Drugs used in in vitro fertilisation procedures.

The drugs used in in vitro fertilisation (IVF) procedures have the ability to stimulate the ovaries either directly or indirectly to cause multiple follicular development. In most centres today combinations of drugs in various regimens are used and a large number of oocytes are obtained for in vitro fertilisation. Despite that, the overall pregnancy rate is still low, and has improved little during the last 5 years. Possible effects of the drugs on the oocyte maturation process and the endocrinology of the menstrual cycle may contribute to the low success rate. The recent use of gonadotrophin releasing hormone (GnRH) analogues which block endogenous gonadotrophin secretion, in combination with controlled stimulation of the ovaries with exogenous gonadotrophins, tends to be more successful. However, more suitable protocols for better synchronisation of follicle development and a reduction in the cost of the drugs are required to make in vitro fertilisation a more readily available method for the treatment of infertility.