Can severe male factor infertility be treated without micromanipulation?**Presented at the 41st Annual Meeting of the Pacific Coast Fertility Society, Indian Wells, California, April 14 to 18, 1993

Intracytoplasmic sperm injection is not superior to conventional IVF in couples with non-male factor infertility and preimplantation genetic testing for aneuploidies (PGT-A)

STUDY QUESTION

Does the insemination method impact the euploidy outcome in couples with non-male factor infertility?

SUMMARY ANSWER

Conventional IVF can be applied in cycles with preimplantation genetic testing for aneuploidies (PGT-A), as both IVF and ICSI generate equal numbers of euploid blastocysts.

WHAT IS KNOWN ALREADY

Ever since its introduction, the popularity of ICSI has increased tremendously, even in couples with non-male factor infertility. The use of conventional IVF is a contraindication for couples undergoing PGT to ensure monospermic fertilisation and to eliminate potential paternal contamination from extraneous sperm attached to the zona pellucida. Despite this, it has recently been shown that sperm DNA fails to amplify under the conditions used for trophectoderm biopsy samples.

STUDY DESIGN, SIZE, DURATION

This single-centre prospective pilot study included 30 couples between November 2018 and April 2019.

PARTICIPANTS/MATERIALS, SETTING, METHOD

Arab couples, with a female age between 18-40 years, body mass index ≤30 kg/m2, at least 10 cumulus oocyte complexes (COCs) following oocyte retrieval (OR) and normal semen concentration and motility (WHO) in the fresh ejaculate on the day of OR, were eligible for the study. Half of the sibling oocytes were assigned to conventional IVF, and the other half were assigned to ICSI. All embryos were cultured in a time-lapse imaging system in Global Total LP media. Blastocysts were subjected to trophectoderm biopsy on Day 5, 6 or 7 and next-generation sequencing (NGS) to determine blastocyst ploidy status. The primary objective was to determine the euploid rate in blastocysts from sibling oocytes.

MAIN RESULTS AND THE ROLE OF CHANCE

A total of 568 COCs were randomly allocated between IVF (n = 283; 9.4 ± 4.0) and ICSI (n = 285; 9.5 ± 4.1). While the incidence of normal fertilisation per cycle (6.1 ± 3.8 (64.0%) vs 6.3 ± 3.5 (65.4%); P = 0.609) was distributed equally between IVF and ICSI, the degeneration rate (0.1 ± 0.3 vs 0.7 ± 0.8; P = 0.0003) was significantly higher after ICSI and the incidence of abnormal fertilisation (≥3 pronuclei) was significantly higher after IVF (0.9 ± 1.2 vs 0.2 ± 0.4; P = 0.005). For all fertilised oocytes, there were no differences in the number of good-quality embryos on Day 3 (74% vs 78%; P = 0.467), nor in the blastulation rate on Day 5 (80.4% vs 70.8%; P = 0.076). The total number of blastocysts biopsied per cycle on Days 5, 6 and 7 was not significantly different between IVF or ICSI (4.0 ± 2.8 vs 3.9 ± 2.5; P = 0.774). With euploid rates of 49.8 and 44.1% (P = 0.755; OR: 1.05664 [0.75188-1.48494), respectively, there was no significant difference identified between IVF and ICSI (2.0 ± 1.8 vs 1.9 ± 1.7; P = 0.808) and all couples had at least one euploid blastocyst available for transfer. When considering only euploid blastocysts, the male/female ratio was 61/39 in IVF and 43/57 in ICSI (P = 0.063).

LIMITATIONS, REASON FOR CAUTION

This is a pilot study with a limited patient population of 30 couples (and 568 COCs) with a normal ovarian response. The results of our study should not be extrapolated to other patient populations.

WIDER IMPLICATIONS OF THE FINDINGS

It is safe to apply conventional IVF in couples with non-male factor infertility undergoing PGT-A.

STUDY FUNDING/COMPETING INTEREST(S)

No funding was obtained. There are no competing interests.

TRIAL REGISTRATION NUMBER

NCT03708991.

