Roles of follicle stimulating hormone and luteinizing hormone in controlled ovarian hyperstimulation.

With the advent of recombinant follicle stimulating hormone (FSH) and luteinizing hormone (LH), free from contamination with each other (Loumaye et al., 1995), it is possible to dissect the individual contributions of FSH and LH to the regulation of ovarian function and to define optimal gonadotrophin usage in controlled ovarian hyperstimulation (COH) (Hillier, 1994). Basic and clinical research evidence is accumulating to propose that the future use of these new pharmaceuticals will allow systematic improvements in the treatment regimes used to achieve COH (Hillier et al., 1995). Here, I briefly re-examine some of the physiological principles that need to be borne in mind as these developments take place.