An algorithm for risk assessment and intervention of mother to child transmission of hepatitis B virus

Management of hepatitis B during pregnancy

Chronic HBV infection is estimated to affect >350 million people worldwide and represents a substantial source of morbidity and mortality related to cirrhosis and hepatocellular carcinoma. Mother-to-child transmission (MTCT) remains an important source of incident cases of hepatitis B. Immunoprophylaxis of infants born to mothers who are positive for hepatitis B surface antigen is used to prevent MTCT; however, under-utilization of this intervention in certain regions endemic for HBV infection and failure of immunoprophylaxis in 5-10% of cases are barriers to preventing HBV transmission via this route. Data suggest that a high level of HBV viraemia in pregnant women is a substantial risk factor for immunoprophylaxis failure. Potential means of reducing viral load include antiviral therapy in the third trimester to reduce exposure of the neonate to the virus. Determining the optimal time to treat active HBV-related liver disease in women who wish to become pregnant, as well as managing antiviral therapy in patients who become pregnant, remains challenging. Owing to the vulnerable population affected by these issues, clinical trials are difficult and, thus, evidence-based recommendations are limited. Emerging data are addressing management of HBV during pregnancy that health-care providers should be made aware of. Here, we provide an overview of issues pertinent to HBV infection during pregnancy and present a management algorithm.

Prevention of materno-foetal transmission of hepatitis B in sub-Saharan Africa: the evidence, current practice and future challenges

Hepatitis B (HBV) infection is highly endemic in sub-Saharan Africa (SSA), where more than 8% of the population remain chronic HBV carriers. SSA has one of the highest HBV-related liver cancer rates in the world (CA Cancer J Clin, 55, 2005, 74) and HBV-related liver cancer is the most common cause of premature death in West Africa (Lancet Oncol, 9, 2008, 683; Hepatology, 39, 2004, 211). As such, HBV represents a significant global threat to health in the African continent. Most SSA countries have elected to vaccinate all children against HBV through the WHO-sponsored Expanded Program of Immunization and the current recommendation from WHO-AFRO is for birth-dose HBV vaccination to prevent maternal/child transmission (MFT) and early horizontal transmission of HBV. However, in Africa, HBV vaccine coverage remains low and HBV birth-dose vaccination has not been implemented. HBV transmission from mother to child in the early perinatal period therefore remains a significant contributor to the burden of HBV-related disease in SSA. This review explores the evidence for materno-foetal transmission of HBV in SSA, outlining current practice for HBV MFT prevention and identifying the significant challenges to implementation of HBV prevention in SSA.

Current recommendations of managing HBV infection in preconception or pregnancy

Hepatitis B remains a leading cause of cirrhosis, hepatocellular carcinoma and liver transplantation worldwide. Management of chronic hepatitis B during pregnancy is challenging. Transmission of hepatitis B to infants still occurs perinatally although immunoprophylaxis is widely available for infants born to mothers with chronic hepatitis B infection. The emerging data suggest that initiation of antiviral therapy in the beginning of the third trimester in highly viremic mothers can prevent immunoprophylaxis failure in their infants. The available drug safety data show that lamivudine, telbivudine and tenofovir are generally safe to be used during the pregnancy. In order to minimize the fetal exposure to the antiviral medication, antiviral therapy during the pregnancy should be limited to a selected group of patients with cirrhosis, high hepatitis B viral load, or prior history immunoprophylaxis failure. An elective Caesarean section may reduce the risk of perinatal transmission. For those females planning for pregnancy or in early stage of pregnancy, communication and follow-up among obstetrician, gastroenterologist, and primary care physician are important. In this article, we will review the features of hepatitis B infection before, during and after the pregnancy; the risk factors that increase mother-to-child transmission; safety data on antiviral drug use during pregnancy; and the potential role of Caesarean section in selected cases.

Cost-effectiveness of testing hepatitis B-positive pregnant women for hepatitis B e antigen or viral load

OBJECTIVE

To estimate the cost-effectiveness of testing pregnant women with hepatitis B (hepatitis B surface antigen [HBsAg]-positive) for hepatitis B e antigen (HBeAg) or hepatitis B virus (HBV) DNA, and administering maternal antiviral prophylaxis if indicated, to decrease breakthrough perinatal HBV transmission from the U.S. health care perspective.

