Previous Fertilization Failure Research Articles

Should ICSI be the treatment of choice for all cases of in-vitro conception? No, not in light of the scientific data.

There is an ongoing debate among reproductive endocrinologists and embryologists about the indications for ICSI in the management of the infertile couple. Analysis of published results indicates that there are no data to suggest that ICSI should be performed in all cases of in-vitro conception. If the results of the basic semen analysis and sperm function tests demonstrate an impairment of sperm fertilizing capacity, couples should be directed to ICSI. In cases of previous fertilization failure, ICSI usually results in an improved outcome. This suggests the presence of 'occult' male or female gamete defects that can be bypassed by ICSI. We stress that efforts should be geared toward the identification of the aetiology and pathophysiology of sperm and oocyte lesions/dysfunctions responsible for fertilization impairment and their potential contributions to defective embryogenesis. A better definition of the indications for ICSI is needed, together with the development of directed, simpler, less expensive and safer alternatives.

Intracytoplasmic sperm injection overcomes previous fertilization failure with conventional in vitro fertilization

Objective: To evaluate the outcome of intracytoplasmic sperm injection (ICSI) in patients with previous idiopathic fertilization failure (≤20% fertilization rate) after conventional IVF. Design: Retrospective analysis. Setting: IVF program at a university medical center. Patient(s): Twenty-five patients who underwent 38 ICSI cycles after experiencing unexplained fertilization failure with conventional IVF (group A) and 87 patients who underwent 118 ICSI cycles for male factor indications during the same period (group B). Intervention(s): Intracytoplasmic sperm injection was performed in a subsequent cycle after fertilization failure with conventional IVF. Main Outcome Measure(s): Outcomes of IVF were compared between groups A and B. Result(s): Fertilization was achieved with ICSI in all patients with previous fertilization failure. The mean (±SD) fertilization rate (68% ± 21% vs. 64% ± 22%), implantation rate per embryo (22.6% vs. 20%), and delivery rate per cycle (47.3% vs. 49.1%) did not differ significantly between groups A and B. Overall, 72% of patients with previous unexplained fertilization failure had a successful pregnancy after ICSI. Conclusion(s): Intracytoplasmic sperm injection can overcome unexplained fertilization failure caused by a potentially occult gamete abnormality, with the same fertilization, implantation, and pregnancy rates as are seen in patients with abnormal sperm parameters.

Intracytoplasmic sperm injection is not associated with poor outcome in couples with normal semen parameters and previous idiopathic fertilization failure in conventional in vitro fertilization

In this study, we compared the results of intracytoplasmic sperm injection (ICSI) in patients with normal semen parameters and a history of failed fertilization with conventional IVF (study group) and in patients with male factor infertility (control group). Patient and cycle characteristics were similar in both groups. The mean number of retrieved and metaphase II oocytes, fertilized oocytes, embryos developed, embryos transferred and the number of cycles with fertilization failure also did not differ between groups. Although differences were not statistically significant, pregnancy rate (56.3% vs. 31.5%), implantation rate (14.2% vs. 12%) and ongoing pregnancy rate (37.5% vs. 17.7%) per embryo transfer were higher in the study group than the ones in the control group. We concluded that previous idiopathic fertilization failure with conventional IVF is not associated with poor outcome in subsequent ICSI treatment.

Previous fertilization failure with conventional in vitro fertilization is associated with poor outcome of intracytoplasmic sperm injection

