FOLLICULOGENESIS - THE STIMULATED WAY

The initial techniques of stimulating follicular development in the an ovulatory woman involved the use of human pituitary gonadotrophin (hPG ) and thus replaced the function of the pituitary gland. Despite extre me care with administration of hPG and extensive monitoring to assess the ovarian response, ovarian hyperstimulation and multiple pregnancy were common. Less expensive and easier methods of treatment soon follo wed with oral clomiphene citrate (early 1960s), oral bromocriptine (ea rly 1970s) and pulsatile gonadotrophin-releasing hormone (late 1970s) being used. Currently all of these methods, alone or in combination, a re employed and successful ovulation induction (except in women with e levated FSH levels) can now virtually be guaranteed. Controlled ovaria n hyperstimulation, just the outcome one was attempting to avoid in th e treatment of anovulatory women, has become the treatment of choice f or women having in vitro fertilization (IVF) or gamete intrafallopian transfer (GIFT). The extra oocytes produced by this treatment results in more embryos being available for transfer and/or freezing and impro ves the overall pregnancy rate. The concurrent use of gonadotrophin-re leasing hormone agonists (GnRH-a) has resulted in more mature oocytes being developed, less cancelled cycles for a spontaneous midcycle LH s urge, and allowed even more embryos to be produced thereby increasing the pregnancy rate further to the current expected 20% per cycle comme nced. As techniques are further modified, adverse effects of elevated LH levels on pregnancy and take home baby rates should be able to be o vercome, and oocyte freezing and long-term storage should become a pos sibility.The latest advance in treatment has been the production of pu re FSH by a recombinant technique, thereby allowing anovulatory or ovu latory women to be given the pure hormone rather than one contaminated with significant amounts of LH. Normal follicular development, as ass essed ultrasonically, has been observed during such treatment cycles d espite the fact the oestradiol levels are low.