Association between body mass index and sperm quality and sperm DNA integrity. A large population study.

This study aimed to analyse whether the functional quality of spermatozoa is associated with body mass index (BMI). Semen samples were obtained from 1824 men undergoing fertility evaluation/treatment. Semen analysis was performed using World Health Organization (WHO) criteria, and morphology was evaluated with the motile sperm organelle morphology examination (MSOME). The percentages of sperm DNA fragmentation (using TdT (terminal deoxynucleotidyl transferase)-mediated dUTP nick-end labelling (TUNEL) assays), sperm chromatin packaging/underprotamination (using chromomycin A3/CMA3 ), mitochondrial damage (using MitoTracker Green) and apoptosis (using annexin V) were also assessed. At least 200 spermatozoa were examined in each evaluation. The following BMI values were used as cut-off points: ≤24.9 kg/m2 , 25-29.9 kg/m2 (overweight) and ≥30 kg/m2 (obese). High BMI negatively affects sperm concentration, vitality, motility and morphology (p < .05). Conversely, high BMI does not seem to be associated with impaired sperm DNA integrity, as assessed by DNA fragmentation, sperm protamination and sperm apoptosis (p > .05). However, increased BMI is associated with increased mitochondrial damage in spermatozoa (p < .05). In conclusion, given the adverse consequences of obesity and the possible effect of male BMI on assisted reproduction technology (ART) outcomes, the benefits of weight reduction should be discussed when counselling couples interested in fertility treatment.

Adjuvant therapy with GnRH agonists/tamoxifen in breast cancer should be a good council for patients with hormone receptor-positive tumours and wish to preserve fertility.

Infertility represents one of the main long-term consequences of the chemotherapy used for the adjuvant treatment of breast cancer. Approximately 60-65% of breast cancers express the nuclear hormone receptor in premenopausal women. Adjuvant endocrine therapy is an integral component of care for patients with hormone receptor-positive (HR+) tumours. The GnRH agonist (GnRHa) alone or in combination with tamoxifen produces results at least similar to those obtained with the different chemotherapy protocols in patients with HR+ breast cancer with respect to recurrence-free survival and overall survival. It is time to indicate adjuvant therapy with GnRHa associated with tamoxifen for patients with breast cancer (HR+ tumours) if they want to preserve their reproductive function. The evaluation of ovarian reserve tests: follicle stimulating hormone (FSH), anti-Mullerian hormone (AMH), inhibin B, antral follicle count (AFC) and ovarian volume 6 months, and 1 year after the end of therapy with GnRHa/tamoxifen must be realised. The recurrence-free survival and overall survival should be analysed. The major implication of this hypothesis will be to avoid adjuvant chemotherapy for patients with breast cancer (HR+ tumours) that request fertility preservation. It is expected that ovarian function should not be altered in almost all cases and subsequent pregnancy a real possibility.

Large nuclear vacuoles are indicative of abnormal chromatin packaging in human spermatozoa.

The aim of this investigation was to determine the presence of abnormal sperm chromatin packaging in spermatozoa with large nuclear vacuoles (LNV) selected via high magnification by analysing the pattern of chromomycin A3 (CMA3) staining. A prospective observational study was designed to analyse semen samples obtained from 66 men undergoing infertility diagnosis and treatment. The numbers of cells with normal (dull yellow staining of the sperm head/CMA3-negative) and abnormal (bright yellow fluorescence of the sperm head/CMA3-positive) chromatin packaging were determined on slides with normal and LNV spermatozoa. The presence of bright yellow fluorescence (CMA3-positive) was significantly higher (p < 0.0001) in spermatozoa with LNV than in normal spermatozoa (719/1351; 53.2% vs. 337/835; 40.3%, respectively), reflecting a higher percentage of abnormal chromatin packaging in spermatozoa with large LNV. Our data support the hypothesis that the presence of LNV reflects the presence of abnormal chromatin packaging, which may facilitate sperm DNA damage. As sperm nuclear vacuoles are evaluated more precisely at high magnifications using motile sperm organelle morphology examination (MSOME), the present results support the use of high-magnification sperm selection for intracytoplasmic sperm injection (ICSI).

