The presence of hepatitis B surface antigen and deoxyribonucleic acid in amniotic fluid and cord blood

The presence of hepatitis B surface antigen and deoxyribonucleic acid in amniotic fluid and cord blood Craig V. Towers, MD, Tamerou Asrat, MD, and Pamela Rumney, RNC Long Beach, California OBJECTIVE: It is uncertain whether neonatal infection with hepatitis B, despite treatment after delivery with immunoglobulin and vaccine, is the result of prior in utero transmission of the virus or treatment failure. Furthermore, the potential risk of hepatitis B transmission from the mother to the fetus at the time a genetic amniocentesis is performed is also a concern. In an attempt to better elucidate these controversies, amniotic fluid and cord blood specimens obtained from pregnant women positive for hepatitis B surface antigen were analyzed for the presence of hepatitis B surface antigen and hepatitis B deoxyribonucleic acid. STUDY DESIGN: This study was a prospective longitudinal analysis that identified hepatitis B surface antigen–positive patients who presented for amniocentesis. Cord blood was obtained from these patients at the time of delivery. Cord blood was also obtained from a group of hepatitis B surface antigen–positive patients for whom no amniocentesis was performed. All samples were analyzed for the presence of hepatitis B surface antigen and hepatitis B deoxyribonucleic acid. RESULTS: A total of 121 hepatitis B surface antigen–positive pregnant women were identified. In the 72 pregnancies in which amniocentesis was not performed, 18% of the cord blood samples were positive for hepatitis B surface antigen and 4% were positive for hepatitis B deoxyribonucleic acid. Of 47 amniocentesis fluid samples, 32% were positive for hepatitis B surface antigen but all were negative for hepatitis B virus deoxyribonucleic acid. Of 30 cord blood samples from patients who underwent an amniocentesis, 27% were positive for hepatitis B surface antigen, but all were negative for hepatitis B virus deoxyribonucleic acid. CONCLUSIONS: This study found that hepatitis B viral deoxyribonucleic acid is rarely present in cord blood and was not identified in amniotic fluid obtained by amniocentesis. This finding suggests that in utero transmission of the virus is rare prior to the onset of labor. These data further confirm the reports in the current literature that the risk of hepatitis B transmission to the fetus during amniocentesis is low. Because hepatitis B surface antigen can exist as an isolated entity devoid of nuclear material, in some cases this protein may be able to traverse the placental and amniotic membrane barrier in a manner similar to other proteins, such as α-fetoprotein. Recommendations for genetic amniocentesis in women positive for hepatitis B surface antigen are discussed. (Am J Obstet Gynecol 2001;184:1514-20.)

Key words: Amniocentesis, hepatitis B in pregnancy

Neonates of women positive for hepatitis B surface antigen (HBsAg) are at risk of becoming chronically infected, which can lead to significant future health disorders such as hepatocellular carcinoma.1 This risk is greatest for newborns of carrier mothers who are also positive for hepatitis e antigen (HBeAg). Without treatment, 65% to 90% of these newborns will become chronic carriers.2-5 However, vertical transmission can occur with pregnant women who are negative for HBeAg From the Long Beach Memorial Women’s Hospital. Funded through the Memorial Medical Center Foundation, Long Beach, California. Presented at the Sixty-seventh Annual Meeting of the Pacific Coast Obstetrical and Gynecological Society, Kamuela, Hawaii, November 14-19, 2000. Reprint requests: Craig V. Towers, MD, PO Box 8400, Huntington Beach, CA 92615-8400. Copyright © 2001 by Mosby, Inc. 0002-9378/2001 $35.00 + 0 6/6/114866 doi:10.1067/mob.2001.114866

