Intracytoplasmic Sperm Injection Fertilization Rate Research Articles

Sperm chromatin structure assay (SCSA®) parameters relationship with fertilization rate, blastocyst development and pregnancy outcomes following in vitro fertilization (IVF) and IVF with intracytoplasmic sperm injection (ICSI)

Objective: To determine the prognostic value of the DNA Fragmentation Index (DFI) and High DNA Stainability (HDS) for fertilization rate, blastocyst development, spontaneous abortions, and chemical and ongoing pregnancies following conventional IVF and IVF with ICSI. Design: Two-hundred-forty-nine couples (female age; 34 ± 4, 25 - 48 yrs) undergoing their first IVF and/or ICSI cycle at a private IVF clinic were included in this combined retrospective review and prospective study. Materials and Methods: Conventional semen parameters were evaluated including semen volume and sperm count, motility and morphology by World Health Organization guidelines (WHO, 1992). An aliquot of the pre-wash semen was frozen for the SCSA, a flow cytometric test that identifies sperm with a high susceptibility to acid-induced nuclear DNA denaturation (DFI) and high DNA stainability (HDS) in situ. Following conventional IVF and ICSI (75% of couples), ICSI only (18%) or conventional IVF only (7%), fertilization was assessed at 16–18 hours post insemination or injection. Blastocysts were graded according to Gardner and Schoolcraft’s system and up to 2 transferred on day 5. Pearson’s Chi-Square Test was used to measure the relationship between high and low DFI (≥30% DFI vs. <30% DFI) and HDS groups (≥15% HDS vs. <15% HDS) and the presence of male factors and IVF/ICSI. Results: IVF and ICSI fertilization rates were not statistically different between the high and low DFI groups. However, a significantly higher percentage of men with ≥15% HDS had low (<25%, p < 0.001) and moderately low (<50%, p < 0.01) IVF fertilization rates. HDS was not related to ICSI fertilization rates. HDS did not significantly impact later embryo development or pregnancy outcomes following IVF or ICSI. Men with ≥30% DFI had a higher risk of having male factors (p < 0.001), poor blastocyst rates (<30%; p <0.003) and no ongoing pregnancy >12 weeks (p < 0.01). WHO thresholds for abnormal volume, count, motility and morphology were not predictive of ongoing pregnancy. Conclusion: The relationship between HDS and poor IVF fertilization rates provides preliminary evidence that ICSI may be indicated in men with ≥15% HDS. Men with high (≥30% DFI) levels of DNA fragmentation were at greater risk for low blastocyst rates and failure to initiate an ongoing pregnancy. The SCSA provides valuable prognostic information to physicians counseling couples prior to IVF and/or ICSI cycles.

Statistical analysis of factors affecting fertilization rates and clinical outcome associated with intracytoplasmic sperm injection

ObjectiveTo identify and evaluate the statistically significant predictors of intracytoplasmic sperm injection (ICSI) fertilization rates and clinical pregnancy in a single population using appropriate statistical techniques. DesignRetrospective study. SettingFertility and Endocrinology Center, University of Washington Medical Center, Seattle, Washington. Patient(s)Four hundred forty-one patients undergoing their first attempt at IVF-ICSI from January 1, 1999, to May 21, 2001. Intervention(s)Each ICSI procedure for an individual patient was performed by a single operator. Sperm parameters, oocyte age, culture condition, ICSI technique, and ICSI operator were assessed as variables influencing the fertilization rate. We also assessed the impact of patient age, serum E2 concentration on the day of hCG administration, embryo quality, and number of embryos transferred on the probability of achieving a clinical pregnancy. Main outcome measure(s)Fertilization rate and clinical pregnancy. Result(s)The 2 pronuclei (2PN) rate was significantly correlated with sperm motility, and there were significant differences in the 2PN rates among the ICSI operators. There was no difference in the 2PN rate among different sperm types or among the eight laboratory incubators or whether the eggs were cultured individually or in groups. Patient age, serum E2 concentration on the day of hCG administration, embryo quality, and number of embryos transferred were all statistically significant predictors of clinical pregnancy. Conclusion(s)In our program, sperm motility and ICSI operator are the two most important predictors for the ICSI fertilization rate in vitro. Patient age, serum E2 concentration on the day of hCG administration, embryo quality, and number of embryos transferred were all statistically significant predictors of clinical pregnancy.

Real-time fine morphology of motile human sperm cells is associated with IVF-ICSI outcome.

