Semen quality of young men in Switzerland: a nationwide cross-sectional population-based study

BACKGROUND

Sperm counts have been steadily decreasing over the past five decades with regional differences in the Western world. The reasons behind these trends are complex, but numerous insights indicate that environmental and lifestyle factors are important players.

OBJECTIVE

To evaluate semen quality and male reproductive health in Switzerland.

MATERIALS AND METHODS

A nationwide cross-sectional study was conducted on 2523 young men coming from all regions of Switzerland, recruited during military conscription. Semen volume, sperm concentration, motility, and morphology were analyzed. Anatomy of the genital area and testicular volume was recorded. Testicular cancer incidence rates in the general population were retrieved from Swiss regional registries.

RESULTS

Median sperm concentration adjusted for period of sexual abstinence was 48 million/mL. Comparing with the 5th percentile of the WHO reference values for fertile men, 17% of men had sperm concentration below 15 million/mL, 25% had less than 40% motile spermatozoa, and 43% had less than 4% normal forms. Disparities in semen quality among geographic regions, urbanization rates, and linguistic areas were limited. A larger proportion of men with poor semen quality had been exposed in utero to maternal smoking. Furthermore, testicular cancer incidence rates in the Swiss general population increased significantly between 1980 and 2014.

DISCUSSION

For the first time, a systematic sampling among young men has confirmed that semen quality is affected on a national level. The median sperm concentration measured is among the lowest observed in Europe. No specific geographical differences could be identified. Further studies are needed to determine to what extent the fertility of Swiss men is compromised and to evaluate the impact of environmental and lifestyle factors.

CONCLUSION

A significant proportion of Swiss young men display suboptimal semen quality with only 38% having sperm concentration, motility, and morphology values that met WHO semen reference criteria.

Analysis of FOXG1 Is Highly Recommended in Male and Female Patients with Rett Syndrome

We screened a cohort of 5 male and 20 female patients with a Rett spectrum disorder for mutations in the coding region of FOXG1, previously shown to cause the congenital variant of Rett syndrome. Two de novo mutations were identified. The first was a novel missense mutation, p.Ala193Thr (c.577G>A), in a male patient with congenital Rett syndrome, and the second was the p.Glu154GlyfsX301 (c.460dupG) truncating mutation in a female with classical Rett syndrome, a mutation that was previously reported in an independent patient. The overall rate of FOXG1 mutations in our cohort is 8%. Our findings stress the importance of FOXG1 analysis in male patients with Rett syndrome and in female patients when mutations in the MECP2 and CDKL5 genes have been excluded.

Amino acids promote human blastocyst development in vitro

Supplementation of culture media with amino acids has been shown to benefit preimplantation embryo development in several species. This randomized study analysed the in-vitro development of human embryos obtained after IVF in the presence or absence of a combination of amino acids from the 2- to 4-cell stage to the blastocyst stage. A total of 129 human embryos was randomly distributed between three serum-free chemically defined sequential media: (i) glucose-free Earle's balanced salt solution (EBSS) with glutamine (Gln) prior to morula stage, supplemented with glucose for blastocyst formation; (ii) glucose-free EBSS with glutamine and non-essential amino acids (AA) for cleavage stage development, and supplemented with all 20 AA for blastocyst formation (Earle's+AA); and (iii) a sequential commercial medium containing amino acids (K-SCIM). Embryos were individually cultured for successive periods of 24 h. On day 6 of development, blastocysts were differentially labelled and the numbers of trophectoderm and inner cell mass cells, mitoses and dead cells were examined. Blastocyst development was similar for the three sequential media. The mixture of AA significantly increased total blastocyst cell numbers from 61.8 +/- 4.2 with Earle's+Gln to 99.3 +/- 8.4 with Earle's+AA and 100.2 +/- 9.4 with K-SCIM (P = 0.005). This increase was present in both the trophectoderm and inner cell mass lineages (P < 0.02). Furthermore, the dead cell index was significantly lower with Earle's+AA (P = 0.047).

Re-analysis by fluorescence in situ hybridisation of spare embryos cultured until Day 5 after preimplantation genetic diagnosis for a 47, XYY infertile patient demonstrates a high incidence of diploid mosaic embryos: a case report

Mosaicism in 4-8-cell human embryos analysed by fluorescence in situ hybridisation (FISH) has been widely reported, but few studies have addressed the incidence of mosaicism in more advanced embryonic stages. In the present study we analysed spare human embryos in a case of preimplantation genetic diagnosis (PGD) for increased risk of aneuploidy because of an infertile 47,XYY man. After replacement of two embryos typed as 1818XX at PGD, six spare embryos (not frozen because of their low quality) were re-analysed on Day 5 for PGD confirmation. Out of five embryos typed as 1818XY at PGD, four were diploid mosaic (DM) and one was normal in all cells. The sixth embryo, typed as 18XYY/1818181818X at PGD, was a DM. In spite of the bias of our small series of morphologically low-quality embryos, the surprisingly high proportion of mosaics (which confirms previous findings) questions the validity of PGD, but supports the strategy of transferring only the embryos where two blastomeres gave normal and concordant results at PGD. More data are required to understand the clinical significance of early diploid mosaicism (and its impact on implantation rate) and to determine whether some diploid mosaic embryos might be considered safe for transfer.

