Background: The aim was to ascertain whether using ultrasound guidance during intrauterine insemination (IUI) could increase pregnancy rates (PRs).
Methods: The population under study consisted of 73 consecutive couples subjected to IUI in our Human Reproduction Unit, between June and December 2006, with a total of 231 IUI cycles performed. The patients were randomized using a computer-generated random numeric table into two groups: ultrasound-guided IUI group (n = 33) and clinical IUI group (n = 40).
Results: The PR was 16.0% per cycle in ultrasound-guided IUI and 16.8% in the control group, no statistically significant differences being observed between the groups. The 95% confidence interval for the difference in PRs of 0.8% was -8.8 to 10. There were no differences in PR per woman, nor in first-cycle PR. The cumulative PR was also similar in both populations. Although the initial intention was to perform a study involving a larger number of cases, after a first interim analysis, the study was interrupted due to its futility. There were no differences in PR according to the different cervico-uterine angles.
Conclusions: Ultrasound-guided IUI does not produce better results than blind insemination, because the PR per cycle is similar. ClinicalTrials.gov ID NCT00809952.