[20 years in vitro fertilization: what follows?].

During the last two decades in-vitro fertilization (IVF) developed on a worldwide scale by increasing numbers of treated couples and by extending the medical indications. Existing treatment protocols have been optimized to such an extent that pregnancy rates over 30% are reached in many treatment units. Further improvements of the pregnancy rate may be achieved with assisted hatching, which is now the subject of a large European multicentric prospective study based on the University of Lausanne. On the other hand, the occurrence of multiple pregnancies, which is the main complication of IVF, may be limited by reducing the number of embryos replaced. Further improvements of treatment efficacy may result from the introduction of new medications, such as recombinant FSH or GnRH-antagonists, allowing for the adaptation of the treatment protocol used to the individual needs of each patient. A treatment protocol combining a GnRH-antagonist and gonadotropins may be particularly valuable in young patients for the purpose of avoiding the ovarian hyperstimulation syndrome. The major disadvantage of these novel medications consists of their increased costs. Therefore, a new treatment strategy is currently developed aiming at shortening the ovarian stimulation in combination of a prolongation of the laboratory phase. The in-vitro maturation of immature oocytes aspirated from small follicles previously primed with recombinant FSH has been shown to be a feasible alternative to the present treatment modalities. Cryopreservation of unfertilized oocytes together with in-vitro maturation may prove to be helpful for women prior to chemotherapy or radiation because of malignant diseases or for patients suffering from incipient ovarian failure. At present, there seems to be no alternative to assisted reproduction although the dominance of this technique may impede the development of more cause-related treatment strategies in infertility.