Increased sperm motility after in-vitro culture of testicular biopsies from obstructive azoospermic patients results in better post-thaw recovery rate

The objective of this study was to optimize the use of testicular biopsies in 14 patients with obstructive azoospermia. Testicular specimens were retrieved from six patients (group I) and cultured at 32 and 37 degrees C for up to 20 days; changes in percentage motile spermatozoa were compared. In four men of group I, one portion of the specimen was frozen at retrieval, and changes in post-thaw motility after 24 h of culture at 37 degrees C were recorded. In the other eight patients (group II), testicular specimens were frozen at retrieval and after 72 h culture at 37 degrees C. Pre and post-freezing motility and post-thaw recovery rate were compared. No significant differences were observed until day 8 in the improvement of motility between 32 and 37 degrees C in-vitro culture. Maximum motility was reached, under both conditions, between 48 h and 72 h. Post-thaw 24 h culture at 37 degrees C of specimens frozen at retrieval did not improve motility; however, 72 h pre-freezing culture significantly improved initial motility (P: < 0.01), post-thaw motility (P: < 0.01) and post-thaw recovery rate (P: < 0. 001). The higher recovery rate of samples frozen 3 days after retrieval allows more economical use of the tissue that is available.

Noninvasive assessment of glucose and pyruvate uptake by human embryos after intracytoplasmic sperm injection and during the formation of pronuclei

OBJECTIVE

To improve in vitro culture conditions and human embryo selection before transfer after IVF with intracytoplasmic sperm injection (ICSI).

DESIGN

A controlled, randomized, prospective study.

SETTING

University hospital-based IVF-ET program.

PATIENT(S)

Couples undergoing ICSI.

INTERVENTION(S)

Culture of human embryos in the presence of 1 mM or 5.56 mM glucose and metabolic measurements with the use of noninvasive microfluorescence assays immediately after ICSI to the time of transfer.

MAIN OUTCOME MEASURE(S)

Embryo development, implantation rate, and glucose and pyruvate uptake.

RESULT(S)

Fertilization rates, early embryo development, and implantation rates were not significantly different between 1 mM and 5.56 mM glucose. Pyruvate uptake was significantly higher during the formation of the pronuclei, at 15 +/- 0.7 and 11.4 +/- 1.3 pmol/embryo/h for fertilized and unfertilized oocytes, respectively. Pyruvate uptake did not correlate with cleavage stage or embryo morphology. However, during the second day of incubation, pyruvate uptake was significantly higher for the untransferred embryos of pregnant women compared with nonpregnant women, at 17.9 +/- 1.5 and 10.8 +/- 1.0 pmol/embryo/h, respectively.

CONCLUSION(S)

The increased level of pyruvate uptake during fertilization reflects the increased demand for energy necessary for the formation of the pronuclei. However, the metabolic measurements could not improve the selection of embryos with the best implantation potential. Finally, the reduction of glucose concentration in the culture medium failed to improve embryo viability.

Comparison of ethylene glycol, 1,2-propanediol and glycerol for cryopreservation of slow-cooled mouse zygotes, 4-cell embryos and blastocysts

The aim of the study was to analyse the toxicity, the osmolar and cryoprotective activity of ethylene glycol (ETG) in terms of survival rate (SR), cleavage rate (CR) and expanded blastocysts percentage (EBP) of mouse embryos. Early mouse embryos and blastocysts were slowly cooled with ETG, 1,2-propanediol (PROH) or glycerol, and thawed. The Van t'Hoff curve for 1.5 mol/l ETG showed recovery of initial volume within 4 min. No differences were observed in CR and EBP of ETG-exposed compared with non-exposed mouse zygotes. The SR of zygotes frozen with PROH was significantly better than with ETG (92% and 60% respectively; P < 0.01), and a significantly better EBP was achieved for blastocysts frozen with glycerol compared with ETG (75% and 50% respectively; P < 0.05). For 4-cell stage embryos, no differences were observed in SR and EBP between ETG and PROH. Higher EBP was observed for 4-cell stage embryos (53%) frozen with ETG compared with pronucleate stage (19%) and blastocysts (48%). Low toxicity, good SR and EBP were observed for mouse embryos frozen with ETG, the best results being obtained at the 4-cell stage. At other embryonic stages, PROH and glycerol respectively seemed to provide better results.

Selection of good embryos for transfer depends on embryo cohort size: implications for the 'mild ovarian stimulation' debate

Embryo quality evaluated by the embryo morphology is a critical parameter in human in-vitro fertilization (IVF) and embryo transfer. It determines which and how many embryos will be replaced, as pregnancy rates are directly related to number and quality of transferred embryos. This retrospective analysis included 1301 IVF and embryo transfer cycles to identify which factors influenced embryo quality. Embryo quality did not correlate with maternal age, causes of infertility, ovarian stimulation parameters or embryo cohort size. However, the mean score of transferred embryos was significantly higher for patients with more than five embryos compared to fewer than five embryos (P < 0.001), irrespective of maternal age. Patients tended to produce a similar embryo quality from cycle to cycle, r = 0.33 (P < 0.001) for the embryo cohort and r= 0.47 (P < 0.001) for the transferred embryos. Poor embryo morphology probably reflects oocytes with compromised development competence and could be an independent factor of infertility. Furthermore, a large embryo cohort was the main factor increasing the chances of at least one good embryo in the cohort.

