**6. IMSI should not be used for all**

**4. IMSI in patients with a high rate of sperm DNA fragmentation**

spermatozoa with the lowest morphology score [35].

the removal of the acrosome reaction-resistant spermatozoa.

**5. IMSI and head-sperm vacuoles**

208 Spermatozoa - Facts and Perspectives

DNA integrity was assessed by Hazout et al. in 72 patients, referred to IMSI and ICSI. DNA fragmentation rate was evaluated by TUNEL assay. Improvement of clinical outcomes was evident both in patients with an elevated degree of sperm DNA fragmentation and in those with normal sperm DNA status [36]. Similar results were obtained by de Almeida Ferreira Braga et al. and Setti et al., who showed that fertilization and high-quality embryo rates were similar in patients with a high incidence of sperm DNA fragmentation tested in sibling oocytes split into ICSI and IMSI. Their observation suggested that IMSI, but not DNA sperm fragmentation assay per se, could be a beneficial tool in improving IVF-ICSI results [41, 42]. In another independent study no correlation was found between abnormal sperm head morphology as assessed by high magnification (score 0) and DNA fragmentation. However, the rate of chromatin decondensation of their score 0 spermatozoa was twice as high as the spermatozoa that scored 4–6 (19.5% vs. 10.1%; *P* < 0.0001) [43]. This finding might explain the former observation of these researchers that no expanded blastocyst was developed following the injection of

Vanderzwalmen et al., classified the spermatozoa according to the presence and size of vacuoles into four groups: Grade I: normal shape and no vacuoles; Grade II: normal shape and maximum of two small vacuoles; Grade III: normal shape and more than two small vacuoles or one large vacuole; and Grade IV: large vacuoles in conjunction with abnormal head shapes or other abnormalities at the level of the base of the sperm head. The outcome of embryo development in a group of 25 patients after sibling oocyte injection with the four different grades of spermatozoa showed no significant difference in embryo quality up to day 3. However, the occurrence of blastocyst formation was 56.3 and 61.4% with grade I and II spermatozoa, respectively, compared with 5.1% with grade III and 0% with grade IV, respectively (*P* < 0.001) [44]. It is not clear yet why presence of vacuoles in the sperm head is such an important parameter of sperm quality. Some reports showed no correlation between the appearances of vacuoles to male infertility [45–47]. One of these studies was an unpowered investigation [47] and another evaluated the sperm under magnification of 1000× [45]. Many others reported that vacuoles might negatively be associated with male fertility potential [32–37, 44, 48–54]. Moreover, investigation of the relation between sperm vacuoles and acrosome reaction suggested that there might be a negative link between presence of vacuoles and acrosome reaction of the sperm [55, 56]. Consequently, IMSI could be a method for assisting

The personal attitude of the authors of the current dissertation is that majority of abnormalities observed under the high magnification of IMSI in real time are probably not visible while using routine conditions with lower magnifications. It is likely, though, that the benefit of scoring scale of the sperm cell is a kind of "fine tuning"; IMSI therefore is more beneficial for motile spermatozoa which have normal morphological appearance under magnification 200–400×.

It seems that IMSI was a promising revolutionary technique in terms of improving the outcome of ICSI treatments. One might agree that high magnification achieved by the technique contributes with a better evaluation of the aspirated sperm cell for the injection providing encouraging results. On the other hand, prolonged sperm manipulation, special instrumentation, additional number of embryologists who should be trained and expertly perform the technology, and the additional cost for the patients might increase the cost effectiveness of the procedure. Taking all the above into consideration, patients should be given counseling to undergo IMSI, for a better chance to conceive.

It appears that there is no advantage or benefit over standard ICSI in terms of clinical outcome in an unselected infertile population. Although there were trends for higher implantation, clinical pregnancies, and live birth rates in the IMSI group, using the technique did not reveal an improvement in the clinical outcome compared with ICSI [57, 58]. The authors of the current publication, therefore, will try to discuss the benefits of IMSI in cases of patients with repeated implantation failures, severe male factor infertility, and advanced paternal and maternal age.

#### **6.1. Patients with repeated implantation failures**

Sixty-two couples with at least two previous consequent pregnancy failures after routine ICSI cycles underwent IMSI in the following cycle. The matched control group comprised 50 couples, who underwent routine ICSI treatment and previously experienced the same number of ICSI failures in the same center. Fertilization and top-quality embryo rates were similar in both groups. A higher pregnancy rate with a lower miscarriage rate were achieved in the IMSI group, in comparison to the control group (66.0% vs. 30.0%; *P* < 0.01; 33.0% vs. 9.0%; *P* < 0.01, respectively) [33]. Following that study, this new concept of sperm selection prior to ICSI was undertaken in additional centers, with encouraging results. Efficacy of IMSI was examined, for instance, in 12 couples with two or more repeated conventional ICSI failures, who underwent an additional conventional ICSI attempt, followed by a high magnification IMSI attempt. Fertilization and cleavage rates and embryo morphology were similar when we compared the two sequential attempts (ICSI attempt vs. the following IMSI cycle). However, improved clinical outcomes such as implantation, pregnancy, delivery, and birth rates were observed in IMSI attempts when compared with ICSI (20.3% vs. 0.8%, 37.6% vs. 2.4%, 33.6% vs. 0.0%, 17.6% vs. 0.0%, respectively; *P* < 0.001) [36]. Another metaanalysis compared the outcomes of conventional ICSI vs. IMSI cycles. It was concluded that IMSI not only improves the percentage of top-quality embryos, implantation, and pregnancy rates but also reduces miscarriage rates as compared with ICSI [59]. Findings of a retrospective study in 42 couples supported the former as well. These scientists examined the efficiency of the IMSI technique in patients with at least three repeated IVF-ICSI failure. The investigators demonstrated superior implantation, clinical pregnancy, and live birth rates in the IMSI group, moreover a lower miscarriage rate [60]. These data, in addition to the abovementioned, pointed toward IMSI as an important tool for the selection of the best spermatozoon for the injection of oocytes in cases of repeated IVF treatment failure.

#### **6.2. IMSI in cases of severe male factor infertility**

Usage of IMSI had a significant contribution to the accumulated knowledge of male infertility. At present, few randomized controlled trials are available assessing the advantages of IMSI over the conventional ICSI procedure. Antinori et al. assessed 446 couples, randomly referred to ICSI or IMSI, with at least 2 previous diagnoses of male factors due to severe oligoasthenoteratozoospermia [53]. Despite their initial poor reproductive prognosis, patients with two or more previous failed attempts benefited the most from IMSI not only in terms of increased pregnancy rate (29.8% vs. 12.9%; *P* = 0.017) but also lower miscarriage rates. Patients diagnosed with poor reproductive prognosis with two or more previous failed attempts benefited the most from IMSI. Study of patients with motile sperm less than 0.1 × 106 /ml after the swim-up technique showed a positive influence of IMSI on fertilization, implantation, and pregnancy rates [42, 61]. More reports regarding patients with isolated teratozoospermia or severe oligospermia pointed to the benefits following the selection of injected sperm cell using IMSI. Higher clinical pregnancy and higher implantation rates were observed, in comparison to the conventional aspiration of spermatozoa in ICSI [62, 63].

There was an increased incidence for sex chromosome aneuploidy in ICSI embryos when compared with IMSI (23.5% vs. 15.0%, respectively). IMSI was associated with a lower risk of sex chromosome abnormalities (odds ratio 0.57; confidence interval 0.37–0.90). The incidence of chaotic embryos was also higher with the ICSI procedure in comparison to IMSI (27.5% vs. 18.8%). An unexpected difference in gender incidence rates of euploid embryos was detected. The latest was supported by Setti et al., when a higher incidence of XX embryos derived from IMSI cycles in comparison with ICSI was noticed (66.9% vs. 52.5%, respectively) [42]. It is possible that IMSI-selected "normal" spermatozoa may carry a higher proportion of the X

Interacytoplasmic Morphologically Selected Sperm Injection: A Tool for Selecting the Best…

http://dx.doi.org/10.5772/intechopen.73388

211

Data also demonstrated a consistent decline in semen quality, as reflected by morphological evaluation by high-power microscope magnification, with increased age, suggesting the use

Regarding the question of sperm quality in correlation to male age, it was described that increased male age is associated with a decrease in semen volume of 3–22%, a decrease in sperm motility of 3–37%, and a decrease in percentage of normal sperm of 4–18%, when comparing 30-year-old men with 50-year-old men, with no consistent effect on sperm concentration. Moreover, with control for a female partner, a relative decrease in pregnancy rates of 23 and 38%, increased risks for subfecundity ranging from 11 to 25%, and relative increase in months to achieve pregnancy up to 20% were found, comparing men <30 years old with men >50 years old, respectively [66]. Recently, IMSI provided remarkable information. Considering assessment of semen samples from 975 men who underwent IMSI, two forms of spermatozoa were considered: normal spermatozoa and spermatozoa with large nuclear vacuoles (LNV) [67]. At least 200 spermatozoa per sample were evaluated and the percentages of normal and LNV spermatozoa were determined. The subjects were divided into three groups according to age: Group I ≤ 35 years old; Group II: 3640 years; and Group III ≥ 41 years. Ratio of normal sperm cells in the older group (Group III) was lower than in the younger groups (I and II; P < 0.05). Percentage of LNV spermatozoa was higher in the older group (III) than in the younger (I and II) groups (*P* < 0.05). Regression analysis demonstrated a decrease in the incidence of normal sperm with increasing age (*P* < 0.05; r = −0.10). There was a positive correlation between the percentage of spermatozoa with LNV and male age (*P* < 0.05, r = 0.10). These results demonstrated a consistent decline in semen quality, as reflected by morphological evaluation following IMSI with increased age, and support the routine use of IMSI for ICSI

The introduction to IMSI enabled to morphologically evaluate the individual motile sperm cell prior to its injection into the oocyte. The possibility to correlate each injected spermatozoon

chromosome, which might lead to such findings.

**7.1. IMSI and paternal age**

**8. Conclusions**

of IMSI as routine in the older group of patients [66, 67].

as a criterion for semen analysis in older group of patients.
