Gonadotropin Stimulation Regimens and Oocyte Embryo Quality

In the normal human menstrual cycle, the final phase of ovarian folliculogenesis leading upto the pre-ovulatory stage is gonadotropin dependent. Luteinising hormone (LH) acts synergistically with follicle stimulating hormone (FSH) to achieve follicular steroidogenesis, luteinisation and ovulation. It therefore follows that the maturational process of the oocyte contained within the follicle and its subsequent development can be influenced by the levels of LH and FSH in the circulation. With the recent availability and increasing use of FSH-only preparations the question of possible effects on oocyte development needs to be reviewed. This paper looks at the available evidence comparing FSH-only preparations to that of combined FSH and LH regimens in both the hypogonadotropic hypogonadal model as well as normogonadotropic women undergoing in vitro fertilisation (IVF).