Relationship between DNA damage and sperm head birefringence.

Birefringence or double refraction is the decomposition of a ray of light into two rays when it passes through an anisotropic material such as quartz. Sperm cells have been demonstrated to be optically anisotropic. The objective of this study was to evaluate the relationship between the pattern of human sperm head birefringence (SHBF) and DNA damage. A total of 26 patients with normal semen were included. DNA damage (fragmentation and denaturation) was evaluated in the sperm head in the context of birefringence, both total (SHBF-T) and partial (SHBF-P), by terminal deoxyribonucleotidyl transferase (TdT)-mediated dUDP nick-end labelling assay and acridine orange fluorescence, respectively. Positive DNA fragmentation in spermatozoa with SHBF-T (205/1053; 19.5%) was significantly higher (P<0.0001) than in spermatozoa that presented SHBF-P (60/820; 7.3%). However, the percentage of denatured DNA in spermatozoa with SHBF-T (824/1256; 65.6%) was not significantly different from the ones with SHBF-P (666/1009; 66.0%). In conclusion, the data support a positive relationship between spermatozoa with total SHBF in their head and increased DNA fragmentation.

Significance of extruded nuclear chromatin (regional nuclear shape malformation) in human spermatozoa: implications for ICSI.

The aim of this study was to determine the extent of DNA fragmentation and the presence of denatured single-strand or normal double-strand DNA in spermatozoa with extruded nuclear chromatin (ENC) selected by high magnification. Fresh semen samples from 55 patients were prepared by discontinuous isolate concentration gradient. Spermatozoa with normal nucleus (NN) and ENC were selected at 8400× magnification and placed on different slides. DNA fragmentation was determined by TUNEL assay. Denatured and double-stranded DNA was identified by the acridine orange fluorescence method. DNA fragmentation was not significantly different (p = 0.86) between spermatozoa with ENC (19.6%) and those with NN (20%). However, the percentage of spermatozoa with detectable denatured-stranded DNA in the ENC spermatozoon group (59.1%) was significantly higher (p < 0.0001) than in the NN group (44.9%). The high level of denatured DNA in spermatozoa with ENC suggests premature decondensation and disaggregation of sperm chromatin fibres. The results show an association between ENC and DNA damage in spermatozoa, and support the routine morphological selection and injection of motile spermatozoa at high-magnification intracytoplasmic sperm injection.

Motile sperm organelle morphology examination is stricter than Tygerberg criteria.

The present study aimed to evaluate the correlation between the motile sperm organelle morphology examination (MSOME) and a well-known sperm morphology classification (Tygerberg criteria). For MSOME, spermatozoa were analysed at x8400 magnification by inverted microscope equipped with Nomarski differential interference contrast optics, Uplan Apo x100 oil/1.35 objective lens and variable zoom lens. By Tygerberg criteria, the semen underwent morphological evaluation as described in the literature. Regression analysis demonstrated significant positive correlation between percentage of normal sperm forms by Tygerberg criteria and by MSOME (r = 0.83, P < 0.0001). However, the incidence of normal spermatozoa by Tygerberg criteria (9.4%) was significantly higher (P < 0.0001) than under MSOME (3.3%). Despite the highly positive correlation, MSOME is a much stricter criterion of sperm morphology classification, since it identifies vacuoles and chromatin abnormalities that are not evaluated with the same precision by the analysis of Tygerberg criteria. MSOME should be included among the routine criteria for semen analysis. In addition, MSOME should be used for selection of spermatozoa for intracytoplasmic sperm injection based on the already published literature, as this is a good selection tool.

Relationship between visualization of meiotic spindle in human oocytes and ICSI outcomes: a meta-analysis.

