Follicle cysts after menstrual versus midluteal administration of gonadotropin-releasing hormone analog in in vitro fertilization

The incidence and behavior of follicle cysts after different timing of gonadotropin-releasing hormone analog (GnRH-a) administration was studied in 321 in vitro fertilization (IVF) cycles. Group M included 198cycles in which GnRH-a was injected at menstruation. Of these, 171 (88.6%) were without cysts (group M1) and 27 (13.6%) with cysts (group M2). Group L comprised of 123cycles in which GnRH-a was administered in the midluteal phase. Of them, 70 (56.9%) were without cystic finding (group L1), 19 (15.4%) with follicle cysts (group L2), and 34 cases (27.6%) with visible corpus luteum at the time of GnRH-a initiation (group L3). Both groups with follicle cysts demonstrated a higher luteinizing hormone peak and continuous elevated estradiol (E 2 ) levels. In group M2, the E 2 rise and the cysts persisted longer compared with group L2. Gonadotropin treatment was accordingly postponed until the cysts regressed spontaneously. Only two cases of group M2 required aspiration of the cysts. Follicle cyst formation is not related to the timing of GnRH-a administration and their occurrence did not have adverse effects on IVF outcome.