 - Pregnancy or breastfeeding. Pregnancy in fertile women is excluded by a measurement of HCG in a blood sample. Sterile or infertile women are excluded from the requirement to use anticonception. To be considered sterile or infertile, the patient must have undergone surgical sterilization vasectomybilateral tubectomy, hysterectomy and bilateral ovariectomy or be post-menopausal defined as the absence of menstruation. 