Objective: To evaluate the outcome of intracytoplasmic sperm injection (ICSI) in patients with a history of fertilization failure with conventional IVF. Design: Retrospective analysis of 2 years of clinical experience with ICSI. Setting: Clinical IVF-ET program in a tertiary care referral center. Patient(s): The results of ICSI performed between January 1995 and December 1996 were compared between patients with normal semen parameters and a history of fertilization failure (<20% of oocytes) with conventional IVF and patients with male factor infertility. Intervention(s): In vitro fertilization with ICSI. Main Outcome Measure(s): Parameters examined included oocyte survival, fertilization, embryo cleavage, implantation rates, and clinical pregnancy rates. Result(s): Fertilization was achieved with ICSI for all patients during the study period. Although oocyte survival and fertilization did not differ between groups, the pregnancy and implantation rates for patients with a history of idiopathic fertilization failure (20% and 6%, respectively) were significantly lower than those for other patients undergoing ICSI (47% and 22%), respectively). Conclusion(s): The outcome of ICSI varied depending on the indication for treatment. Patients who had a history of failed or poor fertilization in vitro with apparently normal semen parameters had significantly lower pregnancy and implantation rates than did patients with either obstructive azoospermia or impaired semen quality.

Microdeletions of the Y chromosome and intracytoplasmic sperm injection: from gene to clinic.

Intracytoplasmic sperm injection (ICSI) is a successful treatment option for severe male infertility, although the aetiology of the disorder remains unclear in most cases. Recently, microdeletions in the AZF region of the Y chromosome have been detected in men with azoospermia or severe oligozoospermia. In this study we investigated the prevalence of microdeletions in the AZF region of the Y chromosome in a population of men undergoing ICSI, and looked for clinical characteristics of men with and without this deletion. Blood was drawn from 164 men, who were on the waiting list for ICSI treatment: 19 were azoospermic, 111 oligozoospermic and 34 normozoospermic (after previous total fertilization failure). A total of 100 men with proven fertility served as a control. Microdeletions in the AZFc region were present in seven of the 111 oligozoospermic men (6.3%). Compared with oligozoospermic men without microdeletions, men with microdeletions had a lower concentration of follicle stimulating hormone (FSH), a lower number of motile spermatozoa and a lower frequency of abnormal findings at andrological history or examination. No microdeletions were found in the azoospermic, normozoospermic and control groups. In conclusion, microdeletions in the AZFc region are relatively frequently found in men with severe unexplained oligozoospermia. In the ICSI era this finding has an important impact because this form of male infertility is now potentially hereditary. Therefore we recommend DNA screening (and genetic counselling) before ICSI, especially in men with normal FSH, severe oligozoospermia and no abnormal clinical andrological findings.

Intracytoplasmic sperm injection does not overcome an oocyte defect in previous fertilization failure with conventional in-vitro fertilization and normal spermatozoa.

A cohort comprising a total of 447 oocyte aspirations due to male factors (n = 258) or to previous fertilization failure by IVF in the presence of normal sperm parameters (n = 189) was studied. We found a significantly reduced implantation and pregnancy rate per transfer in the group with previously failed IVF attempts compared to the male factor group (P < 0.001). No differences were found in age, number of oocytes retrieved, number of embryos transferred or quality of embryos scored at the time of transfer. However, the fertilization and cleavage rates were found to be reduced in the group with previous failed IVF cycles. It is therefore concluded that previous fertilization failure despite normal sperm parameters in an IVF cycle may not be alleviated by the intracytoplasmic sperm injection (ICSI) procedure. These patients might suffer from oocyte defects as well.

Female age is an important parameter to predict treatment outcome in intracytoplasmic sperm injection

To assess the results obtained in our clinic with intracytoplasmic sperm injection (ICSI) in severe male factor infertility and failed fertilization and to determine if the age of the female has any impact on those results. Retrospective study. Private high-complexity Human Reproduction Center. One hundred five couples with a total of 114 procedures. Eighty-six were classified as severe male factor and 19 were classified as previous failed fertilization. Treatment was performed by ICSI. Normal fertilization, cleavage, and implantation, total, term, and ongoing pregnancy rates in the total population and in different age brackets. Excellent fertilization, cleavage, and implantation rates were obtained with this procedure (78%, 85%, and 13.5%, respectively). The total pregnancy rates were 43% and 46% per cycle and per transfer and 31.5% and 33.6% in terms of term and ongoing pregnancy rates. A significant reduction in implantation and total, and term and ongoing pregnancy rates was seen after the age of 35 years. The results obtained with ICSI are quite satisfactory with proper equipment and careful training. The age of the female is an important parameter in determining prognosis and treatment outcome.