[Impact of the introduction of intracytoplasmic sperm injection (ICSI) on the treatment of severe male sterility]

The introduction of the Intracytoplasmic Single Sperm Injection (ICSI) has been a turning point for the treatment of severe male infertility. ICSI allowed not only to reduce fertilization failure from 35% to 0.7% but created at the same time the opportunity for a group of patients with extremely low sperm counts to procreate. The discovery that breaking the tail of the spermatozoon prior to the injection was the most important step is at the origin of major improvements: fertilization increased from 22% to 77%, pregnancy rate from 16% to 54% and the implantation rate from 7.4% to 26%. From October 1994 to April 1999, 835 ICSI cycles were performed and resulted in 312 ongoing pregnancies (37%), fertilization rate was 75%, with a fertilization failure of only 0.7%. The use of ICSI and IVF on sibling oocytes for semen samples with doubtful fertilizing ability clearly illustrated the superiority of ICSI. No fertilization failures occurred after ICSI and the fertilization rate was 76% versus 27.8% (P < 0.01). Similar benefit of ICSI was shown for crytozoospermia up to then a hopeless situation. A total of 26 pregnancies were obtained out of 87 cycles with a fertilization rate of 58.8%. Similar results were obtained when ICSI was combined with testicular sperm, 20 pregnancies occurred after from 46 transfers (43%) including cycles with cryopreserved testicular sperm. It is now clear that ICSI is the method of choice for the treatment of severe male infertility.

[In vitro fertilization at the Erasme Hospital: 10 years and 1000 pregnancies later...]

This contribution summarize ten years of in vitro fertilization of clinical work. Activity growth, improvements of results (mean fertilization rate increased from 45% to 58%, fertilization failure dropped from 18% to 7%, pregnancy chances gains 9% to reach 44% per trial) and new treatments possibilities (severe male infertility) thanks to the ICSI technic were the major characteristics of this last ten years. The original anonymous oocyte donation program with donors permutation initiated as soon as 1990 has imposed itself due to it's exceptional efficiency with a pregnancy rate of 95% per oocyte pick up on a population of 46 donors and 145 recipient cycles. Thanks to the large population studied (4028 cycles, 1071 pregnancies), the tendencies in human fecundity (impact of age) and the risks linked to multiples pregnancies could be highlighted, stressing the importance of future developments presented in the other contributions following this general presentation of results.

Effects of taurine on human embryo development in vitro

Glutamine and taurine are reported to be beneficial for mouse embryo development in vitro, and we have recently shown that glutamine improves human blastocyst formation in vitro. This randomized study compared the development of supernumerary human embryos in the presence of 1 mmol/l glutamine and/or 5 mmol/l taurine from the 2-4-cell stage to the blastocyst stage. Blastocyst development and cell numbers were similar in the presence of glutamine or taurine: 52.6% and 58.3% of the embryos reached the blastocyst stage, respectively. Pyruvate uptake was similar in the presence of glutamine or taurine throughout development, as was lactate production after the 8-cell stage. Before this stage, lactate production was 4-fold higher in the presence of taurine (P < 0.001). The proportion of embryos reaching the blastocyst stage was similar with glutamine alone or with glutamine and taurine (62.5% and 47.2% respectively), as were the blastocyst cell numbers (63.0 +/- 4.6 and 61.0 +/- 5.1 respectively). In conclusion, taurine supports development of 2-4-cell human embryos to the blastocyst stage, although it does not further augment the beneficial effects of glutamine.

The outcome of cryopreserved human embryos after intracytoplasmic sperm injection and traditional IVF

OBJECTIVE

Our objective was to analyze the outcome of cryopreserved embryos obtained after intracytoplasmic sperm injection (ICSI) and in vitro fertilization (IVF) in terms of survival rate, implantation rate (IR), total and clinical pregnancy rate (PR) in a retrospective, comparative study.

METHODS

Three hundred seventy-five IVF and 463 ICSI surnumerary cleaved embryos, frozen on Day 2 with 1,2-propanediol, were thawed.

RESULTS

Thirty-two percent of the thawed IVF embryos survived and 11 pregnancies (8 clinical) were obtained from 68 transfers (16.1%). Fourty-seven percent of the ICSI embryos survived, with 19 pregnancies (18 clinical) from 116 transfers (16.4%). The IR was 8.5% (8/94) in IVF cycles and 10.8% (20/185) in ICSI cycles.

CONCLUSIONS

A significantly better survival rate of ICSI embryos was observed but with no difference in PR, preclinical, and clinical abortion rate, or IR.

Randomized autocontrolled comparison of the embryo culture performance of Nunc and Falcon petri dishes

PURPOSE

Our purpose was to compare the embryo culture performance of two types of petri dishes (Nunc and Falcon).