METHODS

A Markov decision model was constructed for a 2010 birth cohort of 4 million neonates to estimate the cost-effectiveness of two strategies: testing HBsAg-positive pregnant women for 1) HBeAg or 2) HBV load. Maternal antiviral prophylaxis is given from 28 weeks of gestation through 4 weeks postpartum when HBeAg is positive or HBV load is high (10 copies/mL or greater). These strategies were compared with the current recommendation. All neonates born to HBsAg-positive women received recommended active-passive immunoprophylaxis. Effects were measured in quality-adjusted life-years (QALYs) and all costs were in 2010 U.S. dollars.

RESULTS

The HBeAg testing strategy saved $3.3 million and 3,080 QALYs and prevented 486 chronic HBV infections compared with the current recommendation. The HBV load testing strategy cost $3 million more than current recommendation, saved 2,080 QALYs, and prevented 324 chronic infections with an incremental cost-effectiveness ratio of $1,583 per QALY saved compared with the current recommendations. The results remained robust over a wide range of assumptions.

CONCLUSION

Testing HBsAg-positive pregnant women for HBeAg or HBV load followed by maternal antiviral prophylaxis if HBeAg-positive or high viral load to reduce perinatal hepatitis B transmission in the United States is cost-effective.

Risk of vertical transmission of hepatitis B after amniocentesis in HBs antigen-positive mothers

BACKGROUND & AIMS

Despite appropriate immunoprophylaxis, HBV vertical transmission (VT) occurs in 5-10% of infants born to HBs-antigen (HBsAg)+ mothers. We investigated whether amniocentesis increases the risk of transmission.

METHODS

We performed a case-control study on infants who were born to HBsAg+ mothers without antiviral exposure and completed appropriate immunization. Infants born to mothers with amniocentesis were compared to those without amniocentesis to assess VT rates, which were defined by the percentage of infants with HBsAg positivity when they were 7-12 months old.

RESULTS

Of the 642 consecutive infants enrolled, 63 infants with amniocentesis were compared with 198 matched infants selected from the remaining 579 infants without amniocentesis. There was a higher VT rate in infants with amniocentesis than in those without amniocentesis (6.35% vs. 2.53%; p=0.226). Maternal HBV DNA levels before amniocentesis were further stratified to <500 copies/ml, 500-6.99 log10 copies/ml, and ⩾ 7 log10 copies/ml for subset analyses. There were no significant differences in the VT rates between the amniocentesis group and the control group if the maternal HBV DNA levels were <6.99 log10 copies/ml. However, a significantly higher VT rate was observed in the amniocentesis group vs. the control group if the maternal HBV DNA levels were ⩾ 7 log10 copies/ml (50% vs. 4.5%, respectively, p=0.006). According to baseline value risk analyses, performing amniocentesis on highly viremic mothers was a risk factor for HBV transmission (OR=21.3, 95% CI: 2.960-153.775).

CONCLUSIONS

Amniocentesis performed on HBsAg+ mothers with HBV DNA ⩾ 7 log10 copies/ml significantly increased the frequency of VT. HBsAg+ women who plan to have amniocentesis should be evaluated for the risk of VT and stratified according to their HBV DNA levels. Further prospective studies are warranted to verify our findings.

Telbivudine or lamivudine use in late pregnancy safely reduces perinatal transmission of hepatitis B virus in real-life practice

Little observational data exist describing telbivudine (LdT) or lamivudine (LAM) use in late pregnancy for preventing hepatitis B mother-to-child transmission (MTCT) in real-world settings. During the period of January 2009 to March 2011, we enrolled hepatitis B e antigen-positive mothers with HBV DNA >6 log10 copies/mL in China. At gestation week 28, the mothers received LdT or LAM until postpartum week 4 or no treatment (NTx). The study endpoints were the safety of LdT/LAM use and MTCT rates. Of the 700 mothers enrolled, 648 (LdT/LAM/NTx = 252/51/345) completed the 52-week study with 661 infants (LdT/LAM/NTx = 257/52/352). On treatment, viral rebound occurred in 1.6% of mothers, all resulting from medication noncompliance. There was no genotypic mutation detected. At delivery, significantly lower HBV DNA levels were noted in mothers who received LdT or LAM versus NTx. Alanine aminotransferase flares were observed in 17.1% of treated mothers versus 6.3% of untreated mothers (P < 0.001). At birth, hepatitis B surface antigen (HBsAg) was detected in 20% and 24% of newborns in the treated and NTx groups, respectively. At week 52, an intention-to-treat analysis indicated 2.2% (95% confidence [CI]: 0.6-3.8) of HBsAg+ infants from the treated group versus 7.6% (95% CI: 4.9-10.3) in the NTx group (P = 0.001) and no difference of HBsAg+ rate between infants in the LdT and LAM groups (1.9% vs. 3.7%; P = 0.758). On-treatment analysis indicated 0% of HBsAg+ infants in the treated group versus 2.84% in the NTx group (P = 0.002). There were no differences for gestational age or infants' height, weight, Apgar scores, or birth defect rates between infants from the treated and untreated groups. Conclusions: LdT and LAM use in late pregnancy for highly viremic mothers was equally effective in reducing MTCT. The treatment was well tolerated with no safety concerns identified. (Hepatology 2014).

