Mother-to-child transmission (MTCT) is responsible for the majority of hepatitis B virus (HBV) infections worldwide. While timely vaccinations at birth can reduce MTCT, immunization failures can still occur in infants born to mothers with high levels of HBV in the blood. Moreover, many infected individuals do not know their status. Working with a large Asian American immigrant population where 13% of adults have been screened with chronic HBV, the Charles B. Wang Community Health Center conducted this study to understand the scope of mother-to child transmission risk of HBV.
In this study, the researchers assessed the demographics, clinical characteristics, and MTCT risk in Asian American women with chronic HBV who received prenatal care from 2007-2017 at two community health center sites in New York City. Those included in the study were: female patients aged 18 years and older with at least one prenatal visit, a positive HBV surface antigen test, and an HBV DNA test result during pregnancy. The investigators also collected the following demographic characteristics: age, insurance, education, occupation, birth region, and years in the U.S.
Both the demographic and clinical characteristics were categorized by the patient’s HBV disease phases, as defined in the 2018 American Association for the Study of Liver Diseases (AASLD). They were then analyzed for factors associated with high transmission risk. This risk was defined as having an HBV DNA level (HBV activity or replication in the liver) greater than 200,000 IU/mL, which is designated by the dotted line on the following graph:
The graph illustrates the 1,241 pregnancies among female patients who were not on antiviral treatment at the time of their initial HBV evaluation. ALT reflects liver inflammation and HBV DNA level reflects the amount of HBV activity or replication in the liver.
Of these pregnancies, results show that:
- 22.4% of them were considered high-risk for mother-to-child transmission
- Of the 22.4%, about 92% were HBV e antigen (HBeAg) positive and 6.8% were HBeAg negative
- HBeAg positive status and liver inflammation (elevated ALT) were associated with higher likelihood for being high-risk for mother-to-child transmission. This is evident by the number of green data points located above the dotted line which represents the HBV DNA level at which mothers are at risk of transmitting HBV to their infants.
- It is important to note that the 6.8% of patients who were HBeAg negative were also considered high-risk for mother-to-child transmission.
This study can help inform front-line providers about the importance of evaluating for and treating high viral load in pregnant women in order to reduce the risk of mother-to-child transmission of HBV. It also suggests that HBV DNA testing is still an important test for pregnant patients regardless of their HBeAg status (i.e., positive or negative). In order to prevent mother-to-child transmission during pregnancy, it is vital that front-line providers evaluate and deliver full assessments, interventions, and early coordinated care for pregnant women with chronic HBV.
At the Charles B. Wang Community Health Center, all mothers with chronic HBV are educated by an HBV care manager and linked to comprehensive care during pregnancy. They meet with an on-site primary care provider or an off-site provider for initial HBV evaluation. The Health Center also strives to use creative practices to educate patients and pregnant mothers about hepatitis B. Such examples include a bilingual HBV road map and vaccine tracker for their baby and a hepatitis B comic book that was a recipient of the Materials Contest Award during the American Public Health Association Meeting and Expo in November 2018.
This research was conducted by Dr. Amy Tang, Janice Lyu, Angel Chen, and Qingqing He at Charles B. Wang Community Health Center; Dr. Su Wang at Saint Barnabas Medical Center, and Dr. Calvin Q. Pan at New York University Langone Health. Their study, “Assessing Mother-to-Child Transmission Risk in Asian American Women with Chronic Hepatitis B Receiving Prenatal Care at Two Community Health Sites in New York City, 2007-2017” was presented at the 2018 American Association for the Study of Liver Diseases Conference.