Mild vs conventional ovarian stimulation in intrauterine insemination. a prospective randomized study

Abstract

Our aim was evaluate a mild ovarian stimulation protocol starting the gonadotropin administration after natural follicular recruitment and compared with conventional ovarian stimulation as ovulation induction to intrauterine insemination. A prospective randomized study of two different protocols of ovarian stimulation. Patients with less than three attempts of IUI, younger than 41 years old, with body mass index lower than 35 Kg/m2 and regular menstrual cycles were randomized to start 75 IU per day of HP-HMG (Menopur, Ferring, Spain) from the day 2 of menstrual period (conventional stimulation: CS) or after the leader follicle reaches 11 mm of mean diameter (mild stimulation: MS). A single intrauterine insemination was performed 36 hours after hCG administration. Ethical committee of our institution approved the present study. From January 2008 to February 2011, 39 patients underwent to 54 cycles of IUI were included. No differences were found between patients of CS compared with MS in age (34.3 ± 3 vs 34.5 ± 2.6 years), levels of estradiol, FSH and progesterone on days 0 or 6 of ovarian stimulation. The number of follicles with mean diameter between 15 to 17 mm on hCG day was similar (CS: 1.8 ± 3 follicles, MS: 1.1 ± 0.3 follicles) and also similar number of follicles of 18 mm or more diameter were found in both groups (p: 0.158). Similar male factor was documented between groups.Significant differences were found in estradiol level on day 4 of stimulation (113.4 ± 53 vs 63.8 ± 55.5 pg/mL), days of stimulation (9.83 ± 2.5 vs 5.94 ± 2.1) and amount of gonadotropins (635.37 ± 263.1 vs 396.3 ± 191) between CS compared with MS group (P< 0,05). No difference was found in pregnancy rate per cycle in CS group (12,5%) compared with MS group (22.2%) (p:0.473). Mild stimulation protocol needs fewer amounts of gonadotropins, fewer days of ovarian stimulation and it reaches similar pregnancy rate than conventional ovarian stimulation in intrauterine insemination.