METHODS

Mouse zygotes were cultured up to the expanded blastocyst stage in both types of dishes. The oocytes from 50 in vitro fertilization cycles were randomly divided between the two types of dishes. Fertilization, cleavage, and embryo quality were compared. Oocytes from another 50 cycles were all cultured at random in either type of dish. Pregnancy and implantation rates were compared between the two types.

RESULTS

Of 91 mouse zygotes, 81 cleaved to two-cell-stage embryos, and 64 became expanded blastocysts in Falcon dishes; of 99 zygotes, 81 cleaved to two-cell-stage embryos and 66 became expanded blastocysts in Nunc dishes. Of 248 oocyte-cumulus complexes (OCC), 145 fertilized in Falcon dishes, and of 269 OCC, 175 fertilized in Nunc dishes. The high quality embryo ratio was 51 out of 118 in Falcon dishes, not different from that in Nunc dishes, 58 out of 139. In Falcon dishes 72 out of 118 embryos were at least at the four-cell stage after 45 hr, versus 70 out of 139 in Nunc dishes. Twenty-three clinical pregnancies were obtained in the first 50 cycles with sibling oocytes. In the second group, with randomization of the cycles between Nunc and Falcon, 8 pregnancies were obtained in the Nunc and 10 in the Falcon dishes. The implantation rate in this second group of 50 cycles was 9 out of 61 in Falcon and 11 out of 57 in Nunc dishes.

Comparison of two elective transfer policies of two embryos to reduce multiple pregnancies without impairing pregnancy rates

A first elective transfer policy of two embryos based solely on embryo morphology was compared to a more restrictive policy transferring two embryos to all patients aged < 35 years with less than three previous cycles to reduce the incidence of multiple pregnancies. With a significant reduction in the number of triple transfers from 72.4 to 44.3%, the delivery rates were similar for both policies, 31 and 32.1%. However, the multiple pregnancy rates per transfer significantly decreased from 12.5 to 7.8% (P < 0.05). Of 99 pregnancies, only 24.2% were multiple including 1% of triplets compared to 40.7% multiple pregnancies including 6.7% of triplets for the first policy. Forty-eight transfers of two average embryos with the new policy were compared to 264 transfers of three average embryos with the old policy. Multiple pregnancy rates per transfer were significantly reduced by a third from 23 to 8% (P < 0.05) without a reduction of the pregnancy rates (42 and 48%). This study demonstrated that elective transfer of two embryos reduced the number of multiple pregnancies without impairing the pregnancy rates even with the transfer of average embryos.

A first prospective study of the individual straight line velocity of the spermatozoon and its influences on the fertilization rate after intracytoplasmic sperm injection

The straight line velocity of 500 individual spermatozoa was measured immediately before their direct injection into the cytoplasm of 500 metaphase II oocytes. The straight line velocity (VSL) did not have a normal distribution (P < 0.01) and ranged between 0 and 35 microm/s. The fertilization rate (84%) was significantly (P < 0.008) higher in the quartile of the sperm population with the highest VSL compared to the fertilization rate (68%) in the quartile with the lowest VSL. Embryo cleavage and embryo quality were not different in the quartiles of the sperm population used for injection.

Comparison of pregnancy outcome after intracytoplasmic sperm injection and in-vitro fertilization

The aim of this study was to compare pregnancy characteristics and perinatal outcome of intracytoplasmic sperm injection (ICSI) pregnancies with pregnancies obtained after in-vitro fertilization (IVF). Retrospectively, 145 ICSI pregnancies were matched with 145 IVF pregnancies using the last menstruation data. The main outcome measures were preclinical and clinical abortions, ectopic pregnancies, multiple gestations, prenatal morbidity, prematurity, Caesarean section, birthweight, perinatal mortality and malformations for singletons, twins and triplets. Although patients were significantly younger (P < 0.001) in ICSI (31 years) than in IVF (33 years), their infertility duration (5 years) was similar. The mean number of transferred embryos (2.7 embryos per transfer) was similar in IVF and ICSI. The rates of preclinical (15%) and clinical abortions (11% in ICSI versus 15% in IVF) were not different. Four ectopic pregnancies were observed in the IVF group and none in the ICSI group. In ICSI, two minor malformations were detected and two therapeutic abortions were performed respectively for polymalformations and suspicion of cystic fibrosis. The rate of congenital malformation was 2.8% in ICSI and 2.2% in IVF. In this last group, one therapeutic abortion for malformation of neural tube was performed and two minor malformations were detected. The rate of aborted embryonic sacs before 16 weeks of gestation was not significantly lower in ICSI compared with IVF (13.7% versus 20%). The rate of multiple gestations was similar in both groups (31% in IVF and 35% in ICSI). The number of Caesarean sections was similar in IVF and in ICSI and was twice as frequent for twins versus singletons. The number of singletons born by Caesarean section was 21% after ICSI and 17% after IVF. Mean birthweights and gestational ages at birth for twins were significantly higher (P < 0.05) in ICSI than in IVF (2488 versus 2281 g and 36.5 versus 35.5 weeks). This difference was not observed for singletons. In conclusion, pregnancy characteristics and perinatal outcome after ICSI showed no increase in the number of pathologies in comparison with IVF.