Interpretation and management of hepatic abnormalities in pregnancy

The spectrum of liver disease in pregnancy includes liver disease unrelated to pregnancy, liver diseases that occur with increased frequency or severity in pregnancy, and liver disease specific to pregnancy. Diseases of the liver unique to pregnancy reliably occur at specific points in the gestational spectrum. Thus, gestational age, a comprehensive history, and a clinically driven diagnostic evaluation is critical in approaching a pregnant patient with abnormal liver chemistries or function. Early recognition of these conditions is important and although management may be expectant, some patients require targeted therapy or necessitate prompt delivery, which can be life-saving to both mother and child.

Cesarean section reduces perinatal transmission of hepatitis B virus infection from hepatitis B surface antigen-positive women to their infants

BACKGROUND & AIMS

Despite appropriate passive and active immunization, perinatal transmission of hepatitis B virus (HBV) still occurs in 5%-10% of infants born to women with high levels of viremia who test positive for the hepatitis B e antigen (HBeAg). We evaluated the effects of cesarean section delivery on perinatal transmission of HBV from women who tested positive for the hepatitis B surface antigen (HBsAg).

METHODS

We analyzed data from 1409 infants born to HBsAg-positive mothers through vaginal delivery (VD) (n = 673), elective caesarean section (ECS) (n = 496), or urgent cesarean section (UCS) (n = 240) who completed appropriate immunization against HBV. The prevention was assumed to have failed for infants who were HBsAg positive when they were 7-12 months old; this information was used to assess transmission rates.

RESULTS

HBV infection was transmitted to a smaller percentage of infants born by ECS (1.4%) than by VD (3.4%, P < .032) or UCS (4.2%, P < .020). UCS had no effect on vertical transmission, compared with VD (4.2% vs 3.4%, P = .593). Infants born by ECS had a significantly lower rate of vertical transmission than those born by non-ECS (1.4% vs 3.6%, P = .017). Women with HBV DNA levels <1,000,000 copies/mL did not transmit the infection to their infants, regardless of method of delivery. There were no differences in maternal or infant morbidity and mortality among the groups.

CONCLUSIONS

There is a significantly lower rate of vertical transmission of HBV infection to infants delivered by ECS, compared with those delivered vaginally or by UCS. Elective cesarean sections for HBeAg-positive mothers with pre-delivery levels of HBV DNA ≥1,000,000 copies/mL could reduce vertical transmission.

Analysis of residual perinatal transmission of hepatitis B virus (HBV) and of genetic variants in human immunodeficiency virus and HBV co-infected women and their offspring

BACKGROUND

Despite implementation of universal infant hepatitis B (HB) vaccination, mother-to-child transmission (MTCT) of hepatitis B virus (HBV) still occurs. Limited data are available on the residual MTCT of HBV in human immunodeficiency virus (HIV)-HBV co-infected women.

OBJECTIVES

We assessed the prevalence of HBV infection among HIV-infected pregnant women and the rate of residual MTCT of HBV from HIV-HBV co-infected women and analyzed the viral determinants in mothers and their HBV-infected children.

STUDY DESIGN

HIV-1 infected pregnant women enrolled in two nationwide perinatal HIV prevention trials in Thailand were screened for HB surface antigen (HBsAg) and tested for HBeAg and HBV DNA load. Infants born to HBsAg-positive women had HBsAg and HBV DNA tested at 4-6 months. HBV diversity within each HBV-infected mother-infant pair was analyzed by direct sequencing of amplified HBsAg-encoding gene and cloning of amplified products.

