This chapter explores the concerns with conventional ovarian stimulation regimens, which have provoked a need to develop alternative strategies. Natural and modified natural cycles for in vitro fertilization (IVF) are briefly discussed. Elective single embryo transfer correlates well with the NHS funding policy. However, as long as couples pay for IVF treatments themselves, many of them will opt for double embryo transfer because it can result in a higher chance of success in older women. Clomiphene citrate (CC) acts antagonistically on the estradiol receptor at the hypothalamic level, inhibiting negative as well as positive feedback, and resulting in ovarian stimulation and suppression of the luteinizing hormone (LH) surge. To improve effectiveness, natural cycle IVF could be offered as a series of treatment cycles, since it is safer and less stressful compared with conventional stimulation. Mild ovarian stimulation aims at reducing the psychological burden of IVF treatment.