Coagulase and protein A polymorphisms do not contribute to persistence of nasal colonisation by Staphylococcus aureus

The nasal carriage rate of Staphylococcus aureus was examined in a longitudinal study of 31 healthy Danish volunteers. Each person was classified as persistent (>8 positive cultures from 10 examinations), an intermittent carrier (50-80% positive cultures) or an ocassional carrier (positive cultures on 10-40% of ocassions only). One hundred and twenty strains from these persons were subjected to phage typing and random amplification of polymorphic DNA (RAPD) analysis. Phage and RAPD typing were in close agreement. RAPD confirmed the spread of a particular S. aureus clone (phage type 95) throughout Denmark. However, no common genotype or phenotype characteristics of S. aureus that could separate persistent from intermittent or incidental colonisers were identified. The immunoglobulin binding protein A and the prothrombin binding coagulase protein are both putative S. aureus virulence or defence factors. Analysis of polymorphisms in the variable repeat regions in the genes for these proteins showed no correlation between the number of repeat units and, consequently, the protein structure with the ability of strains to persist in the human nasal mucosa. The amount of protein A, detectable by its IgG binding activity, appeared not to be correlated to persistence of carriage. Thus protein A and coagulase gene polymorphisms do not seem to play a significant role in the propensity of S. aureus to colonise human nasal epithelium. Furthermore, based on the genetic heterogeneity encountered among the S. aureus strains it is suggested that within the current study population, no single clonal lineage of S. aureus has increased capability to colonise the human nasal epithelium.

Glass wool column filtration, an advantageous way of preparing semen samples for intracytoplasmic sperm injection: an auto-controlled randomized study

The characteristics of the glass wool filtration technique for the preparation of semen samples in an intracytoplasmic sperm injection programme (ICSI) were compared with a two-layer Percoll density gradient procedure. Half of each of 25 semen samples were prepared by each technique. The oocytes from each patient were randomly injected, half with spermatozoa prepared by glass wool filtration and half with Percoll-separated spermatozoa from the same semen sample. The percentage of recovered motile spermatozoa, the total motile sperm count, the percentage of morphologically normal forms, the fertilization rate, the cleavage rate and embryo quality obtained with both preparations were analysed. The 95% confidence intervals obtained through the Altman-Bland analysis showed that the percentage of motile spermatozoa recovered was 3.5-9.9% higher with the glass wool filtration technique, and this was highly correlated (r = 0.92, P = 0.0001) to the method. Similarly, the total number of spermatozoa available for ICSI was 0.18 x 10(6)-2.44 x 10(6) higher with the glass wool column and was highly correlated to the method (r = 0.956, P = 0.0001). Also, the percentage of normal forms was 1.25-3.31% higher after glass wool filtration but was poorly correlated to the method (r = 0.47, P = 0.017). Out of 100 metaphase II oocytes injected with glass wool-extracted spermatozoa, 77 fertilized and 72 cleaved. Out of 97 metaphase II oocytes injected with Percoll-selected spermatozoa, 71 fertilized and 69 cleaved. These results were not statistically different. The mean +/- SEM embryo quality score for the glass wool group (2.90 +/- 0.27) was the same as that for the Percoll group (2.80 +/- 0.24). No fertilization failures occurred and 11 patients (44% per oocyte retrieval) became pregnant. It was concluded that glass wool filtration for semen preparation in an ICSI programme offers higher sperm recovery and sperm morphology of superior quality than with the classic two-layer Percoll gradient method, without affecting the fertilization rate and embryo quality.

Oocyte shortage for donation may be overcome in a programme with anonymous permutation of related donors

Difficulty in recruiting donors plays a crucial role in oocyte donation programmes. We report here an original strategy to overcome this problem, consisting of sharing out anonymous oocytes between recipients, which has markedly improved treatment efficiency by avoiding freezing or destruction of supernumerary embryos. Each patient received part of the supply of oocytes from several donors in four successive cycles, while each donor underwent oocyte retrieval only once. This strategy led to one pregnancy per treated donor, increased treatment efficacy by 300%, and reduced dramatically the oocyte shortage at our centre. The system avoids wastage of the rare and precious donated oocytes, increases the chance of pregnancy for each related recipient and even permits the inclusion of some recipients without related donors.

Clinical parameters influencing human zona pellucida thickness

OBJECTIVES

To assess which clinical parameters influence human oocyte zona pellucida (ZP) thickness.

PATIENTS

Sixty-five couples undergoing 75 IVF-ET cycles.

MAIN OUTCOME MEASURE

Zona pellucida thickness of 827 oocytes measured 16 to 20 hours after in vitro insemination under inverted light microscope.