The objective of this meta-analysis was to investigate the influence of meiotic spindle visualization in human oocytes on intracytoplasmic sperm injection (ICSI) outcomes. Search strategies included on-line surveys of databases (MEDLINE, EMBASE, Science Citation Index, Cochrane Controlled Trials Register and Ovid). The fixed effect was used for odds ratio. Ten trials fulfilled the inclusion criteria comparing in-vitro and clinical ICSI outcomes with or without visualization of meiotic spindle in fresh and in-vivo matured oocytes. According to the meta-analysis, the results showed statistically significant higher fertilization rate (P < 0.0001) when the meiotic spindle was viewed than when it was not. Moreover, the percentage of pro-nuclear-stage embryos with good morphology (P = 0.003), cleavage rate (P < 0.0001), percentage of day-3 top-quality embryos (P = 0.003) and percentage of embryos that reached the blastocyst stage (P < 0.0001) were statistically significantly better among embryos derived from oocytes in which meiotic spindle was viewed compared with those in which meiotic spindle was not observed. However, these differences were not observed in the clinical pregnancy or implantation rates. This observation has clinical relevance mainly in countries where there is a legal limit on the number of oocytes to be fertilized. However, additional controlled trials are needed to further confirm these results.

Significance of large nuclear vacuoles in human spermatozoa: implications for ICSI.

The aim of this study was to determine the extent of DNA fragmentation and the presence of denatured single-stranded or normal double-stranded DNA in spermatozoa with large nuclear vacuoles (LNV) selected by high magnification. Fresh semen samples from 30 patients were prepared by discontinuous isolate concentration gradient. Spermatozoa with normal nucleus (NN) and LNV were selected at x8400 magnification and placed on different slides. DNA fragmentation was determined by TUNEL assay. Denatured and double-stranded DNA was identified by the acridine orange fluorescence method. DNA fragmentation in spermatozoa with LNV (29.1%) was significantly higher (P < 0.001) than in spermatozoa with NN (15.9%). Therefore, cleavage of genomic DNA in low molecular weight DNA fragments (mono- and oligonucleosomes), and single-strand breaks (nicks) in high molecular weight DNA occur more frequently in spermatozoa with LNV. Similarly, the percentage of denatured-stranded DNA in spermatozoa with LNV (67.9%) was significantly higher (P < 0.0001) than in spermatozoa with NN (33.1%). The high level of denatured DNA in spermatozoa with LNV suggests precocious decondensation and disaggregation of sperm chromatin fibres. The results show an association between LNV and DNA damage in spermatozoa, and support the routine morphological selection and injection of motile spermatozoa at high magnification for ICSI.

The effects of male age on sperm DNA damage in an infertile population.

The objective was to investigate the influence of age on sperm DNA damage. Semen samples were collected from 508 men in an unselected group of couples attending infertility investigation and treatment. DNA fragmentation in spermatozoa was measured by TdT (terminal deoxynucleotidyl transferase)-mediated dUTP nick-end labelling (TUNEL) assay; at least 200 spermatozoa in randomly selected areas of microscope slides were evaluated using a fluorescent microscope and the percentage of TUNEL positive spermatozoa was determined. The number of cells with red fluorescence (TUNEL positive) was expressed as a percentage of the total sample [DNA fragmentation index (DFI)]. Age was treated as a continuous variable for regression and correlation analysis. The following male age groups were used: Group I: < or =35 years, Group II: 36-39 years, and Group III: > or =40 years. DFI was significantly lower in Group I than in Group II (P = 0.034) or III (P = 0.022). There was no difference in DFI between Groups II and III. In addition, regression analysis demonstrated a significant increase in sperm DFI with age (P = 0.02). TUNEL assay clearly demonstrates an increase in sperm DNA damage with age.

Recombinant LH supplementation to recombinant FSH during induced ovarian stimulation in the GnRH-antagonist protocol: a meta-analysis.