Two essential steps for a successful intracytoplasmic sperm injection: injection of immobilized spermatozoa after rupture of the oolema.

A total of 740 cycles of intracytoplasmic sperm injection (ICSI) were performed: 625 cycles when < 6 x 10(5) total motile spermatozoa were harvestable from the ejaculate and 115 cycles in cases with a history of previous fertilization failure after classic in-vitro fertilization or subzonal sperm injection. An average of two pronuclei were observed in 63% of the injected oocytes, allowing 725 transfers of a maximum of three embryos (98%). Of 214 pregnancies initiated, 179 were established (25% of ICSI attempts). Because the fertilization rates from our initial 80 ICSI cycles were 2-fold less than those achieved previously, we changed the injection procedure and analysed, in 740 ICSI attempts, the importance of interfering technical factors and how to establish a successful ICSI programme. A remarkable change in the fertilization rate up to 68% (595 cycles) occurred when two steps in the injection procedure were performed well, i.e. immobilization of the spermatozoon and placement of the spermatozoon into the ooplasm after cytoplasmic aspiration into the pipette until oolema rupture. This immobilization, by touching the tail with the pipette, is mandatory for increasing the percentage of fertilization, even with totally non-motile spermatozoa (41%). Because aspiration of the cytoplasm is an invasive part of the ICSI procedure and influences the quality of the embryos, it is essential to reduce the amount of cytoplasm drawn into the pipette. This could be attained by using a spikeless injection pipette with the smallest possible internal diameter.

The effect of sperm parameters on the outcome of intracytoplasmic sperm injection

To investigate the influence of sperm parameters on the fertilization and pregnancy rates in intracytoplasmic sperm injection (ICSI). A retrospective analysis of 130 cycles of ICSI performed for the treatment of male factor infertility. The Egyptian IVF-ET Center. One hundred thirty couples with the diagnosis of male factor infertility or with previous failed fertilization in conventional IVF or subzonal sperm injection. Ovum pick-up and ICSI. Fertilization and pregnancy rates in relation to different semen parameters. A total of 1,433 oocytes were retrieved and 1,071 metaphase II oocytes were injected. Normal fertilization occurred in 620 oocytes (58%). Embryo transfer was done for 128 (98.5%) patients, and a total of 46 (35%) clinical pregnancies were achieved. There was no statistically significant difference in the fertilization or pregnancy rates between patients who had previously failed fertilization in conventional IVF, patients with subfertile semen, patients with semen between 1 and 10 x 10(6)/mL, and patients with semen < 1 x 10(6)/mL. There was also no significant difference in the fertilization and pregnancy rates between patients with < 95% or > 95% teratozoospermia. In ICSI, the fertilization and pregnancy rates are not affected by different semen parameters as long as morphologically well-shaped live sperms could be used for the injection.

Successful use of pentoxifylline in male-factor infertility and previous failure of in vitro fertilization: A prospective randomized study

Our objective was to determine whether the use of pentoxifylline (PF) would improve the in vitro fertilization (IVF) rate and outcome in couples with male factor infertility and previous failure of fertilization in vitro. This prospective randomized controlled study was conducted in an assisted conception unit. Forty-nine couples with previous failed fertilization in vitro attributable to male factor or male-factor infertility without previous IVF were recruited for the study. Controlled ovarian hyperstimulation was performed using a combination of gonadotropin releasing hormone agonist and human menopausal gonadotropin. Oocytes of the same grade and maturity were inseminated with spermatozoa treated with PF or control spermatozoa. A maximum of three embryos was replaced after 48 hr and all other embryos were cryopreserved. Pregnancy outcome was followed up and evidence of fetal or neonatal anomalies reported. A significantly higher fertilization rate occurred in the group where oocytes were inseminated with spermatozoa treated with PF compared with controls (56.3 versus 30.7%; P < 0.05). Fertilization occurred in 45 of the 49 cycles (92%). In seven cycles, only the oocytes that were inseminated with spermatozoa treated with PF fertilized, in contrast to only one cycle where the oocytes inseminated with control sperm fertilized (P < 0.05). Fifty-seven PF and 31 control embryos were replaced and 11 clinical pregnancies occurred. Three of the pregnancies occurred in the seven cycles in which only PF embryos were replaced, one in the single cycle where control embryos were replaced and seven from the 37 cycles in which both PF and control embryos were replaced. There was no evidence of congenital malformations in any of the offsprings resulting from this study. This study suggests that PF improves the fertilization rate and outcome in couples with male factor infertility and poor fertilization rates. This study does not suggest any increase in teratogenicity or evidence of congenital malformations in pregnancies following IVF cycles where PF was used.

