- Females are either postmenopausal for at least 1 year, are surgically sterile for at least 3 months, or must agree to take appropriate precautions to avoid pregnancy (with at least 99% certainty) from screening through 12 months after the last dose of rituximab if of childbearing potential. (Note: Permitted methods that are at least 99% effective in preventing pregnancy should be communicated to the participants and their understanding confirmed).