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and even in women who have antibody to the e antigen.6 Therefore all HBsAg-positive pregnant women are at risk for transmitting the virus to their newborns. If these carrier women are appropriately identified before delivery and their newborns receive active-passive immunization with hepatitis B immunoglobulin and vaccine, the neonatal carrier rate can usually be dropped to less than 10%.2-5 Many researchers have argued that the infections that occur despite treatment are the result of in utero infection. However, treatment failure is still a possibility, especially if the newborn receives a high inoculum of virus that exceeds the capacity of the hepatitis B immunoglobulin administered. This controversy has not been fully examined. With the development of successful treatment protocols for pregnant women who are carriers of HBsAg, concern over management of hepatitis B in pregnancy has decreased.7 However, does a genetic amniocentesis performed 20 to 24 weeks prior to delivery risk transmission

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of the virus to the neonate before treatment can be administered? Every genetic amniocentesis theoretically inoculates the intrauterine cavity with maternal blood because the needle traverses the abdominal and uterine wall. In fact, visible intrauterine bleeding can be seen in up to 38% of genetic amniocentesis procedures that do not involve the placenta.8 The purpose of this study was to further analyze the issue of whether in utero transmission of hepatitis B occurs prior to the onset of labor and also to examine the controversial practice of performing a genetic amniocentesis on HBsAg-positive women. Amniotic fluid and cord blood specimens of HBsAg-positive pregnant women were analyzed for the presence of HBsAg and hepatitis B deoxyribonucleic acid (DNA). The cord blood results of patients who did and did not undergo genetic amniocentesis were compared. It is important to note that HBsAG is a protein that encapsulates the viral DNA, but this protein also can be found in the peripheral blood lacking viral DNA. Indeed, it was this HBsAg protein devoid of DNA that was purified to create the original hepatitis B vaccine.3

tained from HBsAg-positive pregnant women who did not have an amniocentesis during the pregnancy. To avoid maternal blood contamination during the collection process, the outside surface of the umbilical cord was thoroughly rinsed with normal saline solution and the cord blood was collected by direct needle puncture. Hepatitis B surface antigen testing was performed by enzyme immunoassay (Abbott Laboratories, Abbott Park, Ill). Hepatitis B DNA testing was performed by dot-blot hybridization and by polymerase chain reaction. The dotblot hybridization procedure was performed at The Liver Center, Huntington Memorial Hospital, Pasadena, Calif, as previously described.9 Study samples were run against known positive and negative controls. This procedure was capable of detecting 1 pg of hepatitis B DNA. The DNA testing by polymerase chain reaction was performed at Specialty Laboratories, Inc, in Santa Monica, Calif, which tested the amplified product on microtiter plates (Immunlon II). Minimums of 8 negative controls were run per lot. This technique is capable of detecting as few as 10 viral DNA particles per milliliter of fluid. Statistical analysis involved χ2 and Fisher exact testing, and P < .05 was considered significant.

Material and methods A prospective longitudinal study was developed at Long Beach Memorial Women’s Hospital and approved by the institutional review board. HBsAg-positive pregnant women who presented for genetic testing were identified. A full discussion of the unknown risks related to genetic amniocentesis done in patients who are positive for HBsAg was performed in conjunction with informed consent for the procedure. For women who chose to have the amniocentesis, a small sample of amniotic fluid was collected for the study. A 20- or 22-gauge needle was used, and the number of attempts, fluid color, and a transplacental procedure were recorded. The genetic amniocentesis practice at Long Beach Memorial Women’s Hospital used continuous ultrasound guidance with the collection of 20 to 30 mL of fluid (7 to 10 mL in 2 to 3 syringes) after the initial 2 to 4 mL of fluid is discarded. HBsAg and hepatitis B DNA testing was performed on a small amount of fluid from the final syringe. Patients who presented at term (>37 weeks’ gestation) to the perinatal group for the purpose of fetal lung maturity testing by amniocentesis were also evaluated for HBsAg carrier status. If the procedure was performed in a patient who was positive for HBsAG, a small amount of fluid was again analyzed for the presence of HBsAg and hepatitis B DNA. The only difference in these procedures was that a single tube of 7 to 10 mL of fluid was collected after the initial 2 to 4 mL was discarded instead of 2 to 3 tubes. At the time of delivery, an attempt was made to collect cord blood samples from the women who underwent amniocentesis. In addition, cord blood samples were also ob-

