The effect of polyploidy on embryo cleavage after in vitro fertilization in humans

Conventional IVF versus ICSI in sibling oocytes from couples with endometriosis and normozoospermic semen

PURPOSE

This study compares the fertilization rate and embryonic development of oocytes randomly inseminated by conventional IVF or ICSI in patients with endometriosis and normozoospermic semen during IVF cycles.

METHODS

Sibling oocytes were randomized to be inseminated either by ICSI or IVF. Rates of fertilization, cleavage, blastulation and embryonic morphology were assessed.

RESULTS

A total of 786 sibling cumulus-oocyte complexes (COC) were randomized between insemination by conventional IVF (387 COC) or ICSI (399 COC). A significantly higher fertilization rate was found in the ICSI group (ICSI versus IVF, 73.3±23 % versus 54.7±31.9 % respectively; P=0.003), yielding a higher mean number of day 2 embryos (5.2±3.4 versus 3.6±2.9 respectively; P=0.002). Triploid fertilization rate (3PN/COC) was significantly higher in the IVF group compared to the ICSI group (3.9±8.7 % versus 0.9±3.1 % respectively; P=0.02). The morphology score and rate of development of day 2 and 3 embryos were not different between the two groups. Comparison of embryo transfer cycles in which either IVF or ICSI only embryos were transferred did not reveal any statistically significant differences in pregnancy or implantation rates.

CONCLUSION

ICSI appears to be a better treatment option than conventional IVF in endometriosis-associated infertility, since it offers the advantages of higher fertilization rate and mean number of embryos and lower rate of total fertilization failure and triploid fertilization.

Benefit of intracytoplasmic sperm injection in patients with a high incidence of triploidy in a prior in vitro fertilization cycle

OBJECTIVE

To test the hypothesis that intracytoplasmic sperm injection (ICSI) overcomes a high incidence of tripronucleate zygotes resulting from standard insemination in a previous cycle.

DESIGN

A retrospective analysis of matched-pair cycles.

SETTING

Assisted reproductive technologies (ART) program of Brigham and Women's Hospital.

PATIENT(S)

Ninety-five patients with a > or = 20% incidence of tripronucleate zygotes in an IVF cycle with use of ICSI in a subsequent attempt.

INTERVENTION(S)

Cycles with either standard insemination or ICSI.

MAIN OUTCOME MEASURE(S)

Incidence of diploid (2pn) and triploid (3pn) zygotes and number and quality of embryos obtained.

RESULT(S)

Patient age, ampules of gonadotropin used, peak E2, number of follicles at hCG trigger, and total number of oocytes were all significantly higher in the ICSI cycles, but the number of mature oocytes did not differ. After ICSI, the percentage of 2pn was higher (65.0% vs. 34.1%) and the percentage of 3pn was lower (5.0% vs. 33.9%) than after IVF, and more diploid embryos were obtained with ICSI (5.5 +/- 3.7 vs. 3.4 +/- 2.2 [mean +/- SD]). There was no difference in embryo quality between the two groups.

CONCLUSION(S)

ICSI appears beneficial in women with a high 3pn occurrence from IVF because it increases the number of diploid zygotes without affecting embryo quality.

Analysis of factors associated with multinucleate formation in human IVF

This study was carried out to analyse if some of the sperm parameters assessed by computer-aided sperm analysis (CASA) are associated with multinucleate formation in human in vitro fertilization (IVF). In the present study, 137 IVF-embryo transfer (ET) treatment cycles in which pronucleate formation could be observed were enrolled. Sperm parameters after swim-up were assessed using CASA and strict criteria. Thirty-two (2.3%) of 1368 oocytes fertilized were judged as multinucleate formation, which occurred in 25 of 137 IVF-ET treatment cycles, giving the incidence of 18.2%. The factors associated with multinucleate formation were analysed. There were significant differences of the numbers of oocytes collected (13.9 vs. 9.2; p=0.028), fertilization rate (88.8% vs. 71.9%; p=0.011), curvilinear velocity (VCL) (162.7 microm/sec vs. 149.1 microm/sec; p=0.034), average path velocity (VAP) (100.3 microm/sec vs. 93.1 microm/sec; p=0.016), and amplitude of lateral head displacement (ALH) (5.9 microm vs. 5.3 microm; p=0.046) between 25 cycles with multipronucleate formation and 112 cycles with two pronucleate formations. However, there were no significant differences of women's age or the number of sperm inseminated between the two groups. These findings suggest that prediction of multinucleate formation in human IVF might be possible in patients when the number of oocytes collected is higher and sperm motility parameters after swim-up are faster. However, prevention of multinucleate formation seems to be unnecessary because a higher successful IVF-ET outcome is expected as a result of the excellent fertilization rate in these patients.

