Hospital, Columbus, Ohio
› Author Affiliations
Further Information

Publication History

05 January 2013

16 January 2013

Publication Date:
06 February 2013 (online)

Abstract

Despite recent advances in the pathogenesis, treatment, and public health response to hepatitis C virus (HCV), HCV as it specifically relates to pregnancy has been a neglected condition. HCV-monoinfected pregnant women have a 2-8% risk of viral transmission to their infant, but the mechanism and timing of mother to child transmission (MTCT) are not fully understood, nor is the natural history of the illness in pregnant women and their offspring. Recognition of HCV-infected pregnant women is relevant because of the long-term health implications for the mother, potential adverse effects of infection on pregnancy outcomes, and the possibility of transmission to their infants. Certain risk factors for MTCT of HCV appear similar to those for human immunodeficiency virus (HIV); however, unlike HIV, effective methods for prevention of HCV vertical transmission have not been developed. It is possible that a better understanding of HCV MTCT and pathogenesis in pregnancy will guide development of useful prevention strategies, particularly as we enter an era where interferon-free drug cocktails may emerge as viable treatment options for HCV.

 
  • References

  • 1 Shepard CW, Finelli L, Alter MJ. Global epidemiology of hepatitis C virus infection. Lancet Infect Dis 2005; 5: 558-567
  • 2 Armstrong GL, Wasley A, Simard EP, McQuillan GM, Kuhnert WL, Alter MJ. The prevalence of hepatitis C virus infection in the United States, 1999 through 2002. Ann Intern Med 2006; 144: 705-714
  • 3 Lauer GM, Walker BD. Hepatitis C virus infection. N Engl J Med 2001; 345: 41-52
  • 4 Davis GL, Alter MJ, El-Serag H, Poynard T, Jennings LW. Aging of hepatitis C virus (HCV)-infected persons in the United States: a multiple cohort model of HCV prevalence and disease progression. Gastroenterology 2010; 138: 513-521 , e1–e6
  • 5 Arshad M, El-Kamary SS, Jhaveri R. Hepatitis C virus infection during pregnancy and the newborn period—are they opportunities for treatment?. J Viral Hepat 2011; 18: 229-236
  • 6 Mitchell AE, Colvin HM, Palmer Beasley R. Institute of Medicine recommendations for the prevention and control of hepatitis B and C. Hepatology 2010; 51: 729-733
  • 7 Poordad F, Dieterich D. Treating hepatitis C: current standard of care and emerging direct-acting antiviral agents. J Viral Hepat 2012; 19: 449-464
  • 8 Ge D, Fellay J, Thompson AJ , et al. Genetic variation in IL28B predicts hepatitis C treatment-induced viral clearance. Nature 2009; 461: 399-401
  • 9 Smith BD, Morgan RL, Beckett GA , et al; Centers for Disease Control and Prevention. Recommendations for the identification of chronic hepatitis C virus infection among persons born during 1945–1965. MMWR Recomm Rep 2012; 61: 1-32
  • 10 Cottrell EB, Chou R, Wasson N, Rahman B, Guise JM. Reducing risk for mother-to-infant transmission of hepatitis C virus: a systemic review for the U.S. Preventative Services Task Force. Ann Int Med 2013; 158: 109-113
  • 11 Practice Bulletin No ACOG. American College of Obstetricians and Gynecologists. 86: Viral hepatitis in pregnancy. Obstet Gynecol 2007; 110: 941-956
  • 12 Alter MJ, Margolis HS, Bell BP , et al; Centers for Disease Control and Prevention. Recommendations for prevention and control of hepatitis C virus (HCV) infection and HCV-related chronic disease. MMWR Recomm Rep 1998; 47: 1-39
  • 13 Giles M, Hellard M, Sasadeusz J. Hepatitis C and pregnancy: an update. Aust N Z J Obstet Gynaecol 2003; 43: 290-293