This study aims to compare the efficacy of recombinant LH (rLH) supplementation for ovarian stimulation in gonadotrophin-releasing hormone-antagonist protocol for IVF/intracytoplasmic sperm injection cycles. Search strategies included online surveys of databases. The fixed effects model was used for odds ratio (OR) and effect size (weighted mean difference, WMD). Five trials fulfilled the inclusion criteria. When the meta-analysis was carried out, advantages were observed for the LH supplementation protocol with respect to higher serum oestradiol concentrations on the day of human chorionic gonadotrophin administration P < 0.0001; WMD: 514, 95% CI 368, 660) and higher number of mature oocytes (P = 0.0098; WMD: 0.88, 95% CI 0.21, 1.54). However, these differences were not observed in the total amount of recombinant FSH (rFSH) administered, days of stimulation, number of oocyets retrieved, the clinical pregnancy rate per oocyte retrieval, the implantation rate and miscarriage rate. This result demonstrates that the association of rLH with rFSH may prevent any decrease in oestradiol after antagonist administration and that a significantly higher number of mature oocytes was available for laboratory work. Nevertheless, it failed to show any statistically significant difference in clinically significant end-points in IVF (implantation and pregnancy rates). Additional randomized controlled trials are needed to confirm these results further.

GnRH agonist versus GnRH antagonist in poor ovarian responders: a meta-analysis.

The aim of this meta-analysis was to compare the efficacy of gonadotrophin antagonist (GnRH-ant) versus GnRH agonist (GnRHa) as coadjuvant therapy for ovarian stimulation in poor ovarian responders in IVF/intracytoplasmic sperm injection cycles. Search strategies included on-line surveys of databases such as MEDLINE , EMBASE and others. A fixed effects model was used for odds ratio (OR) and effect size (weighted mean difference, WMD). Six trials fulfilled the inclusion criteria (randomized controlled trials). There was no difference between GnRH-ant and GnRHa (long and flare-up protocols) with respect to cycle cancellation rate, number of mature oocytes and clinical pregnancy rate per cycle initiated, per oocyte retrieval and per embryo transfer. When the meta-analysis was applied to the two trials that had used GnRH-ant versus long protocols of GnRHa, a significantly higher number of retrieved oocytes was observed in the GnRH-ant protocols [P=0.018; WMD: 1.12 (0.18, 2.05)]. However, when the meta-analysis was applied to the four trials that had used GnRH-ant versus flare-up protocols, a significantly higher number of retrieved oocytes (P=0.032; WMD: -0.51, 95% CI -0.99, -0.04) was observed in the GnRHa protocols. Nevertheless, additional randomized controlled trials with better planning are needed to confirm these results.

Implantation sites after embryo transfer into the central area of the uterine cavity.

A total of 63 pregnancies (47 singleton, 15 twin, 1 triplet) from intracytoplasmic sperm injection cycles were analysed. In all embryo transfers, the catheter was introduced into the endometrial cavity guided by abdominal ultrasound, with the catheter tip placed at the middle point of the endometrial cavity. Gestational sacs (GS) were located 21-24 days after transfer (gestational age=5 weeks) by two-dimensional and three-dimensional transvaginal ultrasound. The uterine cavity was divided into three parts: upper, middle and lower. Furthermore, the upper region was subdivided into right, middle and left areas, and the middle region was subdivided into right and left areas. The frequency of gestational sacs in each area was evaluated. In singleton pregnancies 66.0% (31/47) of the GS were detected in the upper region, 29.8% (14/47) in the middle region and 4.2% (2/47) in the lower region. In multiple pregnancies (twins and triplet) 45.5% (15/33) of the GS were detected in the upper region, 51.5% (17/33) in the middle region and 3.0% (1/33) in the lower region. In conclusion, the results demonstrate that when embryos are transferred to the central area of the uterine cavity there is an increase in implantation rate in the middle region compared with the rate expected in naturally conceived pregnancies (9-15%).