RESULTS

Zona pellucida thickness was 18.9 +/- 3.8 microns (mean +/- SD) for unfertilized, 16.4 +/- 3.1 microns for fertilized, and 15.1 +/- 2.4 microns for polyspermic oocytes (significantly different). Among our patients, a few underwent two (or even three) IVF-ET cycles, and the mean ZP thickness was, in most cases, not significantly different from one cycle to the other(s). Regression analyses were calculated between ZP thickness and available clinical parameters, i.e., the age of the women, the duration of stimulation, the cumulus maturity, the number of retrieved oocytes, the number of hMG doses, the maximum E2 level, and the follicular volume. A significant linear decreasing relationship exists between the mean ZP thickness of each patient and the maximum E2 level and an increasing one with the hMG dose. Relationships with the other parameters appeared to be nonsignificant.

CONCLUSION

The ZP thickness is basically an individual feature that influences the fertilization rate. Nevertheless, it may be influenced slightly by the hormonal treatment during stimulation.

Is intracytoplasmic sperm injection (ICSI) a safe procedure? What do we learn from early pregnancy data about ICSI?

The aim of this study was to evaluate the safety of the intracytoplasmic sperm injection (ICSI) procedure by analysing early pregnancy data from ICSI and in-vitro fertilization (IVF) patients. In all, 50 ICSI pregnancies were compared with 226 IVF pregnancies. Comparisons were made during the first 9 weeks after the theoretical last menstrual period (7 weeks after oocyte retrieval) with regard to epidemiological data, plasma hormonal concentrations and transvaginal ultrasonographical findings. Although patients were significantly (P < 0.001) younger in ICSI (31 years) than in IVF pregnancies (33 years), their duration of infertility was similar. Miscarriage and multiple gestation rates were not significantly different in ICSI pregnancies (respectively 24 and 24%) from those found after IVF (32 and 29%). The probability of developmental arrest of the intrauterine sac (miscarriages and vanishing twins) was similar in both ICSI (16%) and IVF (25%) cases. The mean plasma hormonal concentrations starting from day 11 after oocyte retrieval were similar in both groups. Every ICSI and IVF pregnancy showed an embryo with cardiac activity at 7 weeks. Early pregnancy data did not show any abnormal findings for pregnancies achieved using ICSI compared to those achieved by IVF.

The long-acting gonadotropin-releasing hormone analogues impaired the implantation rate

OBJECTIVES

To determine the efficacy and innocuousness of long-acting versus short-acting GnRH analogues (GnRH-a) in long protocol for in IVF-ET.

DESIGN

Prospective randomized study.

SETTING

The IVF unit at an academic hospital.

PATIENTS

One hundred couples admitted for their first IVF-ET attempt.

MAIN OUTCOME MEASURES

Serum concentrations of LH, E2, and P during the all cycles and duration of pituitary desensitization were assessed, as well as fertilization rate, embryo quality, and implantation and pregnancy rates.

RESULTS

Significantly more days (10.8 +/- 1.8 versus 9.2 +/- 1.7 days) of stimulation and more ampules of hMG (47 +/- 22 versus 33 +/- 16) were necessary to obtain similar numbers of embryos of quality with the long-acting GnRH-a. Implantation and delivery rates were significantly lower with the long-acting GnRH-a (32.8% versus 21.1%; 48.9% versus 29.1%, respectively).

CONCLUSIONS

As the long-acting GnRH-a might interfere with the luteal phase and embryo development, short-acting GnRH-a should be preferred for ovarian hyperstimulation in IVF-ET.

[Preclinical trials for mastering intracytoplasmic injection of a sole spermatozoid for the treatment of male infertility]

Before starting with the clinical application of ICS, aged unfertilized oocytes were gathered for training and were injected with a single sperm or without a spermatozoon as a control group for activation. Oocyte damage, initially as high as 40% was reduced to 15% after 60 oocytes. Normal fertilization (2PN) occurred in 18% of the injected oocytes. After this training period 1,488 metaphase II oocytes collected during 144 cycles were used for ICSI. Results were split up in 3 periods (n = 55, n = 24, n = 57) corresponding to the different improvements made in the technique. Results form ICSI in combination with MESA (n = 6) were analysed separately. Mean fertilization increased from 24% to 77%. Fertilization failures (18% of the cycles during the first period) vanished in the last period. Implantation rate improved from 7.4% to 11.4% and reached finally 26%. Pregnancy rate per oocyte retrieval was 16%, 25% and 54%. For the MESA group fertilization was 28%, implantation rate 17% and pregnancy rate 33% and only one fertilization failure was observed. A total of 50 pregnancies were obtained including 2 obtained after MESA and 2 with cryopreserved embryos. Four healthy children are born, 9 were early abortions, 37 pregnancies are still on-going. Preclinical practice on aged unfertilized oocytes seems useful before starting with clinical ICSI, as high initial oocyte damage could be reduced and subsequent clinical treatment successfully applied. Offering high fertilization and pregnancy rates in cases of infertility with severe male factor it is extremely worthwhile mastering this new technique.

Does zona pellucida thickness influence the fertilization rate?