In vitro fertilization in couples with previous fertilization failure using sperm incubated with pentoxifylline and 2-deoxyadenosine

To evaluate whether incubation of spermatozoa with both pentoxifylline and 2-deoxyadenosine would improve fertilization rates in couples with previous IVF failure. Autocontrolled design in which sibling oocytes were inseminated at random in vitro with spermatozoa treated or not treated by pentoxifylline and 2-deoxyadenosine. Oocyte quality, sperm motility, fertilization in vitro, and embryo quality. Sperm motility was found optimized by metabolic stimulation using pentoxifylline and 2-deoxyadenosine. The mean fertilization rate per patient was 33.1% in the treatment group compared with 37.0% in the control group. The mean cleavage rate per patient was 79.6% for treatment versus 68.7% for control embryos. No differences in embryo quality were noted. The results of this study demonstrate that an indiscriminate use of pentoxifylline and 2-deoxyadenosine is not beneficial to fertilization in couples with previous IVF failure. Further prospective research may be needed to assess the benefit of pentoxifylline and 2-deoxyadenosine in patients selected by preliminary functional in vitro tests.

Treatment of male infertility and idiopathic failure to fertilize in vitro with under zona insemination and direct egg injection

Objective: Failure to fertilize eggs in vitro may be countered by micromanipulation of gametes to place selected spermatozoa underneath the zona pellucida of the egg or directly into the egg, thereby improving chances of fertilization and production of viable embryos. Analysis of our clinical data for assisted fertilization was undertaken to assess those factors of relevance in this therapy, and a description of our procedures are given. Study Design: Retrospective analysis of 85 cycles (73 couples) of in vitro fertilization and embryo transfer performed at a private infertility clinic, in which micromanipulation for assisted fertilization was used to overcome either severe male factor infertility or idiopathic failure to fertilize, was performed. Results: In 60 cycles where only embryos from under zona insemination were available for uterine transfer, 15 singleton and two twin pregnancies occurred (28.3% viable pregnancy rate per transfer, 14.1% embryonic implantation). In 14 of these cycles embryos arose only after repeated under zona insemination adding more spermatozoa; this accounted for four of the singleton and one of the twin pregnancies (38.5% pregnancy rate, 22.2% embryonic implantation). No embryos arose from partial zona dissection performed in five cycles on sibling eggs. However, in 16 cycles conventional insemination yielded fertilization in six cycles, and mixed transfer of these embryos and sibling embryos from under zona insemination gave rise to one pregnancy from four transfers (pregnancy rate 25%, embryonic implantation 7.1%). Likewise, in nine cycles donor spermatozoa yielded fertilization in eight cycles, and mixed transfer with sibling embryos fertilized by under zona insemination with partner's spermatozoa gave rise to two pregnancies from five transfers (pregnancy rate 40%, embryonic implantation 15.8%). Fertilization and pregnancy rates did not differ whether couples suffered either from male factor infertility or from previous idiopathic fertilization failure. Direct egg injection of a single spermatozoon into 105 eggs gave an 88.6% egg survival and 32.3% fertilization. Mixed transfers with sibling embryos from conventional and under zona insemination yielded one triplet, one twin, and three singleton pregnancies. Conclusions: Overall, a 24.7% (21/85) viable pregnancy rate per cycle initiated occurred when only embryos from assisted fertilization were available. This strongly indicates that assisted fertilization made a real contribution in cases where either insufficient spermatozoa were available for conventional insemination or in cases where previous fertilization failure had arisen. The wide range of seminal parameters were found to be unhelpful in defining chances of success with assisted fertilization.