[A prospective auto-controlled study to evaluate the interest of selected sperm morphology to inseminate oocytes during IVF]

OBJECTIVES

Since we observed in our laboratory a significant decrease of the fertilization rate in the classical IVF procedure compared to ICSI, we wanted to evaluate a new insemination procedure, using sperm morphology of selected semen as a criterion taken into account to calculate the number of mobile sperm to inseminate.

PATIENTS AND METHODS

Therefore, we designed a prospective autocontrolled study which took place from September 2006 to May 2007. All IVF attempts resulting from infertile couples were included in the study if a previous analysis (lesser than one year) of sperm parameters performed in our laboratory was assessed as normal. The retrieved oocytes were separated into two groups (sibling ovocytes), inseminated randomly either with the usual procedure (control group) or with the tested protocol (tested group). Fertilization rate was the primary end point to evaluate this assay. Polyspermy rates were also compared. Subsequently, embryonic quality and development were assessed to eliminate an oxidative stress impact. Paired Student t-test was applied for statistical analysis.

RESULTS

In all, 130 couples were included. The diploid fertilization rate was significantly increased in the tested group compared to the control group (66.9% vs 61.3%; p=0.017). No statistically significant difference was showed between the polyspermy rate and numbers of (i) good quality embryos and (ii) blastomeres per embryo into the two groups.

DISCUSSION AND CONCLUSION

Compared with the conventional insemination procedure, the fertilization rate benefited from the tested insemination method in our laboratory without damaging embryonic growth. In the limit of our procedure, selected sperm morphology should be used to inseminate an appropriate number of spermatozoa within oocytes, even in case of normal semen values.

Low total normal motile count values are associated with increased sperm disomy and diploidy rates in infertile patients

This study was undertaken to evaluate the possibility of identifying men at increased risk of sperm aneuploidy and diploidy on the bases of specific cut-off values of the total normal motile count (TNMC). Twenty-seven consecutive, unselected male patients referred to our Unit were studied: 11 patients with normal sperm parameters (group A) suffering from unexplained infertility and 16 infertile patients with abnormal sperm parameters (group B). Disomy rates for chromosomes 1, 4, 8, 12, 18, X and Y were ascertained for each patient by means of triple and double fluorescence in situ hybridization (FISH) experiments. Both univariate and multivariate statistical analyses by principal component analysis (PCA) were performed for comparisons between sperm aneuploidy rates and semen quality (TNMC). TNMC scores in the two groups were significantly different (23.5 x 10(6) and 1.52 x 10(6), in groups A and B, respectively, p = 0.00002). In general, higher sperm disomy rates were noted for all chromosomes in group B compared with group A. Statistical significance was observed for disomy 1, total disomy rate (3.36% vs. 1.38%), and diploidy (0.49% vs. 0.19%) (p < 0.01). For disomy 4 and 8, differences resulted close to significance. PCA clearly showed how independent variables were inter-related. Infertile men with TNMC < 2 x 10(6) (male factor) were found to be at increased risk for sperm aneuploidy and diploidy. Multivariate analysis by PCA resulted as a useful method to visualize the information of the data sets on a bi-dimensional plot considering all the patients and all the variables at the same time.

Morphology of spermatozoa used in IVF and ICSI from oligozoospermic men

The purpose of this study was to determine morphology in human spermatozoa from men with oligozoospermia and correlate with the fertilization rate, embryo score and pregnancy rate after IVF and intracytoplasmic sperm injection (ICSI) respectively. The study group consisted of 125 couples where the male partner suffered from oligozoospermia. Fifty of these had IVF (group A). Seventy-five couples in whom ICSI had been performed made up group B. Sperm samples were assessed according to the WHO manual. For each male, morphology of spermatozoa was judged according to Krüger's strict criteria, WHO criteria and the teratozoospermia index (TZI). Oocyte monitoring was carried out according to a long down-regulation protocol using gonadotrophin-releasing hormone, recombinant FSH and human chorionic gonadotrophin. Embryos were transferred on day 2 after fertilization, with a maximum of three embryos. This study demonstrated no correlation between any of the morphological assessments of spermatozoa and the fertilization rate, embryo score and pregnancy rate, either after IVF or ICSI. Morphology in human spermatozoa according to Krüger's strict criteria, WHO criteria and the TZI had no predictive value for the outcome after either IVF or ICSI.

