OBJECTIVE:

To determine the clinical pregnancy rate in the first cycle of intrauterine insemination with gonadotropin stimulation in relation to number of mature follicles and age and the use of GnRH antagonist on its development.

MATERIALS AND METHODS:

Analytic, retrospective study, we evaluated the first IUI cycle in 171 women stimulated with different protocols of ovarian stimulation in a period of two years. The patients were divided into two groups: <35 and ≥35 years old and the use of GnRH antagonist.

RESULTS:

60.4 and 65.1% of patients <35 and ≥35 years old respectively, developed 2 to 4 mature follicles; the clinical pregnancy rate <35 and ≥35 years old was 27.7 y 28.5% and 54.5 and 57.4% with 1 and 4 mature follicles developed, we found a proportional relation between mature follicles and pregnancy rates. The ongoing pregnancy rates was 19.8 y 13.3% in <35 y ≥35 years respectively. The use of antGnRH does not appear to be related to better pregnancy rates in cycles with more than one mature follicle.

CONCLUSIONS:

we found a proportional relation between mature follicles and pregnancy rates. The use of antGnRH does not appear to be related to better pregnancy rates in cycles with more than one mature follicle. The target in ovarian stimulation and IUI must be the development of 2 or 3 matures follicles.