PULSATILE SUBCUTANEOUS VERSUS BOLUS INTRAMUSCULAR GONADOTROPIN ADMINISTRATION AFTER PITUITARY SUPPRESSION WITH A LONG-ACTING GONADOTROPIN-RELEASING-HORMONE ANALOG - A CONTROLLED PROSPECTIVE-STUDY

The potential advantages of pulsatile s.c. administration instead of d aily bolus i.m. administration of human urinary gonadotrophin preparat ions were tested after the administration of a long-acting gonadotroph in-releasing hormone (GnRH) analogue within a programme for in-vitro f ertilization (IVF) and embryo transfer. First, the pharmacokinetic pro perties of human urinary gonadotrophins were analysed with immunologic al and biological methods, both during bolus i.m. injections and durin g pulsatile s.c. administration. Second, a prospective randomized cont rolled study was performed in 75 patients undergoing IVF/embryo transf er in whom the effects of pulsatile s.c. administration were compared with the effects of single daily bolus i.m. injections of the same gon adotrophin preparation. The results showed that neither method of gona dotrophin administration induced measurable changes in the serum conce ntration of luteinizing hormone (LH). Both oestradiol and androstenedi one concentrations were slightly lower during pulsatile s.c. gonadotro phin administration, suggesting that this method of gonadotrophin admi nistration results in less LH occupying the ovarian LH receptors. Puls atile s.c. gonadotrophin administration resembles a continuous infusio n of follicle-stimulating hormone (FSH). Significant fluctuations in t he serum concentrations of FSH were observed during single daily bolus i.m. administration of human urinary gonadotrophins, but the pregnanc y rate of IVF/embryo transfer per cycle after pulsatile s.c. administr ation was not significantly better than after the daily bolus i.m. inj ection of gonadotrophins (42.1 versus 37.2%). It is concluded that pul satile s.c. administration of gonadotrophins instead of single daily i njections does not improve the pregnancy rate in IVF/embryo transfer.