PRESERVED PITUITARY-RESPONSE UNDER OVARIAN STIMULATION WITH HMG AND GNRH ANTAGONISTS (CETRORELIX) IN WOMEN WITH TUBAL INFERTILITY

Objective: To examine the pituitary response in patients undergoing sh ort-term application of the GnRH antagonist Cetrorelix in the mid-cycl e phase for hypophysial suppression of premature LH surges within an I VF-program. Design: Twenty patients suffering from primary or secondar y tubal infertility were stimulated with hMG from cycle day 2. From da y 7 till ovulation induction Cetrorelix was administered in two differ ent dose regimens (15 patients 3 mg s.c. daily; 5 patients 1 mg s.c. d aily). Three hours before ovulation induction a GnRH test was performe d using 25 mu g of native GnRH and the pituitary response examined by measurement of the serum LH concentration after 30 min. Results: Prema ture LH surges could be avoided in the 3-mg group and in the l-mg grou p, respectively. Due to this, none of the cycles had to be cancelled. Oestradiol profiles and ultrasound demonstrated a satisfactory follicu lar maturation. All patients showed pronounced suppression of the seru m LH levels before ovulation induction. The mean increase of serum LH due to the performed GnRH test was 10 mlU/ml for the 3-mg group, while the average maximum in the 1-mg group was about 32.5 mlU/ml. Conclusi ons: The pituitary response is preserved by the treatment with the GnR H antagonist Cetrorelix. The extent of suppression of the adenohypophy sis, as expressed by the different reactions on GnRH test, can be modu lated by the dosage administered. This should allow ovulation inductio n by GnRH or one of its agonists instead of hCG, which could be benefi cial in patients at high risk of Ovarian Hyperstimulation Syndrome (OH SS) and those suffering from Polycystic Ovary Disease (PCOD).