  • 14 Blasig A, Wagner EC, Pi D , et al; BC HCV Vertical Transmission Study Group. Hepatitis C infection among pregnant women in British Columbia: reported prevalence and critical appraisal of current prenatal screening methods. Can J Public Health 2011; 102: 98-102
  • 15 Pinto CS, Martins RM, Andrade SM, Stief AC, Oliveira RD, Castro AR. Hepatitis C virus infection among pregnant women in Central-Western Brazil, 2005–2007. Rev Saude Publica 2011; 45: 974-976
  • 16 Conte D, Fraquelli M, Prati D, Colucci A, Minola E. Prevalence and clinical course of chronic hepatitis C virus (HCV) infection and rate of HCV vertical transmission in a cohort of 15,250 pregnant women. Hepatology 2000; 31: 751-755
  • 17 Ward C, Tudor-Williams G, Cotzias T, Hargreaves S, Regan L, Foster GR. Prevalence of hepatitis C among pregnant women attending an inner London obstetric department: uptake and acceptability of named antenatal testing. Gut 2000; 47: 277-280
  • 18 Delgado-Borrego A, Smith L, Jonas MM , et al. Expected and actual case ascertainment and treatment rates for children infected with hepatitis C in Florida and the United States: epidemiologic evidence from statewide and nationwide surveys. J Pediatr 2012; 161: 915-921
  • 19 Plunkett BA, Grobman WA. Routine hepatitis C virus screening in pregnancy: a cost-effectiveness analysis. Am J Obstet Gynecol 2005; 192: 1153-1161
  • 20 Wilson JM, Jungner YG. Principles and practices of screening for disease. Bol Oficina Sanit Panam 1968; 65: 281-393
  • 21 Nyamathi AM, Dixon EL, Robbins W , et al. Risk factors for hepatitis C virus infection among homeless adults. J Gen Intern Med 2002; 17: 134-143
  • 22 Fox RK, Currie SL, Evans J , et al. Hepatitis C virus infection among prisoners in the California state correctional system. Clin Infect Dis 2005; 41: 177-186
  • 23 Macalino GE, Dhawan D, Rich JD. A missed opportunity: hepatitis C screening of prisoners. Am J Public Health 2005; 95: 1739-1740
  • 24 Bohman VR, Stettler RW, Little BB, Wendel GD, Sutor LJ, Cunningham FG. Seroprevalence and risk factors for hepatitis C virus antibody in pregnant women. Obstet Gynecol 1992; 80: 609-613
  • 25 Silverman NS, Jenkin BK, Wu C, McGillen P, Knee G. Hepatitis C virus in pregnancy: seroprevalence and risk factors for infection. Am J Obstet Gynecol 1993; 169: 583-587
  • 26 Mast EE, Hwang LY, Seto DS , et al. Risk factors for perinatal transmission of hepatitis C virus (HCV) and the natural history of HCV infection acquired in infancy. J Infect Dis 2005; 192: 1880-1889
  • 27 Bradley JS, Graham S, Picchio GR, Vugia DJ, Kharrazi M. Prevalence of hepatitis C virus antibody in newborn infants in southern California in 2003. Pediatr Infect Dis J 2011; 30: 618-620
  • 28 Centers for Disease Control and Prevention (CDC). Notes from the field: risk factors for hepatitis C virus infections among young adults—Massachusetts, 2010. MMWR Morb Mortal Wkly Rep 2011; 60: 1457-1458
  • 29 Centers for Disease Control and Prevention (CDC). Notes from the field: hepatitis C virus infections among young adults—rural Wisconsin, 2010. MMWR Morb Mortal Wkly Rep 2012; 61: 358
  • 30 Salihu HM, Connell L, Salemi JL, August EM, Weldeselasse HE, Alio AP. Prevalence and temporal trends of hepatitis B, hepatitis C, and HIV/AIDS co-infection during pregnancy across the decade, 1998–2007. J Womens Health (Larchmt) 2012; 21: 66-72
  • 31 Alter MJ, Margolis HS, Krawczynski K , et al. The natural history of community-acquired hepatitis C in the United States. The Sentinel Counties Chronic non-A, non-B Hepatitis Study Team. N Engl J Med 1992; 327: 1899-1905