Implantation failures: success of assisted hatching with quarter-laser zona thinning.

Implantation failure after IVF is one of the factors associated with a reduced chance of pregnancy for some patients. Assisted hatching methodologies are designed to facilitate the embryo's escape from the zona pellucida, and this strategy has been suggested as a means of improving pregnancy rates in patients with previous implantation failure. The aim of this prospective and randomized study was to evaluate the efficacy of quarter-laser zona thinning assisted hatching (qLZT-AH) in improving the implantation of embryos in patients with previous implantation failure. A total of 150 patients with a history of previous implantation failure were treated with intracytoplasmic sperm injection, and allocated into two groups: group 1, only one previous implantation failure, and group 2, repeated implantation failures. The patients in each group were randomized at the time of embryo transfer into a control group (no qLZT-AH) or experimental group where qLZT-AH was performed. For patients with repeated implantation failures, the implantation rate in those who received laser-thinned embryos was significantly higher (P = 0.02) than in those whose embryos were not laser-thinned (10.9 and 2.6% respectively). However, this difference was not observed in patients who presented with only one previous implantation failure. The data demonstrate that qLZT-AH is an effective strategy for improving the implantation of embryos in patients with repeated implantation failures.

Increased implantation and pregnancy rates obtained by placing the tip of the transfer catheter in the central area of the endometrial cavity.

The influence of endometrial cavity length (ECL) on implantation and pregnancy rates after 400 embryo transfers was studied prospectively in a population with the indication of IVF/intracytoplasmic sperm injection (ICSI). The tip of the transfer catheter was placed above or below the half point of the ECL in a randomized manner. Two analyses were performed: (i) absolute position (AP); embryo transfers were divided into three groups according to the distance between the end of the fundal endometrial surface and the catheter tip (DTC - distance tip catheter): AP1 (n = 212), 10-15 mm; AP2 (n = 158), 16-20 mm; and AP3 (n = 30), > or =21 mm. (ii) relative position (RP)--embryo transfers were divided into four groups according to their RP [RP = (DTC/ECL) x 100]: RP1 (n = 23), < or =40%; RP2 (n = 177), 41-50%; RP3 (n = 117), 51-60%; and RP4 (n = 83), > or =61%. Analysis based on relative distance revealed significantly higher implantation and pregnancy rates (P < 0.05) in more central areas of the ECL. However, analysis based on absolute position did not reveal any difference. In conclusion, the present results demonstrated that implantation and pregnancy rates are influenced by the site of embryo transfer, with better results being obtained when the catheter tip is positioned close to the middle area of the endometrial cavity. In this respect, previous analysis of the ECL is the fundamental step in establishing the ideal site for embryo transfers.

Concerns regarding the follow-up of children conceived after assisted reproduction in Latin America.

Children born through assisted reproduction are not usually followed up in Latin America. However, in spite of all the social-economic and cultural complexity of this part of the world, professionals involved in assisted reproduction should not relinquish the responsibility of following up these children. In May 2002, the Centre for Human Reproduction Sinhá Junqueira, started a specific project for evaluation and follow-up of its children. It is the first centre in Brazil, and probably in Latin America, with this aim, and this paper reports initial results concerning the intellectual development of these children.

Best site for embryo transfer: the upper or lower half of endometrial cavity?

BACKGROUND: The objective of the present study was to determine the importance of the site of embryo transfer (upper or lower half endometrial cavity) on implantation and clinical pregnancy rates. METHODS: A total of 400 transfers guided by ultrasound were randomly assigned to two groups according to the distance between the uterine fundus and the catheter tip at the time of embryo placement. Group I (n = 200) consisted of transfers corresponding to a distance of < 50% of the endometrial cavity length (ECL), i.e. transfer in upper half of the cavity; and group II (n = 200) consisted of transfers corresponding to a distance of > or = 50%, of the ECL, i.e. transfer in lower half of cavity. The Student's t-test, Mann-Whitney test and Fisher's exact test were used where appropriate. RESULTS: The general characteristics of the study population and the main transfer cycle characteristics had an equal distribution (P > 0.05) between groups I and II. No significant difference in implantation or pregnancy rates was observed between groups I and II. CONCLUSION: The implantation or pregnancy rates were similar whether the embryos were deposited in the upper or lower half of the endometrial cavity.