Results Fifty-eight pregnant women were identified as positive for HBsAg at the time of presentation for possible genetic testing. A total of 39 women elected to have the procedure performed. Five women declined because of the potential hepatitis risk, and 14 others declined for reasons other than hepatitis. The amniotic fluid of 37 of these 39 patients was analyzed. An additional 10 amniotic fluid samples were collected from term patients who underwent amniocentesis for fetal lung maturity testing. All 47 amniotic fluid samples were obtained on the first needle stick and were clear in color, and none were transplacental procedures. Umbilical cord blood samples were collected from all 10 of the term patients who had undergone amniocentesis, and delivery occurred within 1 to 8 days of the procedure in every case. Umbilical cord blood samples were obtained at delivery for 20 of the 39 women who underwent a genetic amniocentesis. Umbilical cord blood samples were obtained at delivery for an additional 72 pregnant women who were positive for HBsAg but who did not have an amniocentesis during the pregnancy. Thus the study population that underwent fluid analysis comprised a total of 121 HBsAg-positive pregnant women. The results of the fluid analysis are shown in Table I. Hepatitis B DNA was not detected in any of the 47 amniotic fluid samples tested. This finding suggests that in utero transmission of the intact virion is rare prior to the onset of labor (95% confidence interval, 0% to 7%). Hepatitis B DNA was not found in any of the 30 umbilical cord blood samples in patients who had undergone

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June 2001 Am J Obstet Gynecol

Table I. The presence of HBsAg and hepatitis B DNA in fluid samples tested Fluid sample tested

No. of cases

HBsAg detected (%)

Genetic amniocentesis fluid Term amniocentesis fluid Umbilical cord blood—No amniocentesis Umbilical cord blood genetic amniocentesis Umbilical cord blood term amniocentesis

37 10 72 20 10

9 (24) 6 (60) 13 (18) 6 (30) 2 (20)

Hepatitis B DNA detected (%) 0 0 3 (%) 0 0

Table II. Studies that analyzed the detection of hepatitis B DNA in the umbilical cord blood of neonates of HBsAg/HBeAg-positive pregnant women Study

No. of cases tested

No. of samples positive for hepatitis B DNA (%)

Shen et al,12 1987 Lin et al,11 1987 Lee et al,13 1988 Mitsuda et al,14 1989 Poovorawan et al,15 1997 TOTAL

16 32 97 10 19 174

0 (0) 3 (9) 13 (13) 1 (10) 0 (0) 17 (10)

amniocentesis. This finding is especially important for the 20 women who had the procedure 4 to 5 months prior to delivery. Hepatitis B DNA was detected in 3 (4%) of the 72 umbilical cord blood samples from women who did not have an amniocentesis. Two of these women were also positive for HBeAg. The e antigen status in the third woman was not determined. With regard to the surface antigen, 15 (32%) of the 47 amniotic fluid samples were positive for HBsAg (24% in the genetic amniotic fluid and 60% in the term amniotic fluid). Because these samples were all DNA negative, this finding suggests that the surface antigen protein can cross the placental/membrane barrier but not the intact virion. The presence of HBsAg in umbilical cord blood ranged from 18% in the group that did not have amniocentesis to 30% in the group that had genetic amniocentesis. This difference was not statistically significant (P = .4), although the small numbers in this comparison could result in a β error. However, it is important to note that no hepatitis B DNA was found in the cord blood of the women who underwent a genetic amniocentesis. Comment This study did not detect hepatitis B viral DNA in the amniotic fluid of 47 women who underwent sterile amniocentesis. This finding would be one indication that in utero transmission of the hepatitis B virus prior to labor is uncommon. In a Medline search of articles published in English from 1980 through March 2000, we were unable to find any other studies that have analyzed amniotic fluid for the presence of hepatitis B DNA obtained at the time of genetic amniocentesis. The fact that the surface antigen protein was detected in some of the amniotic fluid samples is consistent with a prior study that found HBsAg in 16 (26%) of 61 fluid