  • 32 Hoofnagle JH. Course and outcome of hepatitis C. Hepatology 2002; 36 (5) (Suppl. 01) S21-S29
  • 33 Rehermann B. Hepatitis C virus versus innate and adaptive immune responses: a tale of coevolution and coexistence. J Clin Invest 2009; 119: 1745-1754
  • 34 Thomas DL, Thio CL, Martin MP , et al. Genetic variation in IL28B and spontaneous clearance of hepatitis C virus. Nature 2009; 461: 798-801
  • 35 Khakoo SI, Thio CL, Martin MP , et al. HLA and NK cell inhibitory receptor genes in resolving hepatitis C virus infection. Science 2004; 305: 872-874
  • 36 Kogure T, Ueno Y, Kanno N , et al. Sustained viral response of a case of acute hepatitis C virus infection via needle-stick injury. World J Gastroenterol 2006; 12: 4757-4760
  • 37 Gonzalez F, Medam-Djomo MA, Lucidarme D , et al. Acute hepatitis C during the third trimester of pregnancy. Gastroenterol Clin Biol 2006; 30: 786-789
  • 38 Wejstål R, Widell A, Norkrans G. HCV-RNA levels increase during pregnancy in women with chronic hepatitis C. Scand J Infect Dis 1998; 30: 111-113
  • 39 Gervais A, Bacq Y, Bernuau J , et al. Decrease in serum ALT and increase in serum HCV RNA during pregnancy in women with chronic hepatitis C. J Hepatol 2000; 32: 293-299
  • 40 Paternoster DM, Santarossa C, Grella P , et al. Viral load in HCV RNA-positive pregnant women. Am J Gastroenterol 2001; 96: 2751-2754
  • 41 Lin HH, Kao JH. Hepatitis C virus load during pregnancy and puerperium. BJOG 2000; 107: 1503-1506
  • 42 Hattori Y, Orito E, Ohno T , et al. Loss of hepatitis C virus RNA after parturition in female patients with chronic HCV infection. J Med Virol 2003; 71: 205-211
  • 43 Watanabe H, Saito T, Shinzawa H , et al. Spontaneous elimination of serum hepatitis C virus (HCV) RNA in chronic HCV carriers: a population-based cohort study. J Med Virol 2003; 71: 56-61
  • 44 Honegger J, Prasad M, Walker C. Broadened virus-specific T-cell responses are associated with postpartum declines in hepatitis C viremia, Abstract 1225. In: Infectious Diseases Society of America Annual Meeting. San Diego, CA: 2012
  • 45 Le Campion A, Larouche A, Fauteux-Daniel S, Soudeyns H. Pathogenesis of hepatitis C during pregnancy and childhood. Viruses 2012; 4: 3531-3550
  • 46 Connell LE, Salihu HM, Salemi JL, August EM, Weldeselasse H, Mbah AK. Maternal hepatitis B and hepatitis C carrier status and perinatal outcomes. Liver Int 2011; 31: 1163-1170
  • 47 Floreani A, Paternoster D, Zappala F , et al. Hepatitis C virus infection in pregnancy. Br J Obstet Gynaecol 1996; 103: 325-329
  • 48 Hillemanns P, Dannecker C, Kimmig R, Hasbargen U. Obstetric risks and vertical transmission of hepatitis C virus infection in pregnancy. Acta Obstet Gynecol Scand 2000; 79: 543-547
  • 49 Pergam SA, Wang CC, Gardella CM, Sandison TG, Phipps WT, Hawes SE. Pregnancy complications associated with hepatitis C: data from a 2003–2005 Washington state birth cohort. Am J Obstet Gynecol 2008; 199: e1-e9
  • 50 Reddick KL, Jhaveri R, Gandhi M, James AH, Swamy GK. Pregnancy outcomes associated with viral hepatitis. J Viral Hepat 2011; 18: e394-e398
  • 51 Berkley EM, Leslie KK, Arora S, Qualls C, Dunkelberg JC. Chronic hepatitis C in pregnancy. Obstet Gynecol 2008; 112 (2 Pt 1) 304-310
  • 52 Locatelli A, Roncaglia N, Arreghini A, Bellini P, Vergani P, Ghidini A. Hepatitis C virus infection is associated with a higher incidence of cholestasis of pregnancy. Br J Obstet Gynaecol 1999; 106: 498-500
  • 53 Paternoster DM, Fabris F, Palù G , et al. Intra-hepatic cholestasis of pregnancy in hepatitis C virus infection. Acta Obstet Gynecol Scand 2002; 81: 99-103
