Reducing Risk for Mother-to-Infant Transmission of Hepatitis C Virus: A Systematic Review for the U.S. Preventive Services Task Force

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Reducing Risk for Mother-to-Infant Transmission of Hepatitis C Virus: A Systematic Review for the U.S. Preventive Services Task Force

Erika Barth Cottrell, PhD, MPP; Roger Chou, MD; Ngoc Wasson, MPH; Basmah Rahman, MPH; and Jeanne-Marie Guise, MD, MPH

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Abstract
Background: Mother-to-infant transmission is the leading cause of childhood hepatitis C virus (HCV) infection, with up to 4000 new cases each year in the United States.

Purpose: To evaluate effects of mode of delivery, labor management strategies, and breastfeeding practices on risk for mother-to-infant transmission of HCV.

Data Sources: MEDLINE (1947 to May 2012), the Cochrane Library Database, clinical trial registries, and reference lists.

Study Selection: Randomized trials and observational studies on mode of delivery, labor management strategies, and breastfeeding practices and risk for mother-to-infant transmission of HCV.

Data Extraction: Investigators abstracted and reviewed study details and quality using predefined criteria.

Data Synthesis: Eighteen observational studies evaluated the association between mode of delivery, labor management strategies, or breastfeeding practices and risk for mother-to-infant HCV transmission. Fourteen studies (2 good-quality, 4 fair-quality, and 8 poor-quality studies) found no clear association between mode of delivery (vaginal versus cesarean delivery) and risk for transmission. Two studies (1 good-quality and 1 poor-quality study) reported an association between prolonged duration of ruptured membranes and increased risk for transmission. Fourteen studies (2 good-quality, 2 fair-quality, and 10 poor-quality studies) found no association between breastfeeding and risk for transmission.

Limitations: Only English-language articles were included. Studies were observational, and most had important methodological shortcomings, including failure to adjust for potential confounders and small sample sizes.

Conclusion: No intervention has been clearly demonstrated to reduce the risk for mother-to-infant HCV transmission. Avoidance of breastfeeding does not seem to be indicated for reducing transmission risk.

Primary Funding Source: Agency for Healthcare Research and Quality.

An estimated 40 000 children are born to hepatitis C virus (HCV)–positive women each year (1). Mother-to-infant (vertical) transmission is the main route of childhood HCV infection (2). Estimates for the rate of vertical transmission range from 3% to 10% (2 - 5). Risk for transmission is highest among women with a high viral load at delivery (2 - 6) and those co-infected with HIV (5,7). Although antiviral therapies are contraindicated in pregnancy because of teratogenic risks, prenatal HCV screening to identify HCV-infected women unaware of their status might lead to other interventions during labor and delivery or in the perinatal period that reduce risk for mother-to-infant transmission (8).

The purpose of this review was to synthesize the evidence on the effects of mode of delivery, labor management strategies, and breastfeeding practices on risk for mother-to-infant transmission. This review was performed as part of a larger report on HCV screening (9) and will be used by the U.S. Preventive Services Task Force (USPSTF) to inform its prenatal HCV screening recommendations.

Discussion Only

Full Text Available @ Annals Of Internal Medicine

Vertical transmission is the leading cause of childhood HCV infection, and identification of effective management strategies to reduce risk for transmission is an important clinical and public health concern. However, the primary finding of this review as summarized in the Table is that no perinatal management strategy has clearly been shown to reduce risk for HCV transmission. Observational studies consistently found no evidence of an association between breastfeeding and risk for vertical transmission, consistent with data suggesting that transmission typically occurs in utero (23,33). Evidence on the effects of labor management strategies and mode of delivery on risk for transmission was somewhat conflicting. Two studies (5,24) reported increased risk for HCV transmission with more prolonged duration of ruptured membranes, similar to findings for other infectious agents transmitted vertically (such as group B streptococcus and HIV). However, other studies did not find vaginal delivery associated with increased risk for vertical transmission versus cesarean delivery, and the largest single study (15) reported a non–statistically significant trend toward decreased risk, even though vaginal delivery is associated with longer duration of ruptured membranes. Possible explanations for the failure to find an association between vaginal delivery and increased risk for transmission could include threshold or modifying effects related to the duration of rupture, viral load, or other factors. Cohort studies that focus on women with longer rupture of membranes or high viral load and perform statistical adjustment on other potential confounding factors could help clarify the effects of mode of delivery on transmission risk. Randomized trials are less susceptible to confounding but would involve potential challenges related to the acceptability of randomly assigning HCV-infected women to elective cesarean delivery versus planned vaginal birth....

Full Text Available @ Annals Of Internal Medicine