The CONSORT dosing algorithm individualizes recombinant human FSH (r-hFSH) doses for assisted reproduction technologies, assigning 37.5 IU increments according to patient characteristics: basal FSH, body mass index, age and antral follicle count. A prospective, uncontrolled, international, 18-centre, pilot study of normo-ovulatory women aged 18-34 years inclusive undergoing a long agonist treatment protocol was performed. Follitropin alfa filled-by-mass (GONAL-f (R)) dose was assigned by the algorithm and was intended to be altered only for risk of ovarian hyperstimulation syndrome (OHSS). Primary end-point was number of oocytes retrieved. Dose groups containing >= 5 patients were analysed: 75 IU (n = 49), 112.5 IU (n = 45), 150 IU (n = 34), 187.5 IU (n = 24), 225 IU (n = 10). Cancellations due to inadequate response were higher than expected in the 75 IU group (12/49). Overall, a median of 9.0 oocytes were retrieved (9.5, 9.0, 10.0, 12.0 and 8.0 in the 75, 112.5, 150, 197,5 and 225 IU groups respectively). Clinical pregnancy rates/cycle started were 31.3, 31.1, 35.3, 50.0 and 20.0%, respectively (overall, 34.2%). Two patients had severe OHSS. Use of the CONSORT algorithm achieved an adequate oocyte yield and good pregnancy rates in this preliminary study. Adjustment of the algorithm could reduce cancellation rates.