Although data on approximately 300 prospectively followed pregnancies with paternal exposure to ribavirin have not shown an increased risk of malformation compared to the general population, nor any specific pattern of malformation, male patients and their female partners of childbearing age must be counseled to each use an effective contraceptive during treatment with Ribavirin and for seven months after treatment Men whose partners are pregnant must be instructed to use a condom to minimise delivery of ribavirin to the partner.