  • 54 White DL, Ratziu V, El-Serag HB. Hepatitis C infection and risk of diabetes: a systematic review and meta-analysis. J Hepatol 2008; 49: 831-844
  • 55 Hurtado CW, Golden-Mason L, Brocato M, Krull M, Narkewicz MR, Rosen HR. Innate immune function in placenta and cord blood of hepatitis C—seropositive mother-infant dyads. PLoS ONE 2010; 5: e12232
  • 56 Mok J, Pembrey L, Tovo PA, Newell ML. European Paediatric Hepatitis C Virus Network. When does mother to child transmission of hepatitis C virus occur?. Arch Dis Child Fetal Neonatal Ed 2005; 90: F156-F160
  • 57 Gibb DM, Goodall RL, Dunn DT , et al. Mother-to-child transmission of hepatitis C virus: evidence for preventable peripartum transmission. Lancet 2000; 356: 904-907
  • 58 Steininger C, Kundi M, Jatzko G, Kiss H, Lischka A, Holzmann H. Increased risk of mother-to-infant transmission of hepatitis C virus by intrapartum infantile exposure to maternal blood. J Infect Dis 2003; 187: 345-351
  • 59 Azzari C, Moriondo M, Indolfi G , et al. Higher risk of hepatitis C virus perinatal transmission from drug user mothers is mediated by peripheral blood mononuclear cell infection. J Med Virol 2008; 80: 65-71
  • 60 Azzari C, Resti M, Moriondo M, Ferrari R, Lionetti P, Vierucci A. Vertical transmission of HCV is related to maternal peripheral blood mononuclear cell infection. Blood 2000; 96: 2045-2048
  • 61 Nie QH, Gao LH, Cheng YQ , et al. Hepatitis C virus infection of human cytotrophoblasts cultured in vitro. J Med Virol 2012; 84: 1586-1592
  • 62 Mostafavi A, Arshad M, Qiang G, Bradrick S, Jhaveri R. Examining cells of trophoblastic origin for permissiveness for hepatitis C virus replication. Abstract 1338. In: Infectious Diseases Society of America Annual Meeting. San Diego, CA: 2012
  • 63 Babik JM, Cohan D, Monto A, Hartigan-O'Connor DJ, McCune JM. The human fetal immune response to hepatitis C virus exposure in utero. J Infect Dis 2011; 203: 196-206
  • 64 El-Kamary SS, Hashem M, Saleh DA , et al. Hepatitis C virus-specific cell-mediated immune responses in children born to mothers infected with hepatitis C virus. J Pediatr 2013; 162: 148-154
  • 65 Della Bella S, Riva A, Tanzi E , et al. Hepatitis C virus-specific reactivity of CD4 + -lymphocytes in children born from HCV-infected women. J Hepatol 2005; 43: 394-402
  • 66 Hashem M, El-Karaksy H, Shata MT , et al. Strong hepatitis C virus (HCV)-specific cell-mediated immune responses in the absence of viremia or antibodies among uninfected siblings of HCV chronically infected children. J Infect Dis 2011; 203: 854-861
  • 67 Bevilacqua E, Fabris A, Floreano P , et al; EPHN collaborators. Genetic factors in mother-to-child transmission of HCV infection. Virology 2009; 390: 64-70
  • 68 Bosi I, Ancora G, Mantovani W , et al. HLA DR13 and HCV vertical infection. Pediatr Res 2002; 51: 746-749
  • 69 Martinetti M, Pacati I, Cuccia M , et al. Hierarchy of baby-linked immunogenetic risk factors in the vertical transmission of hepatitis C virus. Int J Immunopathol Pharmacol 2006; 19: 369-378
  • 70 Indolfi G, Resti M. Perinatal transmission of hepatitis C virus infection. J Med Virol 2009; 81: 836-843
  • 71 Azzari C, Indolfi G, Betti L , et al. Vertical hepatitis C virus transmission is not related to mother-child class-1 HLA concordance. Int J Immunopathol Pharmacol 2007; 20: 827-831
  • 72 Ruiz-Extremera A, Muñoz-Gámez JA, Salmerón-Ruiz MA , et al. Genetic variation in interleukin 28B with respect to vertical transmission of hepatitis C virus and spontaneous clearance in HCV-infected children. Hepatology 2011; 53: 1830-1838
