Hepatitis B and Pregnancy: An Underestimated Issue

Maureen M. Jonas

Disclosures

Liver International. 2009;29(s1):133-139. 

In This Article

Abstract

Hepatitis B infection during pregnancy presents a unique set of management issues. Aspects of care that must be considered include maternal and fetal effects of hepatitis B, effects of pregnancy itself on the course of hepatitis B infection and its complications, treatment of hepatitis B during pregnancy and prevention of perinatal infection. There are insufficient studies to date regarding these concerns; most are from the Far East, and many have important limitations, but some have yielded valuable data. Pregnant women with acute hepatitis B virus (HBV) infection typically have a course not very different from that in the general adult population, but the risk of transmission of HBV to neonates increases the later in gestation the acute infection occurs. Chronic HBV infection is usually mild in pregnant women, but may flare shortly after delivery. The risk of perinatal transmission is highest in women with high levels of viraemia; this may be a factor in the small but reproducible failure rate of current immunoprophylaxis strategies. Obstetrical policies must be assessed with respect to detection of maternal infection and liver disease, as well as with respect to perinatal transmission risk. In addition to the usual issues of drug efficacy and safety in the affected individuals, effects on the developing fetus must be considered. This paper reviews the current experience in each of these areas, and highlights the need for further investigation into this critical but often underestimated topic.

Introduction

Of the estimated 350 million individuals chronically infected with hepatitis B virus (HBV) worldwide, it is generally accepted that at least 50% acquired their infections either perinatally or in early childhood, especially in countries where HBV is endemic.[1] This is attributed to the high rates of HBeAg-positive infections in women of child-bearing age in these parts of the world, and the efficient transmission of infection from these women to their newborns. It has long been recognized that prevention of perinatal transmission is a high priority in the attempt to decrease the global burden of chronic HBV. Immunoprophylaxis with hepatitis B immune globulin (HBIG) and hepatitis B vaccine is known to be safe and effective, but applied variably in different geographical regions. Even with proper vaccination, 5–10% of infants of HBeAg-positive women become infected, and so there is opportunity for improvement in prevention strategies. In addition, the interaction of HBV infection and pregnancy itself is an area for further study.

The prevalence of chronic HBV infection in pregnant women in urban areas of the USA varies by race and ethnicity.[2] As expected, the highest rate (6%) is in Asian women. The rates in black, white and Hispanic women are 1, 0.6 and 0.14% respectively. Similar data are not available for European countries, but are expected to mirror those in the general populations of each nation, especially as determined by the numbers and countries of origin of immigrants.[3,4] In areas of high endemicity, such as China, other Far East countries and Africa, rates are proportionately higher. In the USA, testing for HBsAg is recommended for every pregnant woman, regardless of previous testing or vaccination.[5] Women who have not had this testing and those with risk factors for HBV acquisition should be tested at presentation for delivery. In Europe, there is no consistent policy with respect to testing of women for HBV infection during pregnancy, and many countries rely on historical 'risk factors' to determine indications for screening. However, a recent report from Denmark indicates that approximately 50% of infected pregnant women would not have been identified using this strategy,[6] a proportion that closely resembles that found in a comparable study in an urban US hospital a number of years ago.[7] In addition, changing immigration patterns in Europe indicate that HBV prevalence will vary greatly at a regional level within each country, and it has been suggested that there is a need to provide a more general immunization programme to protect the population at large.[8] The benefits of detection of infected pregnant women include not only identification of infants who require prophylaxis, but of women who might need treatment, and sexual and household contacts who will benefit from testing, counselling, vaccination or therapy if indicated.

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