Obstetricians’ and gynecologists’ knowledge, education, and practices regarding chronic hepatitis B in pregnancy

Introduction

Between 800,000 and 1.4 million people in the United States are infected with the hepatitis B virus (HBV) [1]. HBV is a major risk factor for hepatocellular carcinoma, leading to 50% of cases worldwide. There is an estimated prevalence of 0.7-0.9% of chronic HBV among pregnant women in the US, with >25,000 neonates at risk for chronic infection annually [2,3].

Obstetricians and gynecologists (OB-GYNs) perform a key role in the prevention of mother-to-child transmission (MTCT). To provide optimal care of pregnant women who are HBV carriers, OB-GYNs need appropriate knowledge, education, and practice in the management of these patients.

The Centers for Disease Control and Prevention and the American College of OB-GYNs (ACOG) have both published recommendations for screening for HBV among pregnant women [5], calling for hepatitis B surface antigen (HBsAg) as the initial serological testing for all pregnant women, followed by hepatitis B e-antigen (HBeAg), HBV DNA viral load, and alanine aminotransferase (ALT). If HBeAg is positive, HBV DNA >20,000 IU/mL, or ALT ≥19 IU/L, then the patient should be referred to a specialist immediately during pregnancy.

The 2016 American Association for the Study of Liver Diseases (AASLD) guidelines suggest antiviral therapy to reduce the risk of perinatal transmission of hepatitis B in pregnant women with an HBV DNA level >200,000 IU/mL (>1 million copies/mL) [4]. The 2016 Society for Maternal-Fetal Medicine consensus recommends third-trimester HBV viral load testing and antiviral therapy over a greater range of viral load (HBV DNA >1 million to 100 million copies/mL) compared to the AASLD recommendation.

The current survey aimed to determine the knowledge, education, and practices of OB-GYNs regarding HBV in pregnant women. In addition, we determined referral patterns and thresholds for OB-GYNs to treat patients with HBV.

Materials and methods

Results

Characteristics of responders

A total of 323 participants from ACGME-accredited OB-GYN residency programs across the US responded to the survey (Table 1). The respondents included both PDs (n=51, response rate of 21%) and residents (n=272, response rate of 11%). The responding resident cohort exhibited a diversity of experience, with equal distribution across postgraduate years (PGY) of training. Responding PDs came from varied practice settings, including university-based (62%), community-based (32%), and military-based (6%).

Table 1 Characteristics of responding PDs and residents

Practice patterns and peripartum management

All PDs and 95.2% of residents reported screening for chronic HBV in pregnant patients on the first prenatal visit. Referral patterns showed that 66.7% of PDs and 65.5% of residents referred to a specialist regardless of viral load. A minority of respondents (19.6% PD, 12.6% residents) knew that third-trimester antiviral therapy is recommended for women with high viral loads (>1 million copies/mL or 200,000 IU/mL). Few respondents had prescribed antivirals for HBV (9.8% PD, 6.0% residents). Residents more commonly prescribed tenofovir (75%) and less frequently lamivudine (16.7%). In contrast, more PDs prescribed lamivudine (60%) and fewer tenofovir (40%). Furthermore, most PDs (98%) and residents (83.1%) disagreed that HBV was an indication for Cesarean section (C-section) (Table 2).

Table 2 Summary of selected survey responses from PDs and residents

Education and interpretation of HBV serologies

Half of PDs believed residents from their programs were comfortable in managing HBV in pregnancy, but only 41.8% of residents reported being comfortable managing these patients (Table 2). Only 23.5% of training programs have dedicated teaching about HBV in pregnancy. With respect to years of training, the percentage of residents who felt comfortable managing HBV increased with post-graduate year: PGY 1 (22%), PGY 2 (28%), PGY 3 (42%), and PGY 4 (69%) (Fig. 1). A majority of PDs and residents interpreted HBV serologies correctly (Table 3).

Figure 1 Resident responses to “I feel comfortable managing pregnant patients with chronic hepatitis B” across post-graduate years (PGY)

Table 3 Interpretations of HBV serologies

Discussion

Because screening based on risk factors alone will miss many cases of HBV, universal screening for HBV during pregnancy at the first prenatal visit has been recommended by the ACOG and the US Preventative Services Task Force for many years [5]. In our study, all PDs and over 95% of residents screened for HBV appropriately at the first prenatal visit.

Despite appropriate screening, significant gaps exist in residents’ comfort and education in the management of pregnant patients with HBV, though improvement is seen as they progress through years of training. Even in their last year of training, only 69% of PGY-4 residents felt comfortable managing a pregnant patient with HBV. This may be related to a lack of clinical exposure, with less than half of residents reporting an adequate amount of clinical exposure to HBV patients. In addition, less than a quarter of programs offer a didactic session on HBV. Better educational initiatives could potentially decrease MTCT rates further.

Maternal infection with HBV is a major cause of MTCT [6]. A recent study found that a maternal HBV DNA level >1 million copies/mL at delivery is the most important predictor of in utero MTCT and hepatitis B immune globulin prophylaxis failure [7]. The newest guideline from the Society for Maternal-Fetal Medicine recommends third-trimester HBV viral load testing and antiviral therapy if viral load is >6-8 log 10 (1 million to 100 million) copies/mL [8]. In 2012-2013, the European Association for the Study of the Liver and the United Kingdom’s National Institute for Health and Care Excellence have published similar guidelines, recommending treatment in those with HBV viral load >6-7 log 10 (1 million to 10 million) copies/mL [9,10].

With respect to the choice of antiviral therapy, the American Association for the Study of Liver Diseases’ revised guidelines in 2009 for the treatment of chronic HBV call for tenofovir and entecavir to be first-line agents, with lamivudine no longer a first-line agent as there has been concern about resistance [11]. Tenofovir has been shown to be associated with no increase in congenital abnormalities or differences in infant growth parameters at birth compared to an untreated control group [12]. The newest guideline from the Society for Maternal-Fetal Medicine recommends tenofovir as a first-line agent in pregnant women who are candidates for antiviral therapy [8]. Interestingly, a majority of PDs who have prescribed antivirals selected lamivudine as their agent of choice, while the majority of residents selected tenofovir. It is likely that the new guidelines have been disseminated faster to those who are currently in training.

Perinatal HBV infection occurs when the infant comes into contact with vaginal blood and secretions during delivery. A Chinese systemic review that included 789 patients showed a significant decrease in vertical transmission associated with elective C-section (10.5%) compared to vaginal delivery (28.0%) [13]. However, that review included many studies that did not report maternal HBV DNA viral load. Currently, the OB-GYN literature does not support chronic HBV as an indication for C-section [8]. The majority of PDs and residents in our survey reported similar opinions regarding C-section.

Although we surveyed PDs and residents in the entire US, the major limitations of our study include the recall bias inherent in survey studies and the slightly low response rates. We elected to survey PDs as representative of physicians in practice. However, this may not be accurate, as PDs are perhaps more knowledgeable about changing guidelines than are their non-teaching colleagues.

Overall, despite excellent self-reported screening for hepatitis B in pregnant women, OB-GYN knowledge and education regarding management, especially in patients with higher viral loads during the third trimester, is still lacking. Improvement in education and dissemination of guidelines can further decrease vertical transmission in this vulnerable population.