Further improvement of IVF treatment may be facilitated by challenging current concepts of "success" in assisted reproduction. Defining success as term healthy live birth rate per time period in relation to cost, patient discomfort and risks of complications would reduce the present emphasis on single cycle outcome. Strategies involving single embryo transfer and milder ovarian stimulation protocols may allow for more IVF cycles in the same period of time, resulting in similar numbers of healthy term live births, despite a minor reduction in birth rate per treatment cycle. The present thesis addresses these novel approaches for defining and achieving success in IVF.