- Women who are pregnant, lactating, or planning to become pregnant during the study period, or women of childbearing potential who are not using acceptable contraceptive methods. A woman is considered of childbearing potential if she is not surgically sterile or is less than 1 year since last menstrual period. Examples of acceptable contraceptive methods include abstinence, intrauterine device (IUD) or double barrier method, oral or injectable contraceptives.