samples obtained by amniocentesis just prior to delivery.10 This rate is similar to the 32% rate seen in our study. Because no viral DNA was found in any of our amniotic fluid samples, this finding would suggest that in some women, the surface antigen protein devoid of DNA may be able to traverse the placental and amniotic membrane barrier, in a manner similar to that of other proteins such as fetal α-fetoprotein. Because the presence of HBsAg was higher in the term amniotic fluid versus the genetic amniotic fluid, the passage of this protein may increase as the pregnancy progresses. HBsAg was detected in 21 (21%) of 102 umbilical cord blood samples from our study. Unfortunately, the HBeAg carrier status was not analyzed in all patients. However, our surface antigen detection rate in umbilical cord blood was similar to 2 other studies that obtained samples in a similar meticulous fashion from HBeAg-positive pregnant women.10, 11 From these 2 studies, 37 (29%) of 129 umbilical cord blood samples from this high-risk population were positive for HBsAg at delivery. In our study, only 3 (3%) of 102 umbilical cord blood samples were positive for the presence of hepatitis B DNA at the time of delivery, and all 3 were in pregnancies in which an amniocentesis was not performed. Two of these women were positive for HBeAg, and the e antigen status was unknown in the third case. This detection rate is similar to that found in other studies that analyzed umbilical cord blood from HBsAg/HBeAg-positive pregnant women at the time of delivery. From 5 studies,11-15 hepatitis B DNA was detected in 17 (10%) of 174 umbilical cord blood samples from e antigen–positive pregnant women, with a range of 0% to 13% (Table II). In a study by Lee et al,13 no hepatitis B DNA was found in the umbilical cord blood from patients who had a cesarean delivery compared with 13 of 67 vaginal deliveries. This re-

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Table III. Studies that have analyzed the hepatitis B neonatal carrier status despite active-passive immunization in HBsAg-positive pregnant women for whom a genetic amniocentesis was performed (stratified by HBeAg status) Study Grosheide et al, 199417 Ko et al, 199418 Alexander et al, 199919 Total

No. of mothers eAg negative No. of neonatal HBV carriers No. of mothers eAg positive No. of neonatal HBV carriers 13 22 18 53

0 0 0 0 (0%)

2 10 1 13

0 3 0 3 (23%)

eAg, Hepatitis B e antigen; HBV, hepatitis B virus.

sult was significantly different (P = .02) and suggests that the primary route of transplacental viral transmission occurs at the time of labor, possibly related to frequent repetitive uterine contractions. Because no viral DNA was found in 30 patients who had a cesarean delivery, transplacental passage of viral DNA remote from delivery seems uncommon. With regard to the safety of genetic amniocentesis, one study found 8 failures (1%) despite passive-active immunization in 705 newborns born to HBsAg-positive women.16 Although some women underwent amniocentesis in their population, none of the 8 chronically infected newborns were born of women who had an amniocentesis. We identified 3 additional studies that analyzed the hepatitis B carrier status of infants of HBsAg-positive pregnant women who underwent genetic amniocentesis (Table III).17-19 All of the neonates were treated after delivery with hepatitis B immunoglobulin and the vaccine series. As shown, none of the 53 infants of surface antigen–positive/e antigen–negative women were carriers. However, 3 (23%) of 13 infants of e antigen–positive mothers were carriers despite active-passive immunization. This 23% failure rate despite treatment seems high but is not significantly different from other studies that have analyzed the failure rate of active-passive immunization in this e antigen–positive high-risk group. In these studies, the failure rate in the neonates who received only one dose of hepatitis B immunoglobulin with the vaccine series ranged from 7% to 18%.2-5, 13 On the basis of the findings of this study and an analysis of the current literature, it would seem that transplacental viral transmission of hepatitis B prior to labor is rare. However, the risk of a genetic amniocentesis 4 to 5 months prior to delivery still raises concern because of fetal exposure to maternal blood. Some studies have suggested that exposure in utero to hepatitis B at an early gestational age is not a risk because the maturity of the fetal liver cannot sustain an infection.17, 20 However, some amniocentesis procedures can result in significant fetal exposure to maternal blood to the point of development of in utero clots. Intrauterine bleeding after amniocentesis for as long as 9 minutes has been recorded.21 Therefore, because in theory the concern for genetic amniocentesis still exists, we recommend that prior to genetic

