Mother to Child Transmission of Hepatitis
C Virus: A Case-Control Study of Risk Factors
Authors of the study: Sophie Poiraud, Hosp Tenon, Paris France; Joseph Cohen, Hosp Bicetre, Kremlin-Bicetre France; Xavier Amiot, Nadia Berkane, Antoine Flahault, Hosp Tenon, Paris France; Elisabeth Dussaix, Hosp Paul-Brousse, Villejuif France; Pauline Jouet, Hosp Tenon, Paris France; Olivier Bernard, Hosp Bicetre, Kremlin-Bicetre France; Jean-Didier Grange, Hosp Tenon, Paris France
Background: Mother-to-child transmission rate of hepatitis C virus (HCV) is low, less than 10 % in women not co-infected with HIV. Because most of published studies have included a small number of HCV-RNA positive children (N < 10), the transmission risk factors remain unclear. Invasive procedures, such as amniocentesis or use of forceps, could increase the risk of transmission.
The aim of the study was to evaluate the risk factors for vertical transmission of HCV, using a case-control design. Patients and methods: all children born to HCV-RNA positive, anti-HIV negative mothers were included in the study (patient group). Incident cases were HCV-RNA positive children after one month of age. Controls were HCV-RNA negative after 1 month of age and/or anti-HCV negative children.
The following risk factorswere analyzed : amniocentesis, vaginal or caesarean-section delivery, use of forceps, episiotomy, maternal breast-feeding or bottle-feeding.
Results: from January, 1992, to August, 2000, 161 mother-child pairs (51 cases and 110 controls) were included. The mean mother age was 31.2±5.9 years in the patient group compared with 32.6±5.2 years in the control group (NS).
Caesarean-section delivery rate was 13 % in the patient group and 22.9 % in the control group (p = 0.27). Vaginal delivery rate with forceps was 39.5 % in the patient group and 25 % in the control group (p = 0.13). Episiotomy rate was 61 % in the patient group and 57.9 % in the control group (p = 0.83). Amniocentesis rate was 16.6 % in the patient group and 25.3 % in the control group (p=0.27). Breastfeeding rate was 56.2 % in the patient group and 43.4 % in the control group (p = 0.16). Logistic regression analysis showed that vaginal delivery with forceps was the only significant and independent factor associated with vertical transmission (OR = 3.24, 95% CI [1.03;10.10], p=0.04).
We performed a secondary analysis for all variables limited to the 123 children of different mothers. The estimation of the OR related to the way of delivery was very close in this secondary analysis.
Conclusions: our study demonstrates an increased HCV vertical transmission risk during vaginal delivery with use of forceps compared with caesarean-section delivery. Episiotomy does not appear as a risk factor during vaginal delivery. Maternal breast-feeding was not found to be a risk factor (nevertheless, we cannot exclude a risk with a ratio lower than 3). Furthermore, amniocentesis does not increase the risk of mother-to-child transmission of HCV.
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