RESULTS

Among 3312 HIV-1 infected pregnant women, 245 (7.4%) were HBsAg-positive, of whom 125 were HBeAg-positive. Of 230 evaluable infants born to HBsAg-positive women, 11 (4.8%) were found HBsAg and HBV DNA positive at 4-6 months; 8 were born to HBeAg-positive mothers. HBV genetic analysis was performed in 9 mother-infant pairs and showed that 5 infants were infected with maternal HBV variants harboring mutations within the HBsAg "a" determinant, and four were infected with wild-type HBV present in highly viremic mothers.

CONCLUSIONS

HBV-MTCT still occurs when women have high HBV DNA load and/or are infected with HBV variants. Additional interventions targeting highly viremic women are thus needed to reduce further HBV-MTCT.

Mother-to-infant transmission of hepatitis B virus infection: significance of maternal viral load and strategies for intervention

BACKGROUND & AIMS

Immunoprophylaxis reduces but does not completely eradicate hepatitis B virus (HBV) transmission. This prospective study aims at assessing the rate and risk factors of maternally transmitted HBV infection.

METHODS

We enrolled 303 mother-infant pairs with positive maternal hepatitis B surface antigen (HBsAg) under current immunization program. Maternal viral load was determined by a real-time PCR-based assay. The children were tested for HBsAg at 4-8 months and/or 1-3 years of age. Rates of HBV infection were estimated using a multivariate logistic regression model.

RESULTS

HBeAg-positive mothers (81/303, 26.7%) had higher viral loads than HBeAg-negative mothers (7.4 ± 1.9 vs. 2.7 ± 1.4 log10 copies/ml, p<0.0001). Ten children, born to HBeAg-positive mothers with high viral load (median, 8.4; range, 6.5-9.5 log₁₀ copies/ml), were chronically infected. After adjustment for maternal age, birth type, factors related to maternal-fetal hemorrhage, gestational age, infant gender, birth weight, timeliness of vaccination, and feeding practice, maternal viral load was significantly associated with risk of infection (adjusted odds ratio for each log₁₀ copy/ml increase, 3.49; 95% confidence interval (CI), 1.63-7.48; p=0.001). The predictive rates of infection at maternal viral load levels of 7, 8, and 9 log₁₀ copies/ml were 6.6% (95% CI, 0.5-12.6%; p=0.033), 14.6% (95% CI, 5.6-23.6%; p=0.001), and 27.7% (95% CI, 13.1-42.4%; p<0.001), respectively.

CONCLUSIONS

Additional strategies to further reduce transmission should be considered in mothers with a viral load above 7-8 log₁₀ copies/ml.

Effect of elective cesarean section on the risk of mother-to-child transmission of hepatitis B virus

Background

Many clinicians and hepatitis B virus (HBV)-infected pregnant women prefer elective caesarean section (ECS) to prevent mother-to-child transmission of HBV, since some studies found higher transmission of HBV in infants born by vaginal delivery (VD) than by cesarean section. However, other studies showed that ECS does not reduce the risk of being infected with HBV in infants. In this study, we aimed to clarify whether ECS may reduce the risk of mother-to-child transmission of HBV.

Methods

Totally 546 children (1–7-year-old) born to 544 HBsAg-positive mothers from 15 cities and rural areas across Jiangsu Province, China, were enrolled. Of these children, 137 (2 pairs of twins) were born to HBeAg-positive mothers; 285 were delivered by ECS and 261 others by VD (one pair of twin in each group). HBV serologic markers were tested by enzyme or microparticle immunoassay.

Results

The maternal and gestational ages, maternal HBeAg-positive rates, and children’s ages, gender ratios, hepatitis B vaccine coverage and administrations of HBIG were comparable between ECS and VD groups (all p >0.05). The overall prevalence of HBsAg in the 546 children was 2.4%, with 2.5% (7/285) and 2.3% (6/261) in those born by ECS and VD respectively (p = 0.904). Further comparison of chronic HBV infection in the 137 children of HBeAg-positive mothers showed that the HBsAg-positive rates in ECS and VD groups were 10.3% (7/68) and 8.7% (6/69) respectively (p = 0.750), while the mothers had similar HBV DNA levels (2.38 × 10⁶ vs. 2.35 × 10⁶ IU/ml, p = 0.586). Additionally, the overall rate of anti-HBs ≥10 mIU/ml in the children was 71.6%, with 72.3% and 70.9% in those born by ECS and VD respectively (p = 0.717).

