[Ovarian stimulation for in vitro fertilization using LHRH agonists: comparison of plasma and intra-follicular hormone profiles using "short" and "long" protocols].

Plasmatic estradiol (E2), progesterone (P) and LH were measured during the follicular phase of 343 cycles induced for in vitro fertilization (IVF) using a LHRH agonist in a "long protocol" (Group I) and 76 cycles in a "short protocol" (Group II). Moreover measurements in the plasma and follicular fluid (FF) of E2, P, LH, Delta-4-androstenedione (A), Testosterone (T) and prolactin (PRL) were performed on the day of oocyte retrieval (DO) in 46 women of the group I (111 FF) and 27 of the group II (67 FF). In the group I, plasma LH always remains below 3 mUl/ml, whatever the type of agonist (Buserelin or DTRP6-LHRH) and the type of stimulation (HMG or FSH) are used. On the other hand in the group II, mean plasma LH and P levels from D-5 to D-2 and those of FF LH, T and A on DO are significantly higher than in the group I. These changes are associated with a significant decrease of retrieved oocytes (5.8 versus 7.8 p less than 0.0001), pregnancy rate (15% versus 30%, p less than 0.01) and ongoing pregnancy rate (10% versus 22%, per oocyte retrieval, p less than 0.01). They suggest that the pituitary desensitization could be unsatisfactory with the short protocol use of agonist.