Treatment of male infertility and idiopathic failure to fertilize in vitro with under zona insemination and direct egg injection

Failure to fertilize eggs in vitro may be countered by micromanipulation of gametes to place selected spermatozoa underneath the zona pellucida of the egg or directly into the egg, thereby improving chances of fertilization and production of viable embryos. Analysis of our clinical data for assisted fertilization was undertaken to assess those factors of relevance in this therapy, and a description of our procedures are given. Retrospective analysis of 85 cycles (73 couples) of in vitro fertilization and embryo transfer performed at a private infertility clinic, in which micromanipulation for assisted fertilization was used to overcome either severe male factor infertility or idiopathic failure to fertilize, was performed. In 60 cycles where only embryos from under zona insemination were available for uterine transfer, 15 singleton and two twin pregnancies occurred (28.3% viable pregnancy rate per transfer, 14.1% embryonic implantation). In 14 of these cycles embryos arose only after repeated under zona insemination adding more spermatozoa; this accounted for four of the singleton and one of the twin pregnancies (38.5% pregnancy rate, 22.2% embryonic implantation). No embryos arose from partial zona dissection performed in five cycles on sibling eggs. However, in 16 cycles conventional insemination yielded fertilization in six cycles, and mixed transfer of these embryos and sibling embryos from under zona insemination gave rise to one pregnancy from four transfers (pregnancy rate 25%, embryonic implantation 7.1%). Likewise, in nine cycles donor spermatozoa yielded fertilization in eight cycles, and mixed transfer with sibling embryos fertilized by under zona insemination with partner's spermatozoa gave rise to two pregnancies from five transfers (pregnancy rate 40%, embryonic implantation 15.8%). Fertilization and pregnancy rates did not differ whether couples suffered either from male factor infertility or from previous idiopathic fertilization failure. Direct egg injection of a single spermatozoon into 105 eggs gave an 88.6% egg survival and 32.3% fertilization. Mixed transfers with sibling embryos from conventional and under zona insemination yielded one triplet, one twin, and three singleton pregnancies. Overall, a 24.7% (21/85) viable pregnancy rate per cycle initiated occurred when only embryos from assisted fertilization were available. This strongly indicates that assisted fertilization made a real contribution in cases where either insufficient spermatozoa were available for conventional insemination or in cases where previous fertilization failure had arisen. The wide range of seminal parameters were found to be unhelpful in defining chances of success with assisted fertilization.

Pentoxifylline is not useful in enhancing sperm function in cases with previous in vitro fertilization failure

To assess the efficiency of the addition of pentoxifylline to spermatozoa for in vitro fertilization (IVF) in cases with previous fertilization failure. After retrieval, oocytes were divided at random and inseminated with spermatozoa prepared with or without pentoxifylline. In vitro fertilization program of the Centre for Reproductive Medicine of the Dutch-speaking Brussels Free University, Belgium, a tertiary referral institution. Couples in this study were undergoing a second or third IVF attempt for the treatment of male factor infertility. Sperm samples were divided into two equal parts. The first part was prepared with 3.6 mM pentoxifylline (treatment group) and the other part without pentoxifylline (control group). After swim-up, oocytes were randomly inseminated with spermatozoa from either treatment. Fertilization and cleavage rates after IVF. Overall a fertilization rate of 8.8% was achieved with no significant differences between treatment and control groups. Cleavage rate was 81.5% and was not different between groups. This study demonstrates no therapeutic advantage of using pentoxifylline in IVF for male factor infertility in cases with previous fertilization failure.