Conclusions

With the recommended immunoprophylaxis against hepatitis B, ECS does not reduce the risk of mother-to-child transmission of HBV. Therefore, ECS should not be used in HBsAg-positive pregnant women to prevent mother-to-child transmission of HBV.

A pregnant woman with acute hepatitis B in whom vertical transmission was prevented by tenofovir disoproxil fumarate

The optimal management of acute hepatitis B in pregnant women remains to be fully evaluated. A case of hepatitis B virus (HBV) infection in a 20-year-old pregnant woman who initially presented with jaundice is reported. Serum samples were positive for anti-HBc IgM and HBe antigen. Her husband was infected with HBV genotype A and received entecavir because of prolonged hepatitis and a high viral load. The HBV DNA sequence of the wife completely matched that of her husband, indicating that he was the source of HBV infection. In accordance with guidelines for the treatment of chronic HBV carriers, the wife started to receive tenofovir disoproxil fumarate (TDF) in her third trimester. After 4 months of treatment, the HBV DNA load decreased from 7.6 to 3.5 log copies/ml. At delivery, the serum was found negative for the HBe antigen. Seven months after treatment began, the HBs antigens also disappeared. The baby, totally healthy, received passive-active immunoprophylaxis. At 3 months, the baby remained free of HBV infection. TDF thus prevented exacerbation and prolongation of acute HBV infection in a pregnant woman. Subsequent treatment also prevented mother-to-infant transmission of HBV. The clinical course of her husband, who had HBV infection and received entecavir, is also reported.

Optimal management of HBV infection during pregnancy

Chronic hepatitis B virus (HBV) infection in pregnancy presents a unique and important challenge. Over 50% of chronic HBV carriers in endemic areas acquire infection vertically from their mothers. More importantly, over 90% of perinatally acquired infections progress to chronic HBV infection. Thus, management of chronic HBV during pregnancy and strategies to prevent mother-to-child transmission is an important step in eradicating or reducing the global burden of chronic hepatitis B. In addition, chronic HBV infection in pregnancy presents a unique clinical challenge because of the complex relationship between the physiological changes of pregnancy and the pathophysiological response to HBV. This review will present the current knowledge and a practical approach to management of HBV in pregnancy.

Telbivudine prevents vertical transmission from HBeAg-positive women with chronic hepatitis B

BACKGROUND & AIMS

Telbivudine reduces hepatitis B virus (HBV) DNA and normalizes levels of alanine aminotransferase (ALT) in patients with chronic hepatitis B (CHB). We investigated its use in preventing vertical transmission.

METHODS

We performed an open-label, prospective study of 88 hepatitis B (HB) e antigen (HBeAg)-positive pregnant women with CHB, levels of HBV DNA >6 log(10) copies/mL, and increased levels of ALT. Women were given telbivudine (n = 53) starting in the 2nd or 3rd trimester, or no treatment (controls, n = 35) and followed until postpartum week (PPW) 28. All infants received standard immunoprophylaxis after birth.

RESULTS

At 28 weeks, none of the infants whose mothers received telbivudine had immunoprophylaxis failure, whereas 8.6% of the infants of control mothers did (P = .029). There were no differences between groups in mothers' adverse events or infants' congenital deformities, gestational age, height, and weight, or Apgar scores. At postpartum week 28, significantly more telbivudine-treated mothers had levels of HBV DNA <500 copies/mL, normalized levels of ALT, and hepatitis B e antigen seroconversion compared with controls (58% vs none, P < .001; 92% vs 71%; P = .008; and 15% vs none; P < .001, respectively) but none had loss of hepatitis B surface antigen. Telbivudine-treated mothers had no virologic breakthrough (HBV DNA >1 log(10) increase from <500 copies/mL) or discontinuations from adverse events. After delivery, 13/52 patients discontinued telbivudine due to preference. There were no episodes of severe hepatitis (levels of ALT >10 times the upper limit of normal) in either group during 28 weeks of postpartum observation.

CONCLUSIONS

Women with CHB given telbivudine during the second or third trimester of pregnancy have reduced rates of perinatal transmission. Telbivudine produced no adverse events in mothers or infants by 28 weeks.