ADMINISTRATION OF PROGESTOGENS TO HASTEN PITUITARY DESENSITIZATION AFTER THE USE OF GONADOTROPIN-RELEASING-HORMONE AGONIST IN IN-VITRO FERTILIZATION - A PROSPECTIVE RANDOMIZED STUDY

Objective: To assess the effect of administration of adjuvant IM proge stogen to patients undergoing IVF who were not pituitary desensitized after 14 days of GnRH agonist (GnRH-a) administration. Design: Prospec tive randomized study. Setting: A tertiary referral center for assiste d conception. Patients: Forty-nine patients undergoing 51 IVF treatmen t cycles. Intervention: Patients in whom the endometrial thickness was >5 mm or who had an ovarian cyst >15 mm after 14 days of GnRH-a admin istration were recruited if the serum E(2) concentration was >27.24 pg /mL (>100 pmol/L). Patients in group 1 (n = 22) received a single IM i njection of 100 mg P whereas patients in group 2 (n = 29) did not. Pat ients in both groups continued to receive SC GnRH-a 500 mu g/d and had serum E(2) levels measured every 3 days until the concentrations were less than or equal to 100 pmol/L. Main Outcome Measures: The number o f days of GnRH-a administration from recruitment until serum Ea concen tration measured less than or equal to 100 pmol/L, number of cycles wi th withdrawal bleeding, number of days from recruitment to withdrawal bleeding, total dose of hMG used, number of follicles >14 mm, number o f oocytes, number of embryos, and pregnancy rates per cycle commenced and per ET. Results: There were no significant differences in all the above parameters except in the mean number of days from recruitment to onset of withdrawal bleeding, which were 5.33 +/- 0.7 (mean +/- SEM) and 8.62 +/- 1.26 days in groups 1 and 2, respectively The pregnancy r ate per ET was higher in group 1 (38.88%) when compared with group 2 ( 19.04%). However, this difference was not statistically significant. C onclusions: Adjuvant administration of a single IM injection of proges togen hastens the onset of withdrawal bleeding in patients who are not pituitary desensitized after 2 weeks of administration of SC GnRH-a. It does not appear to affect the length of time the serum E(2) concent rations take to reach basal levels or to alter the ovarian responsiven ess to exogenous gonadotropins.