The toxicity of cancer chemotherapy agents often leaves women of childbearing age permanently infertile. A new hormone-blocking procedure, in which a patient's reproductive system is placed into a type of temporary "prepubescent stasis," enables women to have children after chemotherapy ends. "Our research stems from the observation that pre-pubescent girls who undergo chemotherapy fare much better in terms of preserving their fertility than 25- or 35-year-old women," explains Dr. Zeev Blumenfeld, a researcher of reproductive endocrinology at the Technion-Israel Institute of Technology who headed the study. Dr. Blumenfeld and his colleagues discovered that they could simulate the "pre-pubertal hormonal milieu" and protect the ovarian function of young women by administering a natural hormone called gonadotropin-releasing hormone analogue [GnRH-a]. The agent is given to patients beginning two weeks before they start chemotherapy and for about 4 to 6 months or until completion of chemotherapy. "Our results suggests the beneficial effect of GnRH-a co-treatment may be extrapolated toward the preservation of future fertility and ovarian function in every young woman in the reproductive age exposed to chemotherapy agents," says Dr. Blumenfeld.