Hepatitis C
Hepatitis C is caused by an RNA virus that has 6 genotypes. The most common genotype is HCV1, which affects 79% of patients; approximately 13% of patients have HCV2, and 6% have HCV3.9 Of note, the 3 individuals who discovered this virus—Drs. Harvey Alter, Michael Houghton, and Charles Rice—received the 2020 Nobel Prize in Medicine.10
Hepatitis C is transmitted via sexual contact, parenterally, and perinatally. In many patient populations in the United States, hepatitis C is now more prevalent than hepatitis B. Only about half of all infected persons are aware of their infection. If patients go untreated, approximately 15% to 30% eventually develop cirrhosis. Of these individuals, 1% to 3% develop hepatocellular cancer. Chronic hepatitis C is now the most common indication for liver transplantation in the United States.1,9
In the initial stages of infection, hepatitis C usually is asymptomatic. The best screening test is detection of hepatitis C antibody. Because of the increasing prevalence of this disease, the seriousness of the infection, and the recent availability of remarkably effective treatment, routine screening, rather than screening on the basis of risk factors, for hepatitis C in pregnancy is now indicated.11,12
The best tests for confirmation of infection are detection of antibody by enzyme immunoassay and recombinant immuno-blot assay and detection of viral RNA in serum by PCR. Seroconversion may not occur for up to 16 weeks after infection. Therefore, in at-risk patients who initially test negative, retesting is advisable. Patients with positive test results should have tests to identify the specific genotype, determine the viral load, and assess liver function.1
In patients who have undetectable viral loads and who do not have coexisting HIV infection, the risk of perinatal transmission of hepatitis C is less than 5%. If HIV infection is present, the risk of perinatal transmission approaches 20%.1,13,14
If the patient is coinfected with HIV, a scheduled cesarean delivery should be performed at 38 weeks’ gestation.1 If the viral load is undetectable, vaginal delivery is appropriate. If the viral load is high, however (arbitrarily defined as >2.5 millioncopies/mL), the optimal method of delivery is controversial. Several small, nonrandomized noncontrolled cohort studies support elective cesarean delivery in such patients.14
There is no contraindication to breastfeeding in women with hepatitis C unless they are coinfected with HIV. In such a circumstance, formula feeding should be chosen. After delivery, patients with hepatitis C should be referred to a gastroenterology specialist to receive antiviral treatment. Multiple new single-agent and combination regimens have produced cures in more than 90% of patients. These regimens usually require 8 to 12 weeks of treatment, and they are very expensive. They have not been widely tested in pregnant women.1
Hepatitis D
Hepatitis D, or delta hepatitis, is caused by an RNA virus. This virus is unique because it is incapable of independent replication. It must be present in association with hepatitis B to replicate and cause clinical infection. Therefore, the epidemiology of hepatitis D closely mirrors that of hepatitis B.1,2
Patients with hepatitis D typically present in one of two ways. Some individuals are acutely infected with hepatitis D at the same time that they acquire hepatitis B (coinfection). The natural history of this infection usually is spontaneous resolution without sequelae. Other patients have chronic hepatitis D superimposed on chronic hepatitis B (superinfection). Unfortunately, patients with the latter condition are at a notably increased risk for developing severe persistent liver disease.1,2
The diagnosis of hepatitis D may be confirmed by identifying the delta antigen in serum or in liver tissue obtained by biopsy or by identifying IgM- and IgG-specific antibodies in serum. In conjunction with hepatitis B, the delta virus can cause a chronic carrier state. Perinatal transmission is possible but uncommon. Of greatest importance, the immunoprophylaxis described for hepatitis B is almost perfectly protective against perinatal transmission of hepatitis D.1,2
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