Intracytoplasmic sperm injection versus in vitro fertilization: a randomized controlled trial and a meta-analysis of the literature

OBJECTIVE

To compare ICSI with IVF using two insemination concentrations in moderate male infertility and to compare these data with other randomized controlled trials (RCTs).

DESIGN

Prospective, randomized, controlled trial and meta-analysis.

SETTING

University-based tertiary referral center.

PATIENT(S)

Seventy-three couples undergoing ART.

INTERVENTION(S)

In one IVF group a standard insemination concentration of 0.2 x 10(6)/mL was used, whereas in the other group a high insemination concentration (HIC) of 0.8 x 10(6)/mL was used. Each protocol was compared with ICSI on sibling oocytes.

MAIN OUTCOME MEASURE(S)

Fertilization, fertilization failure, and embryonic development.

RESULT(S)

The overall fertilization rate was significantly lower after standard IVF than after ICSI: 37.4% vs. 64.3%. Where HIC IVF was used, the overall fertilization rate was not significantly different from that after ICSI: 59.6% vs. 67.6%. Eight randomized controlled trials were selected and reviewed together with the present randomized controlled trial by meta-analysis. The risk ratio for an oocyte to become fertilized was 1.9 (95% confidence interval of 1.4 to 2.5) in favor of ICSI, and 3.1 ICSI cycles may be needed to avoid one complete fertilization failure after conventional IVF (95% CI of 1.7 to 12.4).

CONCLUSION(S)

The data from this study and the meta-analysis show that ICSI is a more efficient technique in terms of fertilization, but not in comparison with HIC IVF.

Reevaluation of the clinical importance of evaluating sperm morphology using strict criteria

Several studies suggest that sperm with < or =4% normal morphology (NM) using strict criteria are subfertile and IVF with ICSI may be needed. However, not all studies agree on the clinical importance of the use of NM with strict criteria. One study of males with oligozoospermia found a lower pregnancy rate (PR) following intercourse with sperm with NM > 14% compared to specimen with < or = 4%. The study presented herein evaluated the efficacy of intrauterine insemination (IUI) according to NM using strict criteria. The clinical PRs for first IUI cycles were 30% (28/91 ) for 0-4% normal forms, 26% (71/268) for range of 5-14%, and 20% (11/53) for >14%. This study corroborates previous data with intercourse only, suggesting that sperm with NM < or =4%, using strict criteria are not necessarily associated with lower fecundity.

Controlled comparison of conventional in-vitro fertilization and intracytoplasmic sperm injection in patients with asthenozoospermia

A controlled comparison between conventional in-vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI) has been carried out for patients with </=5% rapid progressive (type A) spermatozoa in their fresh semen. Twenty couples were allocated to the study. All semen samples fulfilled the minimum criteria to be allocated to the conventional IVF programme. The two pronuclear (2PN) fertilization rate per retrieved cumulus-oocyte complex was significantly higher after ICSI (63.4%) than after conventional IVF (22.9%), with complete fertilization failure after IVF in 10 out of the 20 cycles. Embryo quality was similar for both treatments. Sixteen patients received only ICSI embryos, two patients only IVF embryos and two patients received IVF and ICSI embryos. The ongoing clinical pregnancy rate was 45%, the implantation rate was 37%. Comparison of the characteristics of patients/cycles with and without 2PN fertilization revealed a higher proportion of progressively motile spermatozoa in the prepared sperm fraction for the group of patients with fertilization after conventional IVF. It can be concluded from this study that absence of or an extremely low proportion of rapid progressive motility in fresh semen indicates a high risk of complete fertilization failure with conventional IVF.

