Hepatitis C infection among pregnant women in British Columbia: reported prevalence and critical appraisal of current prenatal screening methods.

BACKGROUND: Despite the fact that hepatitis C virus (HCV) is a relatively common infection in Canada, particularly in British Columbia (BC), there is a paucity of information on actual HCV prevalence in pregnant women. At present, pregnant women are only screened if they fit risk criteria, which may result in under-identification of HCV in this population. The purpose of this study was to determine the overall prevalence rate, age and geographic distribution of reported HCV infection among pregnant women in BC, and compare results to a previously conducted anonymous seroprevalence survey. METHODS: Reported HCV prevalence was determined through a confidential database linkage of all prenatal screening results at the Canadian Blood Services (CBS) with all HCV test results at the Provincial Laboratory, from May 2000 to Oct 2002. Data were stratified by age group and geographic location, and subsequently compared to an anonymous prenatal seroprevalence survey conducted in 1994. RESULTS: The overall HCV prevalence rate was 50.3/10,000 (95% CI 46.3-54.6), or 0.5% of the cohort. Prevalence was highest in the northern BC region (66.2/10,000, 95% CI 51.4-85.3) and lowest in the populous suburban region southwest of Vancouver (38.0/10,000, 95% CI 32.3-44.8). Of note, the rate of reported HCV among pregnant women was significantly lower than the anonymous seroprevalence rate: 50.3/10,000 vs. 91.3/10,000 (p < 0.0001). CONCLUSION: Rates of reported HCV among pregnant women were approximately 50% lower than the rates determined by the anonymous seroprevalence survey. Further research is needed to determine the relative merits of the current selective screening policy versus universal prenatal HCV screening in pregnancy.

Inadequacy of plasma acyclovir levels at delivery in patients with genital herpes receiving oral acyclovir suppressive therapy in late pregnancy.

OBJECTIVE: Acyclovir therapy in late pregnancy among women with recurrent genital herpes is effective in decreasing genital lesion frequency and subclinical viral shedding rates at delivery, thereby decreasing the need for Caesarean section. Despite good adherence and increased dosing schedules, breakthrough lesions and viral shedding are still observed in some women at or near delivery. Anecdotal evidence suggests that low levels of herpes simplex virus replication at delivery may result in transmission to the neonate. Therefore, defining optimal acyclovir dosing during labour and delivery is warranted. Our objectives were to determine actual maternal and fetal acyclovir levels at delivery, and explore associations between acyclovir levels, duration of labour, and time since last acyclovir dose. METHODS: Twenty-seven patients were prescribed oral acyclovir 400 mg three times daily from 36 weeks' gestation. Cord blood (venous and arterial) and maternal venous blood samples were collected at delivery, and acyclovir levels measured using capillary electrophoresis. Correlations between duration of labour, and time since last acyclovir dose with acyclovir blood levels were calculated. RESULTS: Acyclovir levels were below the published mean steady-state trough value (180 ng/mL) in 52% of venous cord samples, 55% of arterial cord samples, and 36% of maternal samples. There was a significant inverse correlation between the time since last dose and venous cord levels (rs19 = -0.57, P < 0.015), arterial cord levels (rs16 = -0.63, P < 0.01), and maternal acyclovir levels (r10 = -0.69, P < 0.03). CONCLUSION: Oral dosing of acyclovir in women in late pregnancy may result in insufficient levels at delivery to prevent viral shedding. Alternative approaches that incorporate acyclovir dosing through labour, either through oral or intravenous administration, should be evaluated to assess effects on viral shedding.