ABSTRACT
The first successful birth after in υitro fertilization (IVF) was achieved in a natural, unstimulated cycle.1 However, by the beginning of the 1980’s it became apparent that multiple follicular stimulation was an important tool for better outcome results after IVF: pregnancy rates improved with the use of ovulationinduction techniques, mainly as a result of transferring severalembryos.2-4
Urinary extracts of gonadotrophins from postmenopausal women were available for use in the human since the 1960’s5-6 at either FSH: LH ratio of 1:1 (prepared as human menopausal gonadotrophin; HMG) or later in the preparation of FSH HP (high purity) with only traces of LH (<0.1 IU LH/1000 IU FSH). During the 1990s, recombinant DNAtechnology permitted the introduction of rFSH, a preparation totally devoid of LH activity.
