Objective: This study was conducted to compare the pregnancy rates of ultrasound-guided intrauterine insemination (UG-IUI) and classical intrauterine insemination (C-IUI) cycles.

Study design: A total of 320 infertile women were enrolled and randomized into an UG-IUI group, and a C-IUI group. All participants received an oral medication for ovarian stimulation. With both groups, the IUIs were scheduled and performed by doctors in their residency and fellowship training, under supervision. The duration and difficulty of the procedures were assessed. A pregnancy test was offered 3 weeks later if the participants did not have menstruation.

Results: The demographic and other baseline characteristics of the groups (baseline hormone levels, cervical length, uterine position, endometrial thickness, and expertise of the providers) were comparable. The pregnancy rates were similar, with 6.9 % and 6.3 % for the UG-IUI and C-IUI groups, respectively. In the UG-IUI group, the pregnancy rate of the multigravida women was three times higher than that of the nulligravida women (15.4 % vs. 5.0 %; p = 0.13). Although the duration of the procedure was shorter for the UG-IUI group (p < 0.05), the level of difficulty was similar for the two groups.

Conclusions: For oral-medication stimulated cycles, UG-IUI did not increase the pregnancy rate more than with C-IUI. However, the pregnancy rate tended to increase with UG-IUI for multigravida women.