Numerical dose-compensated in vitro fertilization inseminations yield high fertilization and pregnancy rates

OBJECTIVE

To evaluate in cases with morphologically abnormal sperm whether fertilization and pregnancy rates are increased by normalizing the number of sperm inseminated and whether biomarkers can identify cases of reduced or failed fertilization.

DESIGN

Prospective studies of sperm morphology and function.

SETTING

University hospital assisted human reproduction program.

PATIENT(S)

Partners of 308 women undergoing IVF.

INTERVENTION(S)

Motile sperm populations were assessed for sperm head morphology, for surface receptors for mannose and progesterone binding, and the ability to undergo a free mannose-induced acrosome reaction. Zinc in seminal plasma was determined by atomic absorption spectroscopy.

MAIN OUTCOME MEASURE(S)

Sperm morphology was associated with fertilization and clinical pregnancy rates. Biomarker analyses were correlated with fertilization rates using Kruskal-Wallis tests, chi2 tests, and Spearman rank order correlations.

RESULT(S)

Fertilization and pregnancy rates after numerical dose compensation inseminations were indistinguishable between men with differing percentages of normal sperm. Biomarker deficits were identified irrespective of sperm head morphology in 96% of cases of reduced or failed fertilization.

CONCLUSION(S)

Fertilization and pregnancy rates in cases of abnormal morphology are optimized by inseminating at least 25,000 sperm/mL with normal acrosomes. Reduced or failed fertilization can be predicted by testing for molecular deficits in mannose receptor expression and mannose-stimulated acrosome loss.

Relationship between etiological factors and total motile sperm count in 350 infertile patients

The prevalence of different etiologic factors has been evaluated in 350 male patients consulting the same physician in an urban, ambulatory setting for primary or secondary infertility of more than 1 year. Environmental factors such as alcohol or drugs represented 12% of the etiologies, acquired diseases such as varicocele and prostatitis 40%, congenital diseases and primary testicular failure 16.2%, idiopathic cases 19.4%, and abnormality of sperm transport 7.4%. The severity of sperm alterations in the different etiologic categories was evaluated by the total motile sperm count per ejaculate (TMS) (normal > 16). The TMS was less than 5 in classical causes of male infertility such as testicular failure, endocrinopathy, cancer, or antisperm antibodies. It was more than 10 in controversial causes of infertility such as varicocele, prostatis, chlamydial infections, and professional exposure to heat. After treatment, there was a nonsignificant increase of the TMS in the latter cases. In cases of azoospermia of pituitary origin, the TMS was normalized by a hormonal treatment. In some cases of azoospermia of possible obstructive origin, sperm appeared in the ejaculate after diclofenac treatment. The utility of andrological investigation and treatment is discussed.

The value of motile density, strict morphology, and the hypoosmotic swelling test in in vitro fertilization-embryo transfer

This study was conducted to evaluate the effect of a single abnormal semen parameter on subsequent implantation and pregnancy rates (PRs) following in vitro fertilization-embryo transfer (IVF-ET). The parameters evaluated were motile density (MD), strict normal morphology (SNM), and the hypoosmotic swelling (HOS) test. A total of 592 IVF cycles were evaluated. Patients were divided into four groups each with one abnormal semen parameter except for the control: group 1 (n = 509), control group: MD > or = 10 x 10(6)/mL, HOS > or = 50%, SNM > or = 4%; group 2 (n = 51): HOS and SNM normal, MD < 10 x 10(6)/mL; group 3 (n = 14): MD and SNM normal, HOS < 50%; group 4 (n = 18): MD and HOS normal, SNM < 4%. The implantation rate was 10.2% for the control group. The implantation rate was similar for the low MD (9.0%) and the low SNM (16.7%) groups. However, the low HOS group had a significantly lower implantation rate (0%). The clinical PRs are similar in the control group and low MD and SNM groups, but decreased in the low HOS group (21.5, 15.0, 30.8, and 0%, respectively). Ongoing PRs were also similar with the exception of the low HOS group (0%). This comparative study supports previous conclusions that the subnormal HOS test is the best semen parameter available that predicts poor PRs. It also suggests that some qualitative defect in the embryos may result from defective sperm membranes, resulting in an apparently normal appearance but physiologically defective embryo.

