Female sex is a protective factor for the progression of fibrosis in patients with chronic hepatitis C virus (HCV) infection. Experimental data suggest that estrogens may have an antifibrotic effect. The objective of this study was to evaluate the influence of past pregnancies, oral contraceptives, menopause, and hormone replacement therapy (HRT) on liver fibrosis progression in HCV-infected women. Four hundred seventy-two HCV-infected women received a survey regarding prior pregnancies, menopause, and the use of oral contraceptives and HRT. The impact of these variables on liver fibrosis and its progression were evaluated using multivariate analyses considering all putative confounding factors. Two hundred one women completed the survey (43% response rate), 157 of whom had an estimated date of HCV infection (96 postmenopausal women, 96 women with previous pregnancies, and 105 women with past use of oral contraceptives). Through multivariate analyses, the estimated rate of fibrosis progression was higher in postmenopausal (P < .05) and nulliparous (P = .02) women and was associated with greater histological activity (P < .001). Prior use of oral contraceptives had no significant influence. Among postmenopausal women, the estimated rate of fibrosis progression (±SE) was lower in women who received HRT compared with untreated patients (0.099 ± 0.016 vs. 0.133 ± 0.006 METAVIR units/yr; P = .02) and was similar to that of premenopausal women (0.093 ± 0.012 METAVIR units/yr; P value not significant). In conclusion, menopause appears to be associated with accelerated liver fibrosis progression in HCV-infected women, an effect that may be prevented by HRT. Pregnancies may have a beneficial impact on the long-term progression of liver fibrosis. (HEPATOLOGY 2004;40:1426–1433.)