Formulation of a protein-free medium for human assisted reproduction

The optimal concentrations of individual amino acids, antioxidants, vitamins, osmolytes and energy sources were determined using a 1-cell Swiss outbred (SO) and or F(1) [(CBAxC57BL/6J)xSO] mouse assay in Earle's balanced salt solution containing bovine serum albumin. Based on the findings of these experiments, a number of media were formulated. Of these, the medium showing optimal embryo development and a significantly higher blastocyst hatching rate was investigated further. A protein-free medium (ART-7) was formulated and assessed using 1-, 2- and 4-cell SO mouse embryos. The generation of viable human embryos in the ART-7 series of media in micro- and ultra micro-droplet culture under oil with and without cumulus co-culture following intracytoplasmic sperm injection (ICSI) was investigated. The quality of sibling day 2 human embryos generated in the ART-7 media series was statistically comparable to or better than control embryos. The ART-7 medium was not toxic to human spermatozoa. Fertilization by conventional IVF and subsequent embryo development was not affected. A clinical trial of ICSI-derived embryos generated in the protein-free medium, with and without cumulus co-culture, has resulted in clinical pregnancies (10 of 20 transfers) of which two have proceeded to term, and the remaining patients are in various stages of pregnancy.

Super high estradiol response to gonadotropin stimulation in patients undergoing in vitro fertilization

The likelihood of establishment of a term pregnancy from in vitro fertilization (IVF) is related to the estradiol (E2) pattern and peak level. To examine the influence of super high E2 peak levels (greater than or equal to 2000 pg/ml), we reviewed the clinical outcomes of all IVF cycles with follicular phase E2 levels greater than 2000 pg/ml from May 1982 through June 1987. Among 1651 IVF cycles initiated during this time, 102 cycles (6.2%) had super high E2 levels. Twenty-seven of these cycles occurred in 34 IVF attempts in 12 women. Stimulation was performed with human menopausal gonadotropin (hMG) in 96 cycles and follicle-stimulating hormone (FSH) in 6 cycles. A mean of 9.3 +/- 0.7 oocytes per cycle was recovered, of which 5.5 +/- 0.5 fertilized and underwent cleavage. In 11 cycles, with a mean of 6.8 oocytes recovered, none fertilized. Polyploid fertilization occurred in 23 of 90 cycles (25.6%), and 40 of 558 fertilized oocytes (7.2%). From these cycles, 10 clinical pregnancies (9.8%) have resulted: 6 pregnancies in 59 cycles with luteal-phase progesterone support (10.2%) and 4 pregnancies in 31 cycles without luteal-phase progesterone support (12.9%). Among the 1549 cycles with peak E2 levels less than or equal to 2000 pg/ml, 143 (9.2%) resulted in clinical pregnancies. We conclude that there is a small subset of patients who will have super high E2 responses to gonadotropin stimulation and that there is a tendency to stimulate repetitively in this fashion.(ABSTRACT TRUNCATED AT 250 WORDS)

Qualitative changes in protein synthesis associated with polyspermic fertilization of human eggs

To investigate the early molecular events in human oocytes that are triggered by fertilization, the authors examined the pattern of polypeptides synthesized by unfertilized and dispermic embryos obtained through an in vitro fertilization and embryo transfer (IVF-ET) program. Compared with unfertilized oocytes of the same postovulatory age, the de novo protein synthesis in tripronuclear dispermic zygotes (21 hours postinsemination) was characterized by the appearance of three novel protein bands with molecular weights of 41.2, 35.3, and 26.0 kD. Concomitant with these changes, these zygotes showed the disappearance of bands at 54.0, 36.5, and 28.0 kD, along with the decreased synthesis of a protein band at 42.5 kD. Although 24% of the aged unfertilized oocytes exhibited bands corresponding to 41.2 and 35.3 kD, the 26.0 kD protein is restricted to the tripronuclear embryos. The significance of these results is discussed in relation to the use of polyspermic human oocytes as a model for the study of the early molecular events triggered by fertilization.

Success rate in gamete intrafallopian transfer using low and high concentrations of washed spermatozoa

The effect of a reduced number of spermatozoa on pregnancies and miscarriages was studied retrospectively in 307 consecutive gamete intrafallopian transfer (GIFT) cycles. The number of spermatozoa introduced per GIFT in each group was as follows: 100,000 (group I), 50,000 (group II), 10,000 (group III), 5,000 (group IV), and 2,500 (group V), which gave a pregnancy rate of 20%, 38%, 37%, 30%, and 24%, respectively (differences were not significant). With respect to the pregnancies, no correlation was found between the number of spermatozoa transferred and the cause of infertility. In the male factor group also no significant difference was observed in the pregnancy rate when the sperms were reduced from 100,000 to 2,500. Lowering the number of sperms in GIFT did not reduce the abortion rate, which remained around 33%. It was the patients with unexplained infertility who benefited most from the GIFT procedure. Their pregnancy rate was significantly higher than the pregnancy rate of those who had endometriosis, or andrologic or immunologic disorders.