- The effects of Alendronate on the developing fetus are unknown. For this reason, heterosexual women must agree to use TWO effective forms of birth control for the duration of study participation and for 8 weeks following the last dose of study medication. Women must combine a hormonal birth control method (e.g. combined oral contraceptive pill, vaginal ring, skin patch, injection, or copper IUD) in continuous use for >90 days prior to study entry (except in the case of a copper IUD), with a non-hormonal birth control method (e.g. diaphragm, cervical cap, cervical shield with spermicide, contraceptive sponge, or condom (male or female) with spermicide).