Comparison of the psychological evaluation test and classical psychoanalysis in infertile women.

This study aims to compare a psychological evaluation test to classical psychoanalysis in infertile women. Two hundred women were submitted to the Psychological Evaluation Test (PET). The sum of the scores for the responses ranged from 15 to 60 points, with scores >/=30 points being defined as 'psycho-emotional maladjustment' (cut-off point: median + 25%). For comparison, the patients were simultaneously submitted to a psychological examination by a psychologist, who was unaware of the PET results. Of the 200 patients, 66 (33%) presented a test with >/=30 points ('psycho-emotional maladjustment') and 134 (67%) a test with <30 points (normal). Upon psychological examination, 105 (52.5%) presented an abnormal evaluation and 95 (47.5%) a normal evaluation. For the PET, statistical analysis showed 82% efficiency, 62% sensitivity, 98% positive predictive value, 99% specificity, 70% negative predictive value, likelihood ratio for a positive test result 62, and likelihood ratio for negative test result 0.38. The PET proved to be a useful clinical instrument, being of help in the selection of patients with psychological needs induced by infertility.

A prospective, randomized comparison of two commercial media for ICSI and embryo culture.

PURPOSE: The aim of this prospective, randomized study was to compare the results obtained in ICSI with two culture media, P-1 (Irvine Scientific) and IVF-50 (Scandinavian IVF Science). METHODS: A total of 182 patients undergoing ICSI treatment were randomly included in this study and divided in two groups: Group I: P-1 medium (n = 91) or Group II: IVF-50 medium (n = 91). All the embryos were transferred on the second day. RESULTS: Patient age did not differ (p = .29) between Group I (34.8 +/- 4.8) and Group II (34.0 +/- 4.5). The number of oocytes retrieved from Group I (10.6 +/- 6.7) was also similar (p = .49) to that retrieved from Group II (11.1 +/- 6.4). In addition, there was no difference (p = .25) in the number of oocytes retrieved at metaphase II between Group I (7.9 +/- 4.6) and Group II (8.7 +/- 4.6). Normal fertilization rates, abnormal fertilization rates, and cleavage rates were similar (p = .62, p = .48, and p = .9, respectively) between Group I (68.4 +/- 23.3%, 6.7 +/- 10.3%, and 98.7 +/- 4.6%) and Group II (65.3 +/- 26.2%, 9.0 +/- 13.8%, and 98.9 +/- 3.9%, respectively). The embryo score was also similar (p = .62) for both groups (Group I: 31.9 +/- 14.0 and Group II: 33.4 +/- 15.8). There was no difference in the number of embryos transferred (p = .69) between Group I (2.8 +/- 1.0) and Group II (2.8 +/- 1.1). In addition, pregnancy rates/puncture, pregnancy rates/transfer, implantation rates, and abortion rates were also similar for Group I (36.2%, 37.0%, 17.4%, and 12.1%, respectively) and Group II (31.8%, 33.7%, 15.8%, and 10.3%, respectively) (p = .64, p = .75, p = .72, and p = 1.0, respectively). CONCLUSIONS: There were no differences in the results obtained with culture media P-1 (Irvine Scientific) and IVF-50 (Scandinavian IVF Science) for ICSI and embryo culture.

Comparison of the cryopreservation of human embryos obtained after intracytoplasmic sperm injection with a slow cooling or an ultrarapid cooling procedure.