Successful use of the sperm motility enhancer 2-deoxyadenosine in previously failed human in vitro fertilization

The outcome of in vitro fertilization treatment in male-factor infertility is generally poor, due mainly to poor fertilization rate and hence fewer available embryos for replacement. This study was carried out to assess the value of asthenospermic sperm exposure to a motility enhancing agent, 2-deoxyadenosine (2-DXA), on our in vitro fertilization program in couples undergoing repeat treatment after previous failed fertilization. Following sperm wash and incubation in 2-DXA-supplemented medium, marked significant improvements were observed in the sperm motility pattern and the number of recoverable sperms as compared to control unexposed samples. There was also a significantly better fertilization rate and higher number of replaceable embryos available following sperm wash in 2-DXA as compared to those washed without it. Following embryo transfer, pregnancy rate was comparable to the generally reported pregnancy rates for routine in vitro fertilization and embryo transfer treatment. Three normal babies were born. Our results indicate that 2-DXA enhances fertilization rate in some asthenospermic patients and that it has no adverse effect on embryonic development.

Assisted reproductive technology

Several aspects of reproductive technology are discussed. In tubal infertility, the choice between surgery or in vitro fertilization and embryo transfer (IVF-ET) is addressed. In cases with bilateral distal occlusion or otherwise bad prognosis, IVF is probably more successful and less expensive. IVF in unstimulated cycles has given promising results, with pregnancy rates comparable to the results from the National IVF-ET Registry. If these results can be confirmed by more studies they will probably have a great impact on the choice of treatment in tubal infertility. The results obtained with various transfer procedures in nontubal infertility have still to prove tubal transfer to be a more effective procedure than IVF. Finally, studies on microinsemination in male infertility or unexplained infertility with previous fertilization failure in IVF show promising results with the subzonal insemination and partial zona dissection procedures.

Transfer of human sperm into the perivitelline space of human oocytes after zona-drilling or zona-puncture

To evaluate the transfer of sperm from severely oligozoospermic men into the perivitelline space of mature oocytes, zona-drilling with acid phosphate-buffered saline (PBS) and direct zona-puncture in the presence of cytochalasin D were studied. Zona-drilling also was done for eggs from patients with previous failed in vitro fertilization (IVF). Forty-seven eggs from seven patients with oligozoospermia and three patients with failed IVF had a mean of between 2.6 and 3.6 sperm transferred into the perivitelline space. In the group whose eggs had zona-drilling with acid PBS, 1 of 13 eggs fertilized from the oligozoospermic category, while there was no fertilization from the failed IVF category. Karyotyping of the unfertilized eggs after zona-drilling revealed a high incidence (2/5 and 3/7, respectively) of possible arrest at anaphase II after reinitiation of meiosis. In the group whose eggs were directly punctured through the zona in the presence of cytochalasin D, there was no fertilization in 23 undamaged eggs. Two of the 15 interpretable karyotypes were aneuploid, but this incidence is within that observed for our unfertilized eggs after IVF. Hence, the use of acid PBS for zona-drilling is not advised. Moreover, transfer of sperm from men with previous failed fertilization resulted in poor fertilization rates.

A prospective study of prognostic factors in in vitro fertilization and embryo transfer

Multiple factors influence the outcome of in vitro fertilization and embryo transfer (IVF-ET). This prospective study was designed to assess their relative importance, in order to improve prognostic ability and treatment success. Prior to IVF-ET, couples were divided into "good" (GP) and "poor" (PP) prognosis groups according to female age, semen quality, previous response to stimulation, and embryo quality. The data obtained from 716 consecutive treatment cycles then were evaluated using univariate statistics and logistic regression, a technique designed to assess the relative contribution of significant factors. The pregnancy rate per GP cycle was 14.7%, compared with 5.4% per PP cycle (chi 1(2) = 12.7, P less than 0.001). The most important prognostic factors were female age, the pregnancy rate showing a linear decline after the age of 25, and previous failed fertilization due to abnormal sperm. The rate of pregnancy also declined after 14 or more follicles were aspirated and/or nine oocytes were retrieved. A formula for the probability of pregnancy, derived from the logistic regression, provides patients with a more accurate prognosis before treatment.