In most cases, having viral hepatitis during pregnancy does not increase the risk of miscarriage or pregnancy loss -- although it can cause other complications, some potentially serious in the long-term.
Several studies have looked at what happens when women infected with hepatitis during pregnancy. For most types of acute viral hepatitis infections (meaning that the mom gets hepatitis for the first time during the pregnancy), the infection tends to run its course without posing serious risks to the mother's life or the baby, although acute infection in the third trimester can mean an increased risk of preterm labor. The exception is hepatitis E, which has a high mortality rate for both the mother and the developing baby. (Hepatitis E is rare in the United States.)
Even though it probably doesn't cause miscarriage, that's not to say that viral hepatitis during pregnancy is any small matter of concern. In hepatitis B and hepatitis C, moms can be at risk of developing chronic infection or of passing the virus along to their babies. In hepatitis C, the virus gets passed on to the baby in only about 4% of cases, but hepatitis B can have as much as a 90% chance of being passed to the baby when the mom gets sick in the third trimester -- and most infected babies develop chronic infections.
Babies born to mothers with hepatitis B should receive immune globulin and hepatitis B vaccination at birth in order to minimize the risks of chronic infection. There is no vaccine against hepatitis C but doctors can take precautions during delivery to minimize the risks to the baby when the mother has hepatitis C.
As for other forms of hepatitis, hepatitis D is only able to infect individuals who already carry hepatitis B, so taking precautions to protect a baby against hepatitis B will also protect against hepatitis D. Hepatitis E and A do not lead to chronic infections. Hepatitis E lacks a vaccine, but a vaccine is available against hepatitis A.
If you think you have symptoms of hepatitis or if you feel you are at risk for infection, speak to your doctor immediately about testing and treatment (if needed).
Sources
American College of Obstetricians and Gynecologists, "Hepatitis B Virus in Pregnancy." ACOG Education Pamphlet AP093 Apr 2008. Accessed 12 Sept 2008.
Elinav, E., I. Ben-Dov, Y. Shapira, N. Daudi, R. Adler, D. Shouval, and Z. Ackerman, "Acute Hepatitis A Infection in Pregnancy Is Associated With High Rates of Gestational Complications and Preterm Labor." Gastroenterology Apr 2006. Accessed 12 Sept 2008.
Hunt, Christine M. and Ala I. Sharara, "Liver Disease in Pregnancy." American Family Physician 1999. Accessed 11 Sept 2008.
Jabeen, T., B. Cannon, J. Hogan, M. Crowley, C. Devereux, L. Fanning, E. Kenny-Walsh, F. Shanahan and M.J. Whelton, "Pregnancy and pregnancy outcome in hepatitis C type 1b." QJM 2000. Accessed 11 Sept 2008.
Sookoian, Silvia, "Effect of pregnancy on pre-existing liver disease: Chronic viral hepatitis." Annals of Hepatology 2006. Accessed 11 Sept 2008.
Tse, Ka Yu, Lai Fong Ho, and Terence Lao, "The impact of maternal HBsAg carrier status on pregnancy outcomes: A case-control study." Journal of Hepatology Nov 2005. Accessed 12 Sept 2008.
