59 - Individual Prediction of Mother-to-Child Transmission in Pregnant Individuals who Screened Positive for Hepatitis C Antibodies.

Objective: The CDC now recommends universal screening for hepatis C virus (HCV) antibodies in pregnancy, but reliable prediction of mother-to-child transmission (MTCT) to an individual fetus is not available. Our objective was to develop an internally validated prediction model for MTCT of HCV.

Study Design: Secondary analysis of a multicenter observational study of HCV in pregnancy. Participants were eligible for this analysis if they were HCV-antibody positive and had data available to determine MTCT status of HCV at or greater than 18 months of age. Potential factors that could be assessed prior to neonatal discharge were considered. A bootstrap resampling method was used to develop logit models for prediction. Backward elimination was performed for each of the 1000 bootstrap samples and candidate models were developed based on the frequency with which each candidate factor was selected in these models. The final predictor model was based on goodness of fit (Hosmer-Lemeshow test) and predictive ability (c-index).

Results: Of 772 individuals with HCV who were enrolled, 432 (56%) had data available to assess MTCT at > 18 months of age. The overall rate of MTCT was 6% (95%CI 4 – 9%). The final predictor model included 2 variables: a maternal HCV RNA titer > 10⁶ IU/mL (aOR 8.22, 95%CI 3.16 – 21.4) and any antepartum bleeding (aOR 3.26, 95%CI 1.32 – 8.03). The area under the ROC curve was 0.76 (95%CI 0.67 – 0.86), indicating moderate classification ability. For a child born to an individual with an HCV RNA titer > 10⁶ IU/mL and antepartum bleeding the probability of MTCT was 29% (95%CI 15 – 47%). In contrast, a patient with an HCV RNA < 10⁶ IU/mL and no antepartum bleeding had a probability of MTCT of 2% (95%CI 1 – 4%).


Conclusion: We developed a multivariable model to stratify patients according to individual risk of MTCT of HCV based on information available during pregnancy. Importantly, mode of delivery was not associated with MTCT. Now that universal screening in pregnancy is likely to identify more HCV positive patients, our results provide data to aid in counseling and inform future clinical trials.