Pregnancy after administration of high dose recombinant human LH alone to support final stages of follicular maturation in a woman with long-standing hypogonadotrophic hypogonadism.

Traditionally, the roles of LH in folliculogenesis have been considered to be limited to stimulating theca cells androgen production, triggering ovulation and supporting the corpus luteum. However, in the late stages of follicle development, granulosa cells become receptive to LH stimulation and LH becomes capable of exerting its actions on both theca cells and granulosa cells. Thus, it has been postulated that once an appropriate (i.e. LH-responsive) stage of follicular development has been achieved in response to treatment with FSH, there are theoretical grounds for reducing or completely withdrawing FSH and maintaining tonic stimulation of the dominant follicle with exogenous LH. This hypothesis was tested in a woman with long-standing hypogonadotrophic hypogonadism, which is the best and only true model to investigate correctly any LH hypothesis. Ovulation induction treatment was carried out with daily s.c. injections of 150 IU recombinant human FSH (rhFSH) (increased to 225 IU daily on stimulation day 15) and 375 IU recombinant human LH (rhLH). When a 14-mm follicle was identified on stimulation day 26, rhFSH was discontinued and from treatment days 26 to 29 the patient was given only rhLH at the above-mentioned dose of 375 IU/day. On treatment day 30, the single dominant follicle measured 22 mm in diameter and oestradiol serum concentration was 148 pg/ml. Thus, an injection of 10,000 IU i.m. human chorionic gonadotrophin was given and sexual intercourse was advised. The patient conceived and a viable singleton intrauterine pregnancy was obtained.