In human in-vitro fertilization (IVF), the cumulus oophorus is routinely removed to assess fertilization and hence the thickness of the zona pellucida is measurable. This study aimed to measure the thickness of the zona pellucida and to assess its influence on fertilization rate in IVF programmes. The zona pellucida thickness varies from 10 to 31 microns with a mean of 17.5 microns. One-way analysis of variance revealed that in IVF trials performed with normal semen, the zona pellucida of fertilized oocytes (16.6 +/- 3.2 microns) was significantly thinner than the zona pellucida of unfertilized oocytes (18.9 +/- 4.0 microns; P < 0.001). As measured on micro-injected oocytes, the zona pellucida thickness did not change between ovulation and 16-20 h after fertilization. Zona pellucida thickness was not related to ooplasm diameter. In conclusion, zona pellucida thickness appears to be an additional factor that should be taken into account when interpreting the fertilization rate. Zona pellucida thickness influences sperm penetration, even when the spermatozoa are considered normal. From a clinical point of view, a thick zona pellucida (> or = 22 microns) could be an indicator for the use of micro-injection procedures.

Second polar body extrusion is highly predictive for oocyte fertilization as soon as 3 hr after intracytoplasmic sperm injection (ICSI)

OBJECTIVE

Our objective was to evaluate the time course and the predictive value of the extrusion of the second polar body after intracytoplasmic injection (ICSI) related to the fertilization rate, embryo cleavage and quality.

SETTING

The setting was the in vitro fertilization program of a university hospital.

PATIENTS

Twenty-one patients were treated with intracytoplasmic single sperm injection either for fertilization failure in IVF, low fertilization in IVF (< 5%), or severe male factors.

DESIGN

One hundred thirty-five of 205 metaphase 2 oocytes treated with intracytoplasmic single sperm injection were observed 1, 2, and 3 hr after the assisted fertilization procedure. Extrusion of the second polar body was recorded. For each of these oocytes, fertilization was noted 18 hr after ICSI and cleavage and embryo quality were assessed 24 hr later. The 70 remaining oocytes were used to assess a possible negative effect of repeated exposure to light microscopy.

RESULTS

The extrusion of the second polar body 3 hr after injection was an observation with a sensitivity of 0.87, a specificity of 0.58, and a high positive predictive value (0.90) toward oocyte fertilization. Twenty-nine and four-tenths percent of the oocytes extruded a second polar body within the first hour, 56.6% within the first 2 hr, and 78.3% had a second polar body 3 hr after injection. This time course was related neither to the speed of embryo cleavage nor to the embryo quality. Fertilization, cleavage, and embryo quality were not affected by repeated observation as deduced from comparison with the control group and confirmed by a high pregnancy (62% per oocyte retrieval) and implantation rate (22% per replaced embryo).

CONCLUSION

Oocytes can be checked, in all safety, 3 hr after a single sperm injection for the presence of a second polar to predict oocyte fertilization with a high certainty.

Intracytoplasmic single sperm injection: preclinical training and first clinical results

OBJECTIVE

Our purpose was to reduce oocyte damage before clinical application of intracytoplasmic single sperm injection by training on aged unfertilized oocytes.

DESIGN

Intracytoplasmic single sperm injection (ICSI) was accomplished by micromanipulation of sperm and oocytes.

PATIENTS

Thirty-four patients consented to donate unfertilized aged oocytes to train for ICSI. Forty-four patients suffering from severe male infertility were treated with ICSI.

INTERVENTION

Oocytes were inseminated by intracytoplasmic single sperm injection.

MAIN OUTCOME MEASURES

Oocyte damage and fertilization and pregnancy rates were the outcome measures.

RESULTS

One hundred fifty-one aged unfertilized oocytes were gathered for training of which 121 were injected with a single sperm and 30 without a spermatozoon as a control group for activation. Oocyte damage, initially as high as 40%, was reduced to 15% after 60 oocytes. Normal fertilization (2PN) occurred in 18%, and polyploidy in 4.4%. The cleavage rate was 69%; none of these embryos were transferred. In the control group, seven oocytes were damaged, seven (30%) showed one pronucleus, and one showed two pronuclei. No cleavage was observed in the control group. In the clinical trial, 44 patients (61 cycles) were clinically treated with the same ICSI procedure, including 575 of 721 collected oocytes. Damage was 13%, activation was 11%, normal fertilization was 30%, and 5 (1%) polypoid zygotes were observed. The fertilization rate ranged from 5 to 100%, with a mean of 39.5 +/- 4% (SE). Nine patients had no fertilization (15%). Ninety-six percent of the zygotes cleaved and 47% were at the four-cell stage 45 hr after injection. One hundred twelve embryos were replaced in 48 transfers (2.3 embryos/ET). One live birth, one miscarriage, and eight ongoing pregnancies were obtained (22%/ET).

CONCLUSION

Preclinical practice on aged unfertilized oocytes seems useful before starting clinical ICSI, as the high initial oocyte damage can be reduced and subsequent clinical treatment successfully applied.

Abnormal sperm-mucus penetration test predicts low in vitro fertilization ability of apparently normal semen

OBJECTIVE

To investigate whether Kremer's sperm-mucus penetration test may predict sperm fertilizing ability in IVF.

DESIGN

Kremer's test was prospectively performed on semen samples used for 66 consecutive IVF trials and compared with the fertilization rates and fertilization failure rates observed.

