LH supplementation in mild stimulations cycles without pituitary suppression: a retrospective analysis

A cohort of patients addressed to a mild stimulation protocol was retrospectively analysed aiming at evaluating the effect of a luteinizing hormone (LH) activity containing stimulation compared to a pure follicle-stimulating hormone (FSH) drive in absence of any pituitary suppression. Due to a referral bias, the two groups (human FSH (hFSH) n = 210; hMG n = 105) were imbalanced for age with the hFSH group (mean age 38.4) being significantly older than the hMG group (mean age 36.8). But the clinical pregnancy rates (20%) did not differ between the groups. Secondary outcome variables showed a higher number of oocytes retrieved (3.02 vs. 2.31) and higher estradiol levels (1148 vs. 820) in the hMG/younger group whereas the fertilization rate (FR) was higher (54.8 vs. 63.8) in the FSH older/group. In spite of the LH content in the hMG product (~10 IU per vial), the LH concentration on the day of human chorionic gonadotropin (hCG) was higher, although non-significantly, in the hFSH group. We suppose hCG contained in hMG inhibited to some extent the natural release of LH from the non-suppressed pituitary. Concluding, the mild stimulation clinical pregnancy rates are satisfactory independently of the treatment choice. The hMG group showed a trend for a lower efficacy. This phenomenon might be limited to non suppressed cycles, but should be taken in due account also when designing full dose controlled ovarian hyperstimulation (COH) treatments.