Correlation between oocyte morphology and the embryo aneuploidy rate in IVF cycles

Abstract

Purpose: To evaluate the aneuploidy rates of 13, 18, and 21 and the X and Y chromosomes in embryos from patients with morphologically normal oocytes and different oocyte dysmorphisms.

Methods: This prospective cohort study included 84 patients treated with in vitro fertilization (IVF) at a single academic center. The patients were divided into the following three groups: group 1 – women with cytoplasmic dysmorphisms (n?=?28), group 2 – women with extracytoplasmic dysmorphisms (n?=?28), and group 3 – women with morphologically normal oocytes (n?=?28). One blastomere from each embryo was analyzed for aneuploidies of chromosomes 13, 18, 21, X, and Y.

Results: The highest prevalence of aneuploid embryos was observed in the group 1 (68.4%) followed by the group 2 (38.9%) and the group 3 (31.3%) (р?<?0.0001). The adjusted OR for receiving an aneuploid embryo in the case of cytoplasmic dysmorphism was 3.6 (95% CI?=?1.8; 7.2), in the case of extracytoplasmic dysmorphisms – 1.3 (95% CI?=?0.7; 2.1).

Conclusions: Women with morphological oocyte abnormalities are at risk for developing aneuploid embryos during IVF cycles. We recommend that woman with cytoplasmic oocyte dysmorphisms receive additional genetic counseling to define the indications for the genetic screening of embryos.     

Influence of individual sperm morphology on fertilization,embryo morphology,and pregnancy outcome of intracytoplasmic sperm injection

OBJECTIVE:To evaluate the influence of morphology of individual spermatozoa on fertilization and pregnancy outcome. DESIGN: Retrospective analysis. SETTING: An IVF center in an institutional research environment. PATIENT(S): Fertilization and embryo quality according to individual sperm morphology were analyzed in 662 consecutive ICSI cycles. Pregnancy outcome was evaluated for these cycles and an additional 1005 consecutive ICSI cycles. INTERVENTION(S): ICSI was performed using sperm cells of ejaculated, epididymal, or testicular origin. Observation through an inverted microscope was used to prospectively classify injected sperm cells as normal or morphologically abnormal. MAIN OUTCOME MEASURE(S): Oocyte fertilization, embryo morphology, and pregnancy outcome of unmixed embryo transfers. RESULT(S): Injection of morphologically abnormal spermatozoa (irrespective of origin) resulted in a lower fertilization rate (60.7%) than did injection of morphologically normal spermatozoa (71.7%). Embryo cleavage quality did not differ between groups. Higher pregnancy and implantation rates were obtained in patients with normal sperm morphology (36.7% and 18.7%, respectively) than in those with abnormal sperm morphology (20.2% and 9.6%). CONCLUSION(S): Individual sperm morphology assessed at the moment of ICSI correlated well with fertilization outcome but did not affect embryo development. The implantation rate was lower when only embryos resulting from injection of an abnormal spermatozoon were available.     

Correlation of follicular diameter with oocyte recovery and maturity at the time of transvaginal follicular aspiration

Forty-four consecutive patients undergoing transvaginal follicular aspiration for in vitro fertilization underwent ultrasonic measurement of follicular diameter at the time of oocyte retrieval to determine the correlation of follicular size with recovery rates and oocyte maturity. Based on the results of 412 follicles aspirated, the data were grouped by size (11, 12–14, 15–17, 18–20, and 21 mm) and oocyte maturity. Recovery rates were significantly higher in 18- to 20-mm follicles (P<0.01) and lower in those 11 mm (P<0.001). The probability of retrieving a metaphase I or II oocyte was significantly lower in follicles 11 mm (P<0.001), somewhat higher in 12- to 14-mm follicles (P<0.01), and equally high among the other groups. There were no differences in the incidence of fractured zonas. We conclude that follicles 15 mm provide the highest probability of retrieving mature oocytes and the low recovery rates of mature oocytes from follicles 11 mm suggest that, in selected circumstances, the operating surgeon may choose not to aspirate them.     

Human Embryos Derived from In Vitro and In Vivo Matured Oocytes: Analysis for Chromosomal Abnormalities and Nuclear Morphology

Purpose: To determine whether embryos resulting fromoocytes matured in vitro have a higher incidence of nuclearand/or genetic abnormalities compared to embryos resultingfrom oocytes matured in vivo. Methods: Fluorescence in situ hybridization analysis forchromosomes X, Y, and 18 was used to compare the ratesof aneuploidy, mosaicism, and nuclear abnormalities inembryos derived from oocytes that were prophase I ataspiration (immature group) to that observed in embryos resultingfrom oocytes that were metaphase I or II at aspiration(mature group). Results: Based on nuclear morphology, significantly moreembryos in the mature group (23percnt;) were classified as normalcompared to embryos in the immature group (3percnt;). Nodifference was found in the rate of aneuploidy or in the incidenceof mosaicism involving these chromosomes. Conclusions: These findings suggest that few embryosderived from prophase I oocytes collected following ovarianstimulation are morphologically normal.     