testing, HBsAg-positive pregnant women be tested for HBeAg status because this group may have a different risk. In addition, using a 22-gauge needle under continuous guidance and avoiding the placenta are also recommended, if feasible. REFERENCES

1. Beasley RP, Hwang LY, Lin CC, Chien CS. Hepatocellular carcinoma and hepatitis B virus. Lancet 1981;2:1129-33. 2. Beasley RP, Hwang LY, Lee GCY, Lan CC, Roan CH, Huang FY, et al. Prevention of perinatally transmitted hepatitis B virus infections with hepatitis B immune globulin and hepatitis B vaccine. Lancet 1983;2:1099-102. 3. Wong VC, Ip HMH, Reesink HW, Lelie PN, Reerink-Brongers EE, Yeung CY, et al. Prevention of the HBsAg carrier state in newborn infants of mothers who are chronic carriers of HBsAg and HBeAg by administration of hepatitis B vaccine and hepatitis B immunoglobulin. Lancet 1984;1:921-6. 4. Lo KJ, Tsai YT, Lee SD, Wu TC, Wang JY, Chen GH, et al. Immunoprophylaxis of infection with hepatitis B virus in infants born to hepatitis B surface antigen-positive carrier mothers. J Infect Dis 1985;152:817-22. 5. Ip HMH, Lelie PN, Wong VC, Kuhns MC, Reesink HW. Prevention of hepatitis B virus carrier state in infants according to maternal serum levels of HBV DNA. Lancet 1989;1:406-9. 6. Sinatra FR, Shah P, Weissman JY, Thomas DW, Merritt RJ, Tong MJ. Perinatal transmitted acute icteric hepatitis B in infants born to hepatitis B surface antigen-positive and anti-hepatitis Be-positive carrier mothers. Pediatrics 1982;70:557-9. 7. American College of Obstetricians and Gynecologists. Viral hepatitis in pregnancy. Washington: The College; 1998. p. 6. Technical Bulletin No.: 248. 8. Towers CV, Chinn DH, Asrat T, Miller EI, Freeman RK. Intraamniotic bleeding following transabdominal amniocentesis. J Matern Fetal Med 1993;2:133-7. 9. Stevenson D, Lin JH, Tong MJ, Marshall GJ. Characteristics of a cell line (Tong/HCC) established from a human hepatocellular carcinoma. Hepatology 1987;7:1291-5. 10. Wong VCW, Lee AKY, Ip HMH. Transmission of hepatitis B antigens from symptom free carrier mothers to the fetus and the infant. BJOG 1980;87:958-65. 11. Lin HH, Lee TY, Chen DS, Sung JL, Ohto H, Etoh T, et al. Transplacental leakage of HBeAg-positive maternal blood as the most likely route in causing intrauterine infection with hepatitis B virus. J Pediatr 1987;111:877-81. 12. Shen HD, Choo KB, Wu TC, Ng HT, Han SH. Hepatitis B virus infection of cord blood leukocytes. J Med Virol 1987;22:211-6. 13. Lee SD, Lo KJ, Tsai YT, Wu JC, Wu TC, Yang ZL, et al. Role of cesarean section in prevention of mother-infant transmission of hepatitis B virus. Lancet 1988;2:833-4. 14. Mitsuda T, Yokota S, Mori T, Ibe M, Ookawa N, Shimizu H, et al. Demonstration of mother-to-infant transmission of hepatitis B virus by means of polymerase chain reaction. Lancet 1989;2: 886-8. 15. Poovorawan Y, Chongsrisawat V, Theamboonlers A, Yano VL. Is there evidence for intrauterine HBV infection in newborns of hepatitis B carrier mothers? Southeast Asian J Trop Med Public Health 1997;28:365-9.

