Hypogonadotropic hypogonadism is defined as a medical condition with low or undetectable
gonadotropin secretion, associated with a complete arrest of follicular growth and very low
estradiol. The main cause can be traced back to an irregular or absent hypothalamic
GnRH secretion, whereas only a minority suffers from a
pituitary disorder. The choice of treatment to reverse this situation is a pulsatile
GnRH application or a direct ovarian stimulation using
gonadotropin injections. The goal is to achieve a proper ovarian function in these cases for a short time to allow ovulation and chance of pregnancy. Since the pulsatile
GnRH treatment lost its former importance, several
gonadotropins are in use to stimulate follicular growth, such as urine-derived
human menopausal gonadotropin, highly purified
follicle stimulating hormone (FSH) or recombinant FSH, all with different success. The introduction of recombinant
luteinizing hormone (LH) and FSH provided an opportunity to investigate the distinct influences of LH and FSH alone and in combination on follicular growth in monofollicular ovulation induction cycles, and additionally on oocyte maturation, fertilization competence of the oocyte and embryo quality in downregulated IVF patients. Whereas FSH was known to be indispensable for normal follicular growth, the role of LH remained questionable. Downregulated IVF patients with this short-term
gonadotropin depletion displayed no advance in stimulation success with the use of recombinant LH. Patients with
hypogonadotropic hypogonadism undergoing monofollicular stimulation for ovulation induction showed clearly a specific role and need for both
hormones in normal follicular growth. Therefore, a combined stimulation with FSH and LH seems to be the best treatment choice. In the first half of the stimulation cycle the FSH dosage should exceed that of LH by 2:1, with an inverse ratio for the second half.