Mild IVF stimulation

For many years, assisted conception technologies were characterized by a limited efficiency that was in some was compensated for by aggressive ovarian stimulation aimed at obtaining large number of oocytes. However, this approach placed a considerable burden of cost, side effects, and risk of complications on the patient. Recognition of this, and of the potentially detrimental effects of gamete and endometrial exposure to supra-physiological levels of gonadotrophins and estrogens, and concern as to the viability of the oocytes thus obtained led to the development of milder stimulation protocols, and increased use of natural cycle IVF. In this article, the principles behind mild stimulation and natural cycle IVF are outlined, and the published data relating to their respective efficacy, advantages, and disadvantages are reviewed.