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16. del Canho R, Grosheide PM, Schalm SW, de Vries RRP, Heijtink RA. Failure of neonatal hepatitis B vaccination: the role of HBVDNA levels in hepatitis B carrier mothers and HLA antigens in neonates. J Hepatol 1994;20:483-6. 17. Grosheide PM, Quartero HWP, Schalm SW, Heijtink RA, Christiaens GCML. Early invasive prenatal diagnosis in HBsAg-positive women. Prenat Diagn 1994;14:553-8. 18. Ko TM, Tseng LH, Chang MH, Chen DS, Hsieh FJ, Chuang SM, et al. Amniocentesis in mothers who are hepatitis B virus carriers does not expose the infant to an increased risk of hepatitis B virus infection. Arch Gynecol Obstet 1994;255:25-30. 19. Alexander JM, Ramus R, Jackson G, Sercely B, Wendel GD Jr. Risk of hepatitis B transmission after amniocentesis in chronic hepatitis B carriers. Infect Dis Obstet Gynecol 1999;7:283-6. 20. Neurath AR, Kent SBH, Strick N, Parker K. Identification and chemical synthesis of a host cell receptor binding site on hepatitis B virus. Cell 1986;46:429-36. 21. Chinn DH, Towers CV, Beeman RG, Miller EI. Sonographically demonstrated intra-amniotic hemorrhage following transplacental genetic amniocentesis. J Ultrasound Med 1990;9:495-501.

Editors’ note: This manuscript was revised after these discussions were presented. Discussion DR RUSSELL LAROS, JR, San Francisco, California. Worldwide, hepatitis B virus positivity continues to be a major health care problem, with an estimated 200 million carriers. The impact of being a hepatitis B carrier is immense because of the consequent development of chronic hepatitis, cirrhosis, and primary hepatocellular carcinoma. The recognition that vertical transmission from mother to fetus is a major source of infection radically changed our approach to disease prevention. Universal screening for women who carry hepatitis B virus and the introduction of programs for passive and active immunization for the newborn of an HBV carrier have had a dramatic effect on the rate of vertical transmission. The current approach has reduced the neonatal infection rate to approximately 10%. Why not 0%? Are these failures a result of intrauterine infection, or are they a failure of the postnatal treatment regimen? Dr Towers and his associates have reported the results of a carefully designed study that determined the presence of HBV DNA in cord blood specimens of infants of HBsAg-positive women. As we have just heard, HBV DNA was rarely present in the cord blood studies and was not present in amniotic fluid obtained by amniocentesis during the second or third trimesters of pregnancy. Both Dr Towers’ data and those of other investigators strongly suggest that intrauterine infection prior to labor and delivery is rarely the cause of failures of our current passive and active immunization protocols. His recommendations regarding counseling and the methodology of amniocentesis in HBsAg-positive mothers is pertinent to all of our practices. My questions of Dr Towers do not relate directly to his data; rather, I ask him to share his wisdom with us in the following areas of management of HBsAg-positive mothers: 1. What precautions should we take with respect to the use of fetal scalp electrodes? 2. Does cesarean delivery prior to the onset of labor