  • 73 European Paediatric Hepatitis C Virus Network. A significant sex—but not elective cesarean section—effect on mother-to-child transmission of hepatitis C virus infection. J Infect Dis 2005; 192: 1872-1879
  • 74 Giacchino R, Tasso L, Timitilli A , et al. Vertical transmission of hepatitis C virus infection: usefulness of viremia detection in HIV-seronegative hepatitis C virus-seropositive mothers. J Pediatr 1998; 132: 167-169
  • 75 Dal Molin G, D'Agaro P, Ansaldi F , et al. Mother-to-infant transmission of hepatitis C virus: rate of infection and assessment of viral load and IgM anti-HCV as risk factors. J Med Virol 2002; 67: 137-142
  • 76 Granovsky MO, Minkoff HL, Tess BH , et al. Hepatitis C virus infection in the mothers and infants cohort study. Pediatrics 1998; 102 (2 Pt 1) 355-359
  • 77 Resti M, Azzari C, Galli L , et al; Italian Study Group on Mother-to-Infant Hepatitis C Virus Transmission. Maternal drug use is a preeminent risk factor for mother-to-child hepatitis C virus transmission: results from a multicenter study of 1372 mother-infant pairs. J Infect Dis 2002; 185: 567-572
  • 78 Dore GJ, Kaldor JM, McCaughan GW. Systematic review of role of polymerase chain reaction in defining infectiousness among people infected with hepatitis C virus. BMJ 1997; 315: 333-337
  • 79 Boxall E, Baumann K, Price N, Sira J, Brown M, Kelly D. Discordant outcome of perinatal transmission of hepatitis C in twin pregnancies. J Clin Virol 2007; 38: 91-95
  • 80 Spencer JD, Latt N, Beeby PJ , et al. Transmission of hepatitis C virus to infants of human immunodeficiency virus-negative intravenous drug-using mothers: rate of infection and assessment of risk factors for transmission. J Viral Hepat 1997; 4: 395-409
  • 81 Thomas SL, Newell ML, Peckham CS, Ades AE, Hall AJ. A review of hepatitis C virus (HCV) vertical transmission: risks of transmission to infants born to mothers with and without HCV viraemia or human immunodeficiency virus infection. Int J Epidemiol 1998; 27: 108-117
  • 82 Minola E, Maccabruni A, Pacati I, Martinetti M. Amniocentesis as a possible risk factor for mother-to-infant transmission of hepatitis C virus. Hepatology 2001; 33: 1341-1342
  • 83 Delamare C, Carbonne B, Heim N , et al. Detection of hepatitis C virus RNA (HCV RNA) in amniotic fluid: a prospective study. J Hepatol 1999; 31: 416-420
  • 84 Indolfi G, Azzari C, Moriondo M, Lippi F, de Martino M, Resti M. Alanine transaminase levels in the year before pregnancy predict the risk of hepatitis C virus vertical transmission. J Med Virol 2006; 78: 911-914
  • 85 Polis CB, Shah SN, Johnson KE, Gupta A. Impact of maternal HIV coinfection on the vertical transmission of hepatitis C virus: a meta-analysis. Clin Infect Dis 2007; 44: 1123-1131
  • 86 Zanetti AR, Tanzi E, Paccagnini S , et al; Lombardy Study Group on Vertical HCV Transmission. Mother-to-infant transmission of hepatitis C virus. Lancet 1995; 345: 289-291
  • 87 Blackard JT, Smeaton L, Hiasa Y , et al. Detection of hepatitis C virus (HCV) in serum and peripheral-blood mononuclear cells from HCV-monoinfected and HIV/HCV-coinfected persons. J Infect Dis 2005; 192: 258-265
  • 88 Paccagnini S, Principi N, Massironi E , et al. Perinatal transmission and manifestation of hepatitis C virus infection in a high risk population. Pediatr Infect Dis J 1995; 14: 195-199
  • 89 Airoldi J, Berghella V. Hepatitis C and pregnancy. Obstet Gynecol Surv 2006; 61: 666-672
  • 90 Roberts EA, Yeung L. Maternal-infant transmission of hepatitis C virus infection. Hepatology 2002; 36 (5) (Suppl. 01) S106-S113
