Fractured zona oocytes in in-vitro fertilization cycles stimulated with gonadotrophin-releasing hormone analogue and human menopausal gonadotrophin

Are zona pellucida genes involved in recurrent oocyte lysis observed during in vitro fertilization?

PURPOSE

Complete oocyte lysis in in vitro fertilization (IVF) is a rare event, but one against which we remain helpless. The recurrence of this phenomenon in some women in each of their IVF attempts, regardless of treatment, together with the results of animal experiments led us to investigate the possible involvement of the genes encoding for the glycoproteins constituting the zona pellucida (ZP).

PATIENTS & METHODS

Over the last ten years, during which we treated over 500 women each year, three women suffered recurrent oocyte lysis during their IVF attempts in our Centre for Reproductive Biology. For each of these three cases, we sequenced the four genes and promoter sequences encoding the glycoproteins of the ZP. The sequence variations likely to cause a change in protein expression or structure, were investigated in a control group of 35 women who underwent IVF without oocyte lysis and with normal rates of fertilization.

RESULTS & CONCLUSION

We found no mutations in the ZP genes sequenced. Only some polymorphisms present in the control group and in the general population were detected, excluding their specific involvement in the phenotype observed. Thus, although we suspected that complete oocyte lysis was due to a genetic cause, it did not seem possible to directly incriminate the genes encoding the proteins of the ZP in the observed phenotype. Further study of the genes involved in the processing and organization of ZP glycoproteins may allow elucidation of the mechanism underlying recurrent oocyte lysis during in vitro fertilization.

Increased responsiveness may be associated with tripronuclear embryos in both conventional in vitro fertilization and intracytoplasmic sperm injection cycles using gonadotropin-releasing hormone agonist long protocols: a self-matched observational study

AIMS

In this self-matched observational study, the factors associated with the presence of tripronuclear (3PN) embryos, in conventional in vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI) cycles using gonadotropin-releasing hormone agonist long protocols, were investigated.

MATERIAL & METHODS

Clinical parameters were analyzed in 202 consecutive IVF-IVF or ICSI-ICSI matched cycles. The differences between the former and latter cycles were evaluated and compared according to the presence of 3PN embryos: group A [3PN (-) followed by 3PN (-)]; group B [3PN (-) followed by 3PN (+)]; group C [3PN (+) followed by 3PN (-)]; group D [3PN (+) followed by 3PN (+)].

RESULTS

For the IVF-IVF cycles, the E(2) on human chorionic gonadotropin injection day and the number of retrieved oocytes were increased in the 3PN (+) cycles compared to the 3PN (-) cycles of Groups B (2165.2 ± 1423.3 pg/mL vs 1468.2 ± 796.2 pg/mL, P=0.016; 10.4 ± 9.1 vs 7.2 ± 5.7, P=0.010) and C (2382.7 ± 1214.5 pg/mL vs 1553.0 ± 1119.6 pg/mL, P = 0.004; 13.1 ± 9.1 vs 9.1 ± 7.0, P < 0.001), while these outcome variables did not differ when the former and latter cycles in Groups A and D were compared. These trends were observed in the ICSI-ICSI cycles.

CONCLUSIONS

An increased responsiveness, based on the higher E(2) and greater number of retrieved oocytes, may be associated with the presence of 3PN in both conventional IVF and ICSI cycles.

A quantitative and morphological analysis of oocytes collected during 438 IVF cycles

PURPOSE

Our purpose was to determine if the number of retrieved oocytes, oocyte maturity, morphology, and other embryological parameters are related to the outcome of treatment.

METHODS

This retrospective study on 438 IVF cycles analyzes the numbers of retrieved oocytes, fractured zona oocytes, germinal vesical-stage oocytes, normally and abnormally fertilized oocytes, pregnancy rate, age of female partner, ovarian stimulation protocol, day of hCG injection, and serum estradiol concentration.

RESULTS

(1) Pregnancy rate increases with an increase in the number of retrieved oocytes, (2) a high incidence of fractured zona pellucida oocytes has a negative effect on fertilization rate but none on pregnancy rate, (3) a high incidence of immature oocytes is associated with improved fertilization and pregnancy rates, and (4) an inverse relationship between the presence of immature oocytes and oocytes with fractured zona pellucida is suggested.

CONCLUSIONS

Precise oocyte assessment in IVF cycles provides informations useful for the analysis and improvement of ovarian stimulation protocols.

Multinucleation in normally fertilized embryos is associated with an accelerated ovulation induction response and lower implantation and pregnancy rates in in vitro fertilization-embryo transfer cycles

OBJECTIVE

To determine if multinucleation in normally fertilized embryos is indicative of poor developmental or clinical pregnancy prognosis and to examine the ovulation induction characteristics associated with multinucleation.

DESIGN

Retrospective review.

SETTING

A tertiary care institution.

PATIENT(S)

Patients undergoing IVF-ET cycles (exclusive of other assisted reproductive technologies).

MAIN OUTCOME MEASURE(S)

Cycles in which embryos had at least 1 multinucleated blastomere were compared with cycles in which all blastomeres exhibited no nucleus or a single nucleus (control).

RESULT(S)

When >50% of transferred embryos contained multinucleated blastomeres there was a significant reduction in implantation (3.4% vs. 14.7%), clinical pregnancy (9.1% vs. 29.1%), and live birth rates (7.5% vs. 27.6%) when compared with transfers of control embryos. In conjunction with this finding, multinucleate cycles had higher E2 levels and more follicles on the day of hCG administration, a higher number of oocytes retrieved, a higher fertilization rate, and more embryos transferred per patient than did the cycles that produced control embryos. When multinucleated embryos were present, but not transferred, the developmental capacity of the sibling embryo was reduced.

CONCLUSION(S)

The evaluation of nuclear status using simple light microscopy is predictive of embryo developmental capacity and should be included in the embryo scoring system. The presence of multinucleated blastomeres in normally fertilized embryos is associated with a more effusive response to gonadotropin therapy and is indicative of a poor developmental outcome and lower clinical pregnancy rates.

Pituitary down-regulation in IVF cycles: is it necessary to use strict criteria?

PURPOSE

In a retrospective study we have reviewed the data of 570 consecutive IVF cycles in which a GnRH agonist (GnRHa) was started in the early follicular phase (long protocol). Cycles were divided in groups according to estradiol levels before HMG administration: A, < 20 pg/ml; B, 20 to 50 pg/ml; C, 51 to 100 pg/ml. Our objective was to determine if the degree of pituitary suppression had any effect on the ovarian response to stimulation by exogenous gonadotropins, and/or on the IVF outcome.

RESULTS

There were no significant differences in cycle cancellation rates, no. of days of stimulation and ampoules of HMG, serum estradiol after HMG, no. of oocytes retrieved and fertilization rates between groups. Pregnancy rates (19.4%, 21% and 31.8%/cycle, and 24.1%, 27.5% and 37.8% / embryo transfer, respectively) and live-birth rates (16.2%, 16.1% and 25.0%/cycle, 20.1%, 21.2% and 29.7%/embryo transfer, respectively) were also not significantly different.

CONCLUSIONS

The degree of pituitary suppression had no effects on either the ovarian response to gonadotropins (including HMG requirements) or the overall IVF results.