June 2001 Am J Obstet Gynecol

lower or increase the risk of failure of our current newborn treatment protocol, and might this change be related to HBeAg status? 3. What are your thoughts about the use of alternative treatment regimens of passive and active immunization in women who are HBeAg positive? Thank you for an excellent study and presentation. DR DALE REISNER, Seattle, Washington. Did you have eantigen status on your patients, especially the 2 who did have positive DNA after delivery? DR ROGER ROWLES, Yakima, Washington. The implication is that contaminated or bloody taps increase the risk of hepatitis transmission. Have any studies actually evaluated that risk, and can they differentiate between genetic amniocenteses and amniocenteses done for fetal lung maturity? DR JOHN NAIDEN, Yakima, Washington. You made a lot of references to HB-e status. Would DNA status be more useful to know, because that is actually measuring viral particles in the bloodstream? Are DNA titers of any use? Ribonucleic acid titers are of some use in predicting outcomes in hepatitis C treatment. DR CRAIG TOWERS, Huntington Beach, California (Closing). In response to Dr Reisner’s question, we did not test every patient in the study for the presence of hepatitis B–e antigen. We did not do this in part because of the recommendations of the American College of Obstetricians and Gynecologists, which state that HBsAG-positive women should be identified and their newborns treated after delivery with a dose of hepatitis B immunoglobulin and the vaccine series regardless of their hepatitis B–e antigen status. In retrospect, not testing every patient for the presence of hepatitis B–e antigen was somewhat of a flaw in our study, and I wish we had obtained a result in every case. Of the 3 women who had cord blood that was DNA positive, 2 were e-antigen positive. In the third case, the e-antigen status was not determined. The majority of the money that was granted for the performance of this study went to performing the DNA probes. When we were reviewing the literature, we discovered something interesting regarding treatment of neonates of hepatitis B–e antigen–positive pregnant women that pertains to one of the questions posed by Dr Laros. In the studies that analyzed the development of hepatitis B infection in newborns despite treatment after delivery with immunoglobulin and the vaccine series in e-antigen positive carrier women, the neonates who received more than one dose of hepatitis B immunoglobulin following delivery seemed to have slightly lower failure rates compared with the singledose group. However, within these studies, the differences were not statistically significant.1-7 On the other hand, if these studies are combined (see Table I), the failure rate of the multidose group is more than 50% lower than the single-dose group, and this difference is significant at P < .002 (95% CI of 0.15-0.68). This information suggests that if a high inoculum of hepatitis B DNA is transmitted to the neonate at the time of delivery, a single dose of hepatitis B immunoglobulin may

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Table I. Failure rate of active-passive immunization of the neonate after delivery from HBsAg-positive, HBeAg-positive carrier mothers on basis of number of hepatitis B immunoglobulin treatments administered in conjunction with vaccine series Study*

No. of cases with 1 HBIg dose

No. of failures (%)

No. of cases with >1 HBIg dose

No. of failures (%)

Beasely et al,1 1983 Wong et al,2 1984 Lo et al,3 1985 Chung et al,4 1985 Stevens et al,5 1985 Kanai et al,6 1985 Ip et al,7 1989

108 35 75 29 113

8 (7) 3 (9) 8 (11) 4 (14) 16 (14)

51 36 37

1 (2) 1 (3) 3 (8)

64 424

9 (14) 48 (11)

50 60 234

0 (0) 4 (7) 9 (4)†

TOTAL

HBIg, Hepatitis B immunoglobulin. *Studies analyzed more than 20 patients in a group, and newborns were evaluated beyond 6 months of life. †P < .002 (95% confidence interval of .15, .68).

not be sufficient. This in theory is similar to the need for more than one dose of Rhogam required to adequately treat an Rh-negative mother who is exposed to more than 30 mL of Rh-positive fetal blood. The development of antibody to hepatitis B surface antigen following vaccine treatment takes time and will not treat an acute exposure. Immunoglobulin therapy is indicated in the management of an acute exposure. Vaccine therapy is helpful for long-term immunity. Because these studies were performed in different countries and different protocols were used for immunoglobulin therapy and vaccine treatment, as well as different dosages of immunoglobulin, combining these studies may not result in a fair comparison. Therefore, I suggest that a collaborative Pacific Coast study be developed to evaluate whether more than one dose of hepatitis B immunoglobulin is needed in the treatment of neonates of HBeAg-positive carrier mothers. With regard to the question about cesarean delivery before labor, Dr Lee and colleagues8 actually examined this phenomenon in one study. They did DNA testing on cord blood of neonates delivered by cesarean versus those delivered vaginally. They found no DNA in the cord blood of the newborns delivered by cesarean versus a 19% positive rate for those delivered vaginally, which again suggests that it is the process of labor that allows for the transplacental transmission of the hepatitis B virus. However, for hepatitis B, we have a very effective immunoglobulin and vaccine, and therefore neonates can be treated after delivery with good results, and routine cesarean delivery would not be indicated on the basis of viral status alone. We have to remember that a cesarean delivery does not prevent exposure to the baby of maternal bodily fluids, it only decreases the duration of exposure. In addition, if it is performed prior to the onset of labor, a cesarean delivery eliminates the issue of contractions. Regarding Dr Laros’s question, I would say that most of us do not worry about scalp electrodes because we plan to treat the baby with immunoglobulin and vaccine after delivery. However, I would argue that if the mother is eantigen positive, use of scalp electrodes might increase