Validation of a scoring method predicting the in-vitro fertilizing ability of human spermatozoa

The fertilizing ability of human spermatozoa depends upon numerous functions such as motility, normal morphology, ability to bind to the zona pellucida and to undergo the acrosome reaction. Hence a lot of tests have been developed to try and predict IVF results. In a previous study we had established a scoring method, based on parameters such as sperm morphology, vitality, motility and the acrosome reaction, which was able to predict up to 83% of in-vitro fertilization results. The present study aimed to validate this score on a separate set of sperm samples. The results confirmed those of the first series. The score allowed prediction of fertilization failures with a 56% sensitivity, a 91% specificity, a 56% positive predictive value and a 91% negative predictive value. Therefore, this score could be used routinely to choose between conventional IVF and ICSI.

Intracytoplasmic sperm injection facilitates fertilization even in the most severe forms of male infertility: pregnancy outcome correlates with maternal age and number of eggs available

OBJECTIVE

To evaluate, in a prospective study, the fertilization and pregnancy rates after intracytoplasmic sperm injection (ICSI) in infertile couples with severe male infertility.

DESIGN

Intracytoplasmic sperm injection was performed in 229 consecutive IVF cycles on 190 couples with rigorously defined severe male infertility or proven failure of fertilization in prior IVF cycles. Neither male nor female partners were chosen from a waiting list or on any other selective basis, including age, prior or anticipated ovarian response, or oocyte number or quality. There were no upper age limits, in no instance was donor sperm used for ICSI, and cycle cancellation rate was minimal.

SETTING

Private genetics and fertility center in Fairfax, Virginia.

MAIN OUTCOME MEASURES

Fertilization, transfer, and pregnancy rates were measured in ICSI-treated couples, and comparisons were made regarding both female age and strictly defined semen categories.

RESULTS

Two hundred six cycles (90%) resulted in ETs, with initiation of 52 pregnancies (25% per transfer, 23% per cycle). Thirty-eight of 52 (18% per transfer) were clinical pregnancies with established gestational sacs or were ongoing or delivered. Pregnancies were achieved even in older women but were more readily established in younger women producing larger numbers of metaphase II oocytes. The severity of semen abnormalities had some small effect on fertilization rate, but only actual necrospermia was associated with markedly decreased frequency of embryo formation. Pregnancy per transfer was similar across groups. In some cases, pregnancy was initiated with fewer than 100 viable sperm in the ejaculate.

CONCLUSIONS

Intracytoplasmic sperm injection is a very powerful new treatment for severe male infertility. Paradoxically, egg number and probably egg quality are now the main determinants of success in treating male infertility.

Sperm stimulants can improve fertilization rates in male-factor cases undergoing IVF to the same extent as micromanipulation by partial zona dissection (PZD) or subzonal sperm insemination (SUZI): a randomized controlled study

PURPOSE

Our purpose was to evaluate the efficacy of direct insemination (IVF), micromanipulation by partial zona dissection (PZD), and subzonal sperm insemination (SUZI) using sperm-treated with pentoxifylline (PF) +/- 2-deoxyadenosine (2DA).

RESULTS

The overall fertilization rate achieved was similar for all three fertilization techniques (33.1, 30.2, and 26.9% for IVF, SUZI, and PZD, respectively). Patients who had reduced fertilization in previous IVF attempts showed improved fertilization with sperm stimulants, either PF alone or PF in combination with 2DA in standard IVF. In certain cases, SUZI or PZD gave significantly improved fertilization rates in comparison to IVF.

CONCLUSION

Selective use of sperm stimulants in IVF can achieve fertilization for the majority of male-factor cases. However, PZD and SUZI techniques are useful, especially when sperm stimulants fail to achieve fertilization or achieve poor fertilization in direct insemination.

In vitro fertilization outcome in the presence of severe male factor infertility

OBJECTIVE

To assess the outcome of standard IVF treatment (nonmicromanipulated) with respect to total motile sperm number recovered by swim-up, particularly for couples with severe male factor infertility defined as total motile sperm number < 0.5 x 10(6).