PURPOSE: Our purpose was to compare an ultrarapid method (URM) modified with dimethyl sulfoxide (Me2SO) to a slow method (SM) with propanediol (PROH) for the cryopreservation of extra human embryos in a program of intracytoplasmic sperm injection (ICSI). METHODS: The extra embryos of 160 patients were cryopreserved in a prospective and randomized manner (drawing lots) by a modified URM (3 M Me2SO/0.25 M sucrose/thawing in three sucrose gradients) (Group I) or by a SM (1.5 M Propanediol/program 0-Cryologic CL863) (Group II). A total of 103 cycles has been thawed thus far. The number of thawed cycles was 58 for group I and 45 for group II. RESULTS: The mean age (group I, 31.3 +/- 4.5; group II, 31.9 +/- 4.3) did not differ between the groups (P = 0.38). The number of frozen embryos (group I, 6.6 +/- 3.2; group II, 6.5 +/- 3.2) was similar (P = 0.49) for the two groups, as was the number of thawed embryos (P = 0.52) (group I, 6.5 +/- 2.9; group II, 6.2 +/- 3). The survival rate was higher (P < 0.01) for group II (83.3 +/- 23%) than for group I (69.2 +/- 28.7%). The cleavage rate was also higher (P < 0.01) for group II (56.8 +/- 31%) compared with group I (24.2 +/- 22.4%). The number of embryos transferred did not differ (P = 0.14) between the groups (group I, 3.16 +/- 1.2; group II, 3.5 +/- 1.0). The implantation rate (group I, 6.3%; group II, 13.8%) was significantly different between groups (P = 0.034). Pregnancy rates per thawed and transferred cycle were higher for group II (33.3 and 36.6%, respectively) compared with group I (13.8 and 16%, respectively), and these differences were significant (P = 0.03 and P = 0.03, respectively). CONCLUSION: The data obtained suggest that the SM is superior to the URM for the cryopreservation of extra embryos after ICSI.

Embryo selection by the first cleavage parameter between 25 and 27 hours after ICSI.

PURPOSE: The objective of this study was to assess first embryo cleavage (FEC) 25-27 h after intracytoplasmic sperm injection (ICSI) as a parameter for the embryo selection process. METHODS: From January 1998 to December 1999, a total of 670 patients were subjected to the ICSI programme at the Centre for Human Reproduction, Sinhá Junqueira Maternity Foundation, and the FEC parameter was evaluated in three situations. RESULTS: In the first, a total of 300 zygotes were analyzed on the basis of a score (16-18 h after ICSI) and observed for the presence or absence of FEC (25-27 h after ICSI). A significant (p < 0.02) presence of FEC was observed in zygotes with a score of 15 (ideal score). In the second, a total of 200 patients were selected and divided into two groups matched for age and laboratory performance. Group I (n = 100) was subjected to transfer of embryos with the absence of FEC only (since in this cycle no embryos with FEC were detected within 25-27 h after ICSI) and Group II (n = 100) was subjected to transfer of embryos with the presence of FEC only. The age of Group I patients (33.8 +/- 4.2 years) did not differ significantly (p = 0.50) from that of Group II patients (33.5 +/- 4.3 years). The number of embryos transferred was similar (p = 0.07) for Group I (2.7 +/- 1.1) and Group II (2.9 +/- 0.88). In Group II, the 17.5% implantation rate was significantly higher (p < 0.01) than the 5.9% rate obtained for Group I. The pregnancy rate for Group II was significantly higher (p < 0.01) (33%) than that for Group I (12%). The incidence of abortion was 16.6% in Group I as compared with 6% in Group II. In the third situation, we observed the frequency of embryos with FEC in 36 patients whose implantation rate was 100% (ideal result) and obtained a value of 82%. CONCLUSIONS: The data suggest that the presence of the FEC parameter that was evaluated 25-27 h after ICSI could be used to select embryos with a higher implantation power. The data reported here may justify routine analysis of embryos with FEC for the process of embryo selection after ICSI.