- Patients must not be pregnant or nursing, and all patients (both men and women) must be willing to practice birth control for 1 month prior, during and for 4 months after treatment with thalidomide. It has been proposed that thalidomide may interfere with hormonal-based contraception, therefore, barrier methods of contraception (i.e. diaphragm, condom) MUST be used rather than, or in addition to birth control pills.