RESUMEN
The aim was to investigate the influence of various biological factors upon the outcome of intrauterine insemination (IUI). The total IUI history (856 cycles) of 352 couples was studied. Live-birth showed a strong negative correlation with female age but no correlation with male age. Antimüllerian hormone (AMH) and antral follicle count (AFC) correlated negatively with female age, and follicle stimulating hormone (FSH) correlated positively. Significant thresholds were found for all three variables, and also for total motile count (TMC) in the prepared sperm. Calculating pregnancy losses per positive pregnancy showed a strong correlation with increasing female age. This was highly significant for biochemical losses but not for fetal heart miscarriages. Male age had no effect on rate of pregnancy loss. In conclusion, female age, FSH, AMH and TMC are good predictive factors for live-birth and therefore relate to essential in vivo steps in the reproductive process.