IUI is a widely used resource for the treatment of infertile couples, with great chances for success when IUI is properly selected. Semen quality is one of the factors that contributes to the technique’s success, and among the semen parameters, sperm motility is considered an important factor for obtaining high pregnancy rates in couples that have indications for IUI treatment . Several studies have shown that progressive motility and/or total motile sperm [5–7, 9, 10, 13, 14, 16, 21, 22],[26–28] were considered the best predictors of pregnancy after sperm processing.
Pasqualotto et al. assessed 504 couples who underwent IUI to investigate the relation between the postwash TMC and postwash percentage of motility as well as to determine the minimal postwash TMC as a predictive factor of IUI success. The results indicated that, independent of the postwash TMC, the postwash motility predicted IUI success at a cutoff of 40%.
Van Weert et al. performed a meta-analysis (16 studies) to investigate the performance and clinical value of the postwash TMC as a test to predict IUI outcome. Their results indicate that the value of the postwash TMC at insemination relies on the enhancement of patient selection by identifying couples that are unlikely to conceive with IUI and not on the selection of patients that are most likely to conceive. This result occurred because there was high specificity (failure to become pregnant) of the postwash TMC, with different cutoff values for different clinics. These cut-off values probably were variable due to the different methodologies of sperm preparation in each study. However, the authors concluded that the postwash TMC could be used in counseling patients for the selection of the better treatment, either IUI or more complex methods.
When we compare our data with the literature, we believe that the success rate that was achieved in the present study (29.7% of CP rate per cycle) may be due to the adequate indication of IUI, exclusion of male and severe female factors, and to the fact that the sperm concentration and the number of motile sperm for IUI was according to the WHO reference values .
Demir et al. evaluated the effect of different sperm parameters on the pregnancy rate of IUI cycles in women with favorable fertility characteristics that were treated for infertility. Demir et al. assessed 212 infertile couples and obtained a pregnancy rate of 15.8% per cycle. The woman’s age and total number of motile sperm were predictive factors for pregnancy. The pregnancy rate was the highest in IUI cycles when woman were <25 years old, the total number of motile sperm was >10 million and morphology was >4%. Male age was also a determining factor for IUI success, even with a normal spermiogram. In our study, there was no significant difference in age (both men and women) in both groups (pregnancy and no pregnancy), and our data reinforce that sperm motility, which was verified in the present study, may help patients determine their chances of IUI success.
Currently, many studies investigate seminal parameters and its importance in achieving good pregnancy outcomes in couples undergoing IUI. However many controversies make it impossible to know which couples could benefit from this form of treatment because the basic semen analysis is not a good parameter for IUI success. Moreover, we do not have answers regarding the feasibility of selectively insisting on the IUI technique. There is only one study in the literature, which was performed by Branigan et al., that analyzed sperm motility at 24 h after processing and incubation as the predictive test of IUI success. According to the study outcome, this motility test is predictive of IUI success. The authors assessed 414 couples undergoing IUI because of a male factor and unexplained infertility. Their results showed that none of the basic semen analysis parameters of concentration, motility or morphology was predictive of IUI success. With the advanced analysis, when the processed total motile sperm that were available for IUI was ≥10 × 106 and the sperm survival at 24 h after incubation was ≥70%, 89% of the couples achieved pregnancy, with a 21.4% pregnancy rate per cycle. With the cutoff values >70% for the advanced semen analysis, the test had a sensitivity of 94% and specificity of 86%.
Interestingly the authors compared men with normal semen analysis (group of unexplained infertility) with those men presenting a male factor. The results showed that 83% of couples had male factor problems (basic semen analysis parameters), presenting a per cycle pregnancy rate of 17.8% and a 48% cumulative pregnancy rate. Twenty-three percent of men with normal semen parameters presented a per cycle pregnancy rate of 1.8% and they did not meet the advanced semen analysis cutoff values for 24 h motility or processed total motile sperm. Therefore, the advanced test was predictive, independent of normal or abnormal the basic analysis seminal parameters, because this advanced analysis accurately predicted these “occult” male factors.
This same type of test was performed in this work, but only in normospermic individuals, which allowed a good success rate in our IUI results. Some studies confirmed that pregnancy rates are higher in normospermic individuals as shown by Allen et al., which indicated a 25% pregnancy rate per cycle in 104 couples when the male factor was predominant and a 60% pregnancy rate per cycle in 58 couples when there was a cervical factor. For Grigoriou et al., the rates of CP and live births per cycle were significantly lower in the teratozoospermia group when compared with the normozoospermia group, whereas the cumulative live birth rate after 4 IUI cycles was significantly lower in the group with male factors of infertility.
These data corroborate the results presented here, indicating that high pregnancy rates are obtained in normospermic patients in which sperm motility after incubation remains unchanged. Therefore, the test with 24 h incubation at 37°C in 5% CO2 after sperm processing allowed us to conclude that motility is related to the success rate of IUI. Thus, couples seeking treatment for infertility could be subjected to this test, and from the test results, we would be able to select those couples who might benefit from IUI. Thus, couples avoid subjection to several unnecessary cycles of IUI. Successive failed attempts of the IUI can be a frustrating experience for the couple, not only by the distress between one cycle and another but also by the fear of not achieving success .
We also believe that if this predictive test of IUI success was applied to patients before treatment, then a consensus could be determined regarding the existing variation in the limit for the number of cycles to be performed. The present study aims at this goal through a cutoff value using motility, which is the parameter that appears to be the most relevant. This observation is consistent with the studies by Shulman et al., who concluded that the degree of sperm motility is the only parameter that can be correlated with the IUI outcome for normal women with a partner with good sperm motility, after appropriate sperm preparation.
The IUI is a less complex treatment and the test of sperm motility at 24 h after incubation at 37°C in 5% CO2 can be used to predict CP prior to the IUI treatment or as an indicator to verify whether a new IUI attempt must be performed or more complex ARTs are required.