the risk of viral exposure, and I would recommend using an external monitor whenever possible. If an internal monitor is necessary, it might be prudent to consider administering a second dose of immunoglobulin within 7 to 14 days after the first injection in cases in which the mother is e-antigen positive. Regarding Dr Rowles’ question about whether bloody taps increase the risk, I have 2 answers. If your question pertains to the color of the fluid, my reply is that we wanted to ensure that the amniotic fluid tested was not contaminated with maternal blood, because this contamination could adversely affect the results and implications of the study. If the question relates to bleeding in utero following the amniocentesis, I would say in theory that any time a large inoculum of blood or any substance that contains a virus is present, there is a risk of transmitting that virus to the newborn before delivery. In response to Dr Naiden’s question about testing women for hepatitis B DNA and performing titers, I believe that could be done; however, currently these DNA tests are performed only in specific research laboratories. Not very many laboratories with this testing capability exist across the United States; in addition, the testing is fairly expensive and takes a certain amount of time and expertise to perform. Not until those tests become rapid, simple, and inexpensive do I think they would replace the current surface antigen and e-antigen testing. REFERENCES

1. Beasley RP, Hwang LY, Lee GCY, Lan CC, Roan CH, Huang FY, et al. Prevention of perinatally transmitted hepatitis B virus infections with hepatitis B immune globulin and hepatitis B vaccine. Lancet 1983;2:1099-102. 2. Wong VC, Ip HMH, Reesink HW, Lelie PN, Reerink-Brongers EE, Yeung CY, et al. Prevention of the HBsAg carrier state in newborn infants of mothers who are chronic carriers of HBsAg and HBeAg by administration of hepatitis B vaccine and hepatitis B immunoglobulin. Lancet 1984;1:921-6. 3. Lo KJ, Tsai YT, Lee SD, Wu TC, Wang JY, Chen GH, et al. Immunoprophylaxis of infection with hepatitis B virus in infants born to hepatitis B surface antigen-positive carrier mothers. J Infect Dis 1985;152:817-22. 4. Chung WK, Yoo JY, Sun HS, Lee HY, Lee IJ, Kim SM, et al. Prevention of perinatal transmission of hepatitis B virus: a compari-

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son between efficacy of passive and passive-active immunization in Korea. J Infect Dis 1985;151:280-6. 5. Stevens CE, Toy PT, Tong MJ, Taylor PE, Vyas GN, Nair PV, et al. Perinatal hepatitis B transmission in the United States. JAMA 1985;253:1740-5. 6. Kanai K, Takehiro A, Noto H, Nishida M, Takahashi K, Kawashima Y, et al. Prevention of perinatal transmission of hepatitis B virus (HBV) to children of e antigen-positive HBV carrier

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mothers by hepatitis B immune globulin and HBV vaccine. J Infect Dis 1985;151:287-90. 7. Ip HMH, Lelie PN, Wong VC, Kuhns MC, Reesink HW. Prevention of hepatitis B virus carrier state in infants according to maternal serum levels of HBV DNA. Lancet 1989;1:406-9. 8. Lee SD, Lo KJ, Tsai YT, Wu JC, Wu TC, Yang ZL, et al. Role of cesarean section in prevention of mother-infant transmission of hepatitis B virus. Lancet 1988;2:833-4.

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