RESULTS

Fertilization rates were significantly reduced in cases of abnormal Kremer's test (42% versus 51%; n = 745 oocytes with a statistically insignificant increase in fertilization failure rates (21% versus 10%; n = 66 trials). For abnormal semen, fertilization rates (39% versus 39%; n = 208 oocytes) and fertilization failure rates (20% versus 28%; n = 17 trials) were similar regardless of Kremer's test result. For normal semen, an abnormal Kremer's test implied a significant decrease in fertilization rates (44% versus 54%; n = 537 oocytes) with a statistically insignificant increase in fertilization failure rates (21% versus 6%; n = 49 trials).

CONCLUSIONS

Abnormal Kremer's test results identify patients with a decreased in vitro fertilizing ability despite apparently normal semen samples and a group with very low fertilizing failure risk in case of normal semen samples and normal Kremer's test. Kremer's test does not add any predictive value to sperm analysis in the case of abnormal semen samples. These observations point out the importance of the male factor in fertilization failure even in the case of normal semen analysis.

Review of scientific contributions by the Belgian medical centers concerned with human in vitro fertilization and embryo transfer (IVF)

In vitro fertilization and embryo transfer (IVF) may be considered as a particular application of modern medical therapeutics linked to human reproduction. The treatment of human sterility therefore involves some fundamental human values such as life, love and death. The quality of this highly technological treatment with fast knowledge of outcome at the end of the patient's menstrual cycle has been evaluated since the early 80s. It is a typically multidisciplinary team effort involving medical doctors, biologists, laboratory technicians, nurses and clerks that is representative of modern medical practice. IVF covers much more than just embryology, as this review will explain. IVF developed in close relation with clinical and experimental research protocols, which are the major topics of this paper. The newness of the techniques used led to the necessary interactions between clinicians and biologists working on animal experimental embryology.

Comparative auto-controlled study between swim-up and Percoll preparation of fresh semen samples for in-vitro fertilization

This study compared swim-up and Percoll preparation of fresh semen samples for in-vitro fertilization. Sixty trials of in-vitro fertilization (IVF), 38 with normal semen and 22 with abnormal semen, comprising 734 oocytes were included in the study. Each semen sample was prepared by both a swim-up technique and a simplified discontinuous (50%, 70%, 90%) Percoll gradient. The oocytes for each trial were distributed at random between the two sperm preparations and incubated with the same number of motile spermatozoa. Percoll gradient preparation produced a significantly higher final concentration of spermatozoa than swim-up preparation (mean +/- SEM: 6.6 +/- 1.5 x 10(6)/ml versus 1.9 +/- 0.2 x 10(6)/ml; P less than 0.01) but a significantly lower sperm motility (69 +/- 2% versus 94 +/- 1%; P less than 0.001) and a lower number of normal forms (55 +/- 2% versus 64 +/- 2%; P less than 0.01). The ability of the Percoll gradient method to extract motile spermatozoa was higher than that of the swim-up technique (20 +/- 15.6% versus 0.8 +/- 13.6%). Nevertheless, the rates of fertilization (61%), fertilization failure (18%) and polyspermia (9%), embryo quality evaluated by mean embryo scores (3.8 +/- 0.3) and the mean number of spare embryos frozen per trial (1.4 +/- 0.3) were strictly identical in both groups. The 24 pregnancies (including three from frozen--thawed embryos) obtained in these 60 trials (40% per oocyte retrieval) could not be separated according to the sperm preparation method, as embryos from both groups were replaced together.(ABSTRACT TRUNCATED AT 250 WORDS)

The effect of pneumoperitoneum gases on fertilization, cleavage and pregnancy in human in-vitro fertilization and gamete intra-fallopian transfer

A prospective, randomized study was carried out, creating a pneumoperitoneum with 100% CO2 or with 5% CO2 in air and evaluating the effect(s) of these gas phases on fertilization, cleavage and pregnancy outcome in this in-vitro fertilization and embryo transfer programme. There was no significant difference in the fertilization rate when either 100% CO2 or 5% CO2 in air was used for insufflation during laparoscopy. Further, embryonic development and pregnancy rates also indicated no significant differences between the two groups. Similarly, the oocytes which were retrieved and replaced with spermatozoa in the gamete intra-Fallopian transfer programme using either 100% or 5% CO2, gave similar pregnancy rates. Furthermore, the fertilization and cleavage rates of the supernumerary oocytes were not significantly different in both groups.

Karyotypic evidence for the leukemic involvement of the erythroblasts in erythroleukemia

With the use of a monoclonal anti-glycophorin A antibody and flow cytometric cell sorting, an erythroleukemic bone marrow sample was separated in highly purified erythroblast and myeloblast fractions. Similar karyotypic anomalies were found in both cell populations as in the unseparated bone marrow. This study confirms that acute nonlymphocytic leukemia can originate at the level of a multipotential hemopoietic stem cell.

Cytogenetic and DNA-flow cytometric studies of separated blasts

With Percoll density gradients, blasts from peripheral blood and bone marrow could be separated with a significant enrichment, and very often with a high degree of purity. This allowed a study of selected cases, where the separated sample exhibited chromosome abnormalities and/or an abnormal DNA content distribution (as measured by DNA-flow cytometry). The anomalies were shown to be associated with the separated blast fraction.