DESIGN

Retrospective study of patients who underwent successful oocyte retrieval in an IVF program from August 10, 1992 to December 31, 1993.

SETTING

A university-based tertiary referral center (The Toronto Hospital).

PATIENTS

All cycles (n = 672) were divided into four groups according to total motile sperm number recovered using standard swim-up: group 1, total motile sperm number < or = 0.50 x 10(6); group 2, total motile sperm number between 0.51 and 1.00 x 10(6); group 3, total motile sperm number between 1.01 and 1.50 x 10(6); and group 4, total motile sperm number > or = 1.51 x 10(6). All patients received the same controlled ovarian hyperstimulation protocol, which consisted of a GnRH analog flare-up followed by parenteral menotropins. Clinical and cycle characteristics in the four groups were analyzed and outcome was evaluated.

RESULTS

There was no significant difference in clinical and cycle characteristics between the groups. The uniformity of the groups justified analysis of their outcome. A fertilization rate of 21.5% was achieved in couples with severe male factor (group 1). Fertilization rate and number of embryos transferred increased directly with the total motile sperm number. There was no significant difference in implantation rate per embryo between the groups.

CONCLUSIONS

The results in couples with severe male factor infertility compare favorably with monospermic fertilization rates reported in the literature using partial zona dissection and subzonal insertion but is lower than with intracytoplasmic sperm injection. Therefore, we believe that couples with severe male factor infertility should be considered for standard IVF, as long as adequate total motile sperm can be recovered (100 x 10(3) per dish). If intracytoplasmic sperm injection is available, it should be offered to these couples.

Using ejaculated, fresh, and frozen-thawed epididymal and testicular spermatozoa gives rise to comparable results after intracytoplasmic sperm injection

OBJECTIVE

To describe the preparation of fresh or frozen-thawed epididymal and testicular sperm for intracytoplasmic single sperm injection and to compare the fertilization, embryo quality, and pregnancy rates (PRs) obtained after using these spermatozoa to the results when freshly ejaculated sperm was used for microinjection.

DESIGN

Retrospective analysis of 1,034 consecutive microinjection cycles. Ejaculated (965 cycles), fresh epididymal (43 cycles), frozen-thawed epididymal (9 cycles), and testicular sperm (17 cycles) was used for intracytoplasmic sperm injection.

SETTING

Procedures were performed in a tertiary IVF center coupled with an institutional research environment.

MAIN OUTCOME MEASURES

Semen density and motility were judged by the World Health Organization criteria and sperm morphology was evaluated by the Tygerberg's strict criteria. After microinjection, oocyte intactness, fertilization, embryo cleavage, transfer, and PRs were evaluated and compared.

RESULTS

The median values of total sperm count, total motility and normal morphology were 17.85 x 10(6), 37%, 8% for freshly ejaculated sperm; 46.20 x 10(6), 12%, 9% for fresh epididymal sperm; 0.15 x 10(6), 0%, 0% for frozen-thawed epididymal sperm; and 0.54 x 10(6), 0% for testicular sperm (morphology was not determined). The percentage of intact oocytes after microinjection ranged from 84% to 90%. Normal fertilization rates were high when fresh or frozen-thawed epididymal and testicular spermatozoa were used for the injection (56%, 56%, 48%, respectively) but were significantly lower than for ejaculated sperm (70%). There was a higher proportion of transferable embryos obtained after ejaculated sperm injection than after testicular sperm injection. Forty percent, 58%, 33%, and 46% of cycles had positive serum hCG using ejaculated, fresh, or frozen-thawed epididymal and testicular sperm. Initial pregnancy loss occurred in 26.3% of the conception cycles.

CONCLUSION

Intracytoplasmic sperm injection can provide high normal fertilization, cleavage, and PRs when fresh or frozen-thawed epididymal and testicular spermatozoa are used, but normal fertilization rates are significantly lower than after microinjection with ejaculated sperm.