Isolation,in vitro maturation,and fertilization of germinal vesicle oocytes obtained from the intact murine ovary

The purpose of this investigation was to attempt to develop a process, utilizing a murine model, which would allow more efficient harvesting from the intact ovary and maturation in vitro of germinal vesicle (GV) oocytes. The recovery process yielded 25.5±4.5 ( ±SE) cumulusfree GV oocytes per animal. Treatment groups included culture medium (CM) supplemented with either estradiol (E₂), follicle stimulating hormone (FSH), human chorionic gonadotropin (hCG), or prolactin (PRL). Among the hormone-free controls 83.2±1.6% of oocytes underwent GV breakdown, whereas 25.3±2.6% developed to the first polar body stage (PB-1) following 18 hr of incubation (n=29 trials). Oocytes progressing to the PB-1 stage were inseminated in vitro. In vitro fertilization (IVF) of pooled in vitro matured (IVM) PB-1 oocytes (judged by two-cell formation) was 19.9%, which was significantly lower than in the group of in vivo matured oocytes (74.7%). E₂ significantly increased the percentage of GV breakdown (control, 76.8±2.5%; E₂ at 10 ng/ml, 92.9±2.5%,P<0.001; E₂ at 100 ng/ml, 93.7±2.1%,P<0.001; and E₂ at 1 g/ml, 86.7±3.3%,P<0.05) but not PB-1 formation. Neither FSH nor hCG significantly increased GV breakdown or PB-1 formation. Prolactin treatment resulted in an increased percentage of PB-1 formation (control, 25.3±2.5%; PRL at 2 g/ml, 35.0±2.9%; and PRL at 20 g/ml, 34.1±1.9%;P<0.01), fertilization (control, 15.3±5.1%; PRL, 33.6±8.5;P<0.01), and subsequent development (control, 3.5±2.3%; PRL, 18.8±5.6%;P<0.01). We conclude that recovery and IVM of GV oocytes is feasible, however, further work is necessary to define optimal conditions.     

Satellite in vitro fertilization: The Oregon experience

Objective: This study was designed to compare the results of preliminary evaluation, ovarian hyperstimulation, and monitoring of patients at a distant in vitro fertilization satellite center with those treated at the main campus of the program.Study design: Fifty-four patients completing oocyte retrieval cycles at the Eugene satellite Oregon Health Sciences University in vitro fertilization program for the period Jan. 1, 1991, through Dec. 31, 1993, were compared with 222 patients at the main campus for age, peak estradiol level, number of oocytes, retrieved, number of embryos, clinical pregnancy rate, and pregnancy outcome.Results: There were no statistically significant differences between the Eugene in vitro fertilization satellite center and the main campus for any of the factors analyzed with the exception of clinical pregnancy rate. The clinical pregnancy rate per cycle at the Eugene satellite center was 39% while the Portland main campus rate was 23% (p = 0.027), presumably because of a larger number of couples with severe male factor infertility at the central site.Conclusion: A distant in vitro fertilization satellite program was highly successful in the Oregon experience. In addition to greater convenience to the patients, the program was highly comparable to main campus program in measured parameters of ovarian hyperstimulation, oocyte retrieval, number of embryos, and pregnancy rate.     

GYNECOLOGY: Exposure of Human Oocytes to Endometrioma Fluid Does Not Alter Fertilization or Early Embryo Development

Background: Extensive endometriosis causes a mechanical disturbance in the pelvis leading to obstructive-type infertility. However, minimal or mild endometriosis is suspected to cause infertility, possibly through a humoral agent. Previous studies reported the presence of a factor in the serum of patients with endometriosis which reduced fertilization and early embryo formation in a rat IVF model.Methods: In the present article, we report a comparison of oocytes exposed to endometrioma fluid and oocytes not exposed (controls) in the context of a human IVF setting. We have been in the practice of aspirating oocytes into prewarmed 60-ml syringes containing culture medium. We have shown previously that this technique reduces the length of oocyte retrieval without compromising success. In 14 women undergoing oocyte retrieval, we inadvertently entered an endometrioma. This resulted in retrieved oocytes that were either exposed or not exposed to endometrioma fluid.Results: In contrast to previous reports, we found no difference in fertilization or early embryo development between the two groups. The fertilization rate for oocytes exposed to an endometrioma was 60%, versus 56% for controls. The good-quality embryo formation rate for oocytes exposed to an endometrioma was 45%, versus 46% for controls.     

Treatment variables in relation to oocyte maturation: Lessons from a clinical micromanipulation-assisted in vitro fertilization program

Objective: In an effort to understand the mechanism underlying the improved pregnancy rate observed in IVF cycles when gonadotropin-releasing hormone analogues (GnRH-a) are applied, we investigated a possible relationship between treatment variables and oocyte-nuclear maturity. Design: Nuclear maturity was retrospectively assessed in cumulus-free, denuded oocytes, obtained from women undergoing micromanipulation-assisted IVF treatment following controlled ovarian hyperstimulation with GnRH-a and menotropins. Setting: The setting was the infertility and IVF unit of a tertiary academic medical center. Participants: Two hundred twenty-one patients underwent 435 treatment cycles. Main Outcome Measure: This was the proportion of germinal vesicle-intact immature (GVII) oocytes. Results: One hundred fifty-four of the 3520 oocytes studied (4.4%) were in the GVII stage. These oocytes were found in 66 of the treatment cycles (15.2%) and