the effect of intra-catheter air volume on the outcome of intrauterine insemination (iui): a clinical trial study

Background & objective: the presence of air in the catheter was found to affect the success of embryo transfer into the uterine cavity. this study determined the chances of achieving pregnancy using the intrauterine insemination (iui) method with different air volumes inside the iui catheter. materials & methods: this clinical trial study was performed on 521 iui cycles among 270 couples from 2013 to 2014. the patients were divided into three groups (each group of 90 patients), based on three volumes of air inside the catheter (0.0 ml, 0.5 ml, and 1 ml). other variables, include the woman’s age, menstrual cycle status, duration of infertility, type of infertility, sperm morphology, total motile sperm count (tmsc), number of motile sperm inseminated (nmsi), and pregnancy rate or the success rates of iui were evaluated. results: the mean age of women and men were 33 and 30 years, respectively. based on three volumes of air inside the catheter (0.0 ml, 0.5 ml, and 1.0 ml), the pregnancy rates were 5%, 9.4%, and 16.5%, respectively. tmsc of more than 5.6x106 and nmsi of more than 3.4x106 were associated with the chance of iui achievement. at the same time, there was no significant relationship between the woman’s age, irregular menstrual cycles, and duration of infertility with the success rate of iui. we found that the air volume of 1.0 ml inside the iui catheter significantly increased the pregnancy rate compared to other groups. conclusion: the volume of air within the catheter had a significant relationship with the success rate of iui.