Cumulus removal and addition of follicular fluid possibly improves pregnancy rates with in vitro fertilization for male factor

This study evaluated the use of in vitro fertilization (IVF) for patients with subnormal semen parameters without the use of micromanipulation. All patients were characterized as having male factor as follows: normal morphology (NM) < or = 10% according to strict criteria [15] and motile density (MD) < or = 10 x 10(6)/mL. Strict morphology was divided into three groups: group I (n = 72), < or = 2% group II (n = 24), 3-5%; and group III (n = 29), 6-10%. Modification of standard IVF techniques included manual cumulus removal (CR) from oocytes, pooling up to ten oocytes together in 1 mL of media, and supplementing media with 20% human follicular fluid (FF). Rates of fertilization and pregnancy were compared. The overall fertilization rate (FR) was 57.7% and the pregnancy rate (PR) per retrieval cycle was 14.8%. There was no significant improvement in the fertilization or PRs when IVF was modified using CR and FF, although the FR was higher in group I for patients who received the modified procedures. In patients with < or = 5 x 10(6) sperm/mL, there were no pregnancies in five cycles and four transfers following the conventional method, but two sets of twins with the modified protocols in seven cycles. Clinical pregnancies were achieved with male factor without the need for micromanipulation. The most severe cases were automatically assigned to modified IVF techniques, e.g., CR with or without FF. Prospective randomized studies are needed to determine if modified procedures are superior to conventional therapy.

Gamete microsurgery for assisted fertilization

Several methods of gamete microsurgery have been proposed to facilitate the union of the spermatozoon and oocyte in infertile couples. Partial zona dissection, subzonal sperm insertion, and intracytoplasmic sperm insertion are the three techniques currently being used for assisted fertilization in human in vitro fertilization laboratories. Fertilization and pregnancy rates after partial zona dissection and subzonal insertion have been variable and rather low. Recent reports of relatively high fertilization and pregnancy rates achieved after intracytoplasmic sperm insertion have rejuvenated interest in gamete microsurgery. Methods for each procedure are described. Studies which have attempted patient selection for gamete microsurgery are discussed.

Development of an effective and simple insemination method for the in vitro fertilization of patients with male-factor infertility

An insemination method involving mechanical removal of the cumulus and multiple oocytes per dish (MRC-MOPD) was applied to achieve in vitro fertilization (IVF) of patients with male-factor infertility, and the prognosis of IVF and embryo transfer was evaluated. Although the fertilization rate of patients with male-factor infertility was only 41.4% (12/29) using standard insemination methods, a 73.0% (27/37) fertilization rate was achieved with the MRC-MOPD method. Moreover, 10 patients with male-factor infertility who were treated with the MRC-COPD method achieved clinical pregnancy. A comparison of the results in the 10 patients who were treated with both methods in common reveals that the MRC-MOPD method also increased the fertilization rate per oocyte. The rate of occurrence of polyploid fertilization did not increase, although large numbers of sperm were inseminated via the MRC-MOPD method. These results indicate that the MRC-MOPD method is an effective and simple insemination technique to achieve successful IVF of patients with male-factor infertility.

Subzonal insemination (SUZI) or in vitro fertilization (IVF) in microdroplets for the treatment of male-factor infertility

PURPOSE

The results of subzonal insemination (SUZI) and in vitro fertilization with microdroplet insemination used in couples with male-factor infertility are presented.

RESULTS

The total fertilization rate was 17.4% for SUZI (n = 89) and 49.3% for microdroplet IVF (n = 100). The fertilization rate for standard IVF (n = 510), not including any male-factor infertility and performed during the same period, was 73.2%. The "take-home baby rate" per started cycle and per embryo transfer (ET), respectively, was 10 and 17.6% for SUZI and 20 and 24.7% for microdrop IVF. For standard IVF these figures were 27 and 31.7%.

CONCLUSION

It was concluded that microdroplet IVF can be used with good results in cases of moderate male-factor infertility. The normal (2PN) fertilization rate with the SUZI technique was only 15.1%. However, despite the low fertilization rate, SUZI should be considered when dealing with severe male-factor infertility.