Natural cycles in IVF have been used for patients who have shown a poor response in at least two previous attempts with gonadotropin stimulation 171
how long for propecia to work The significant cardiovascular side effects of tamoxifen, coupled with lack of a survival benefit, potential for genotoxicity, and failure to provide a significant risk reduction for estrogen receptor negative breast cancer, all contribute to the low acceptance of tamoxifen chemoprevention in premenopausal women at high risk for breast cancer