Single versus Double Intrauterine Insemination in Controlled Ovarian Hyperstimulation Cycles: A Randomized Trial

There are many factors that affect intrauterine insemination (IUI) success rate and identifying those factors can be helpful. This study aimed to investigate the single versus double IUI in controlled ovarian hyperstimulation cycles.

This is a randomized clinical trial with equal randomization (1:1) conducted on 580 women who underwent IUI in a private infertility clinic from May 2013 to November 2014 in Rasht, Iran. Women were randomly assigned to single (n = 290) or double (n = 290) IUI groups. Women in the single group underwent IUI performed 36 hours after human chorionic gonadotropin (HCG) administration. Women in the double group underwent two IUIs performed 18 and 40 hours after HCG administration. The main outcome was clinical pregnancy confirmed by evidence of fetal cardiac activity. Data were analyzed by SPSS software. Comparisons of frequencies were done using the Fisher exact test and Chi-square test. For comparing means between the two groups, the independent t-test was used. The P-value < 0.05 was considered to indicate statistical significance.

Pregnancy rate was 11.7% (34/290) in the single IUI group and 13.4% (39/249) in the double IUI group. The difference between the two groups was not statistically significant (P = 0.617, OR = 1.17, 95% CI: 0.72 - 1.91). Also, we could not show significant difference between single and double IUI groups in different cause of infertility groups regarding the success rate.

Based on findings, double versus single IUI did not increase the pregnancy rate of IUI and further investigations are recommended.