  • 91 Plunkett BA, Grobman WA. Elective cesarean delivery to prevent perinatal transmission of hepatitis C virus: a cost-effectiveness analysis. Am J Obstet Gynecol 2004; 191: 998-1003
  • 92 McIntyre PG, Tosh K, McGuire W. Caesarean section versus vaginal delivery for preventing mother to infant hepatitis C virus transmission. Cochrane Database Syst Rev 2006; (4) CD005546
  • 93 Kumar RM, Shahul S. Role of breast-feeding in transmission of hepatitis C virus to infants of HCV-infected mothers. J Hepatol 1998; 29: 191-197
  • 94 Lin HH, Kao JH, Hsu HY , et al. Absence of infection in breast-fed infants born to hepatitis C virus-infected mothers. J Pediatr 1995; 126: 589-591
  • 95 Yeung LT, King SM, Roberts EA. Mother-to-infant transmission of hepatitis C virus. Hepatology 2001; 34: 223-229
  • 96 European Paediatric Hepatitis C Virus Network. Effects of mode of delivery and infant feeding on the risk of mother-to-child transmission of hepatitis C virus. BJOG 2001; 108: 371-377
  • 97 American College of Obstetricians and Gynecologists. ACOG Practice Bulletin No. 86: Viral hepatitis in pregnancy. Obstet Gynecol 2007; 110: 941-956
  • 98 Ghany MG, Strader DB, Thomas DL, Seeff LB. American Association for the Study of Liver Diseases . Diagnosis, management, and treatment of hepatitis C: an update. Hepatology 2009; 49: 1335-1374
  • 99 Roberts SS, Miller RK, Jones JK , et al. The Ribavirin Pregnancy Registry: Findings after 5 years of enrollment, 2003–2009. Birth Defects Res A Clin Mol Teratol 2010; 88: 551-559
  • 100 Yazdani Brojeni P, Matok I, Garcia Bournissen F, Koren G. A systematic review of the fetal safety of interferon alpha. Reprod Toxicol 2012; 33: 265-268
  • 101 Ghany MG, Nelson DR, Strader DB, Thomas DL, Seeff LB. American Association for Study of Liver Diseases. An update on treatment of genotype 1 chronic hepatitis C virus infection: 2011 practice guideline by the American Association for the Study of Liver Diseases. Hepatology 2011; 54: 1433-1444
  • 102 Io M. Hepatitis and liver cancer: a national strategy for prevention and control of hepatitis B and C. In: Colvin HM, Mitchell AE, , eds. Committee on the Prevention and Control of Viral Hepatitis Infections; Institute of Medicine. Washington, DC: The National Academic Press; 2010
  • 103 La Torre A, Biadaioli R, Capobianco T , et al. Vertical transmission of HCV. Acta Obstet Gynecol Scand 1998; 77: 889-892
  • 104 Resti M, Azzari C, Mannelli F , et al; Tuscany Study Group on Hepatitis C Virus Infection. Mother to child transmission of hepatitis C virus: prospective study of risk factors and timing of infection in children born to women seronegative for HIV-1. BMJ 1998; 317: 437-441
  • 105 Ohto H, Terazawa S, Sasaki N , et al; The Vertical Transmission of Hepatitis C Virus Collaborative Study Group. Transmission of hepatitis C virus from mothers to infants. N Engl J Med 1994; 330: 744-750
  • 106 Tovo PA, Palomba E, Ferraris G , et al; Italian Study Group for HCV Infection in Children. Increased risk of maternal-infant hepatitis C virus transmission for women coinfected with human immunodeficiency virus type 1. Clin Infect Dis 1997; 25: 1121-1124
  • 107 Ferrero S, Lungaro P, Bruzzone BM, Gotta C, Bentivoglio G, Ragni N. Prospective study of mother-to-infant transmission of hepatitis C virus: a 10-year survey (1990–2000). Acta Obstet Gynecol Scand 2003; 82: 229-234
  • 108 Fischler B, Lindh G, Lindgren S , et al. Vertical transmission of hepatitis C virus infection. Scand J Infect Dis 1996; 28: 353-356