The aim of the present prospective study was to determine whether subtle sperm morphological characteristics affect the outcome of intracytoplasmic sperm injection (ICSI), and if so, to identify those that are relevant. For this purpose, we developed a new method, the motile sperm organelle morphology examination (MSOME). The examination is performed in real time using an inverted light microscope equipped with high-power Nomarski optics enhanced by digital imaging to achieve a magnification up to 6300x. MSOME was applied to the leftover sperm fraction selected for microinjection in 100 random couples referred for ICSI treatment at 3 major in vitro fertilization centers. We found that the morphological normalcy of the entire sperm cell, according to MSOME criteria, was positively associated with ICSI fertilization rate (area under the receiver operating characteristics [ROC] curve, 88%) but not with pregnancy outcome. The morphological normalcy of the sperm nucleus, defined by MSOME, was significantly and positively associated with both fertilization rate and pregnancy outcome (areas under the ROC curve, 72% and 74%, respectively). These findings indicate that ICSI-associated pregnancy rate may be affected by subtle morphological malformations of the sperm nucleus, which may remain undetected by the embryologist during the routine selection procedure.

Better fertilization rates with intracytoplasmic sperm injection (ICSI) in unexplained infertility.

Objective: Intracytoplasmic sperm injection (ICSI) has been applied in patients over forty, in tubal infertility, and some have suggested it as the treatment of choice in all in vitro (IVF) cases. Reduced fertilization rates have been documented in IVF cycles done for unexplained infertility. The possible role of ICSI to avoid these fertilization failures in the first IVF attempt has been advocated before. Our objective was to compare the fertilization rates in IVF and ICSI applied on sibling oocytes in unexplained infertility cases. Design: A retrospective analyses was carried out on 161 cases of unexplained and tubal infertility, between January 1997 and December 2000, in which sibling oocytes were subject to two insemination techniques: some were injected with semen by the ICSI procedure and others were inseminated by conventional IVF, using the same sperm preparation. Materials/Methods: Patients included in the study received ovarian stimulation treatment in acceptable protocols, using gonadotropin releasing hormone analogs (GnRHa) and different menotropins. Transfer of embryos was performed either, 48–72 hours after retrieval or at the blastocyst stage. Fertilization rates, embryo quality, as well as pregnancy rates, were compared and analyzed using the SPSS software. Results: The average rate of fertilization of all sibling oocytes, using IVF and ICSI, were 0.5653 and 0.7115, respectively. The difference in fertilization rate, analyzed by paired T-test, was 0.1462 (SD = 0.4232, 95% confidence interval 0.0802–0.2120, p < 0.0001). In 26 cycles (16.1%) total failure of fertilization was observed, using IVF, where as no such failures were noted in the ICSI-inseminated oocytes. Total motile cell in each couple, had no correlation with the difference in fertilization rates. Rates of pregnancy were not significantly different in ICSI, IVF and mixed embryo transfers, accordingly: 44.2%, 54.9%, and 45.9%. There was no significant difference (p = 0.846) in IVF and ICSI fertilization rates between embryo transfers which resulted in pregnancy and those which did not. Conclusions: Our results indicate that ICSI has an advantage over standard IVF in unexplained infertility cases. As such, we suggest that at least half the oocytes be exposed to ICSI in order to obtain information on the sperm’s potential to fertilize the oocytes and prevent total failure of fertilization in the first attempt of such cases.

Morphology of testicular spermatozoa obtained by testicular sperm extraction in obstructive and nonobstructive azoospermic men and its relation to fertilization success in the in vitro fertilization-intracytoplasmic sperm injection system.

The aim of the present study was to evaluate the morphology of testicular spermatozoa by 3 different determinants. Sperm cells were obtained and their morphology was evaluated from 27 testicular sperm extraction (TESE) operations, of which 20 men had nonobstructive azoospermia and 7 had obstructive azoospermia. In 17 cases, 2 biopsies were obtained from 2 different locations of the testis. Only mature spermatozoa presenting full-grown tail (tail dimension about 10-fold greater than the head dimension) were counted. Three characteristics of sperm morphology were evaluated: head dimensions, and acrosome and midpiece irregularities. The percentage of sperm cells with normal morphology (considering the 3 characteristics) in specimens from patients with obstructive and nonobstructive azoospermia were 47% +/- 4.6% and 29 +/- 1.8%, respectively (P < .01). The percentage of spermatozoa with normal head dimensions were 76% +/- 3.2% and 63% +/- 2.6% (P > .05), those with normal acrosome were 58% +/- 4.6% and 41% +/- 3.4% (P < .05), and those with normal midpiece were 74% +/- 4.1% and 67% +/- 1.6% (P > .05), in obstructive and nonobstructive azoospermia, respectively. No significant differences were observed in sperm morphology between different locations of the testis. Sperm morphological characteristics were not associated with fertilization rate in intracytoplasmic sperm injection (ICSI). Follicle-stimulation hormone and luteinizing hormone were inversely correlated with normal morphology of testicular spermatozoa (r = -0.49 and r = -0.47, respectively; P < .05). It can be concluded that a relatively high portion of testicular sperm are morphologically normal. The higher rate of normal spermatozoa in obstructive azoospermia compared with nonobstructive spermatozoa suggests that the factors leading to azoospermia may affect testicular sperm morphology. The morphological characteristics of testicular sperm do not affect fertilization rate in ICSI.

Effect of injected spermatozoa morphology on the outcome of intracytoplasmic sperm injection in humans

Effect of injected spermatozoa morphology on the outcome of intracytoplasmic sperm injection in humans

Fertilization failures and abnormal fertilization after intracytoplasmic sperm injection.

This study addresses the incidence of failed (0%) and suboptimal (<50%) fertilization after intracytoplasmic sperm injection (ICSI), variation in the ICSI fertilization rate for specific couples, and the causes of fertilization failure and abnormal fertilization after ICSI. Failed fertilization occurred in only 37 of 1343 cycles (3%). The risk of failure was highest (37%) when only one oocyte was injected, and was lowest (0.8%) when five or more oocytes were collected. The incidence of suboptimal fertilization and the variation in the fertilization rate were studied in 87 couples who each had three cycles of ICSI in which four oocytes were injected with ejaculated spermatozoa. Approximately 74% of these couples achieved >50% fertilization in every cycle. Only 26% of the couples had <50% fertilization in one or more cycles, and most of these (17%) had only a single cycle with suboptimal fertilization. Only four of the 87 couples (5%) had suboptimal fertilization in all three cycles. The difference between the maximum and minimum fertilization rate for a couple was used as an index of variation of the fertilization rate. It was found that 47 couples (54%) had 0-25% variation, 33 couples (38%) had 26-50% fertilization and only seven couples (8%) had >50% variation. The causes of failed and abnormal fertilization were studied in unfertilized and abnormally fertilized oocytes after staining with Hoechst 33342. In total, 1005 unfertilized oocytes were studied, of which 828 (82%) were still at metaphase II and 177 (18%) were activated. Most of the oocytes (83%) contained a spermatozoon and, in the majority of these oocytes, the sperm head was partially or completely decondensed. Hence, failure of oocyte activation was the principal cause of fertilization failure. A similar pattern was observed in activated, unfertilized oocytes, although there was a higher incidence of intact spermatozoa in these oocytes compared with metaphase II, unfertilized oocytes. Interestingly, 56% of the activated oocytes contained a decondensed sperm head which was not processed into a male pronucleus. A total of 169 abnormally fertilized oocytes was also studied. Two anomalies were found: digyny due to retention of the second polar body and its subsequent transformation into a third pronucleus, and abnormal pronuclear size and number.

Sperm Deoxyribonucleic Acid Fragmentation is Increased in Poor-Quality Semen Samples and Correlates with Failed Fertilization in Intracytoplasmic Sperm Injection

Objective: To determine the incidence of DNA fragmentation in human sperm used for intracytoplasmic sperm injection (ICSI) and to correlate any detected DNA damage with semen analysis parameters and fertilization rates in ICSI. Design: Descriptive and correlational clinical study. Setting: Tertiary care fertility clinic. Patient(s): A total of 150 semen samples was collected from men in the ICSI program. Intervention(s): For each sample, sperm wash and swim-up were performed, and the percentage of recovered sperm with DNA fragmentation was determined with the use of terminal transferase-mediated deoxyuridine triphosphate-biotin end labeling. Main Outcome Measure(s): The percentage of sperm with DNA fragmentation was correlated with semen analysis parameters and ICSI fertilization rates. Result(s): The mean (±SD) percentage of sperm with fragmented DNA was 14.5% ± 1.5% and ranged from 0.5% to 75%. A significant negative association was found between the percentage of sperm with DNA fragmentation and the ICSI fertilization rate. We also observed that the motility and morphology of the ejaculated sperm were correlated negatively with the percentage of DNA fragmentation in the washed sperm recovered by the swim-up technique. Conclusion(s): Our results suggest that when poor-quality semen samples are used for ICSI, there is a greater likelihood that some sperm selected for injection, despite appearing normal, contain fragmented DNA. Whether sperm DNA damage may contribute to failure of pronuclear formation and embryo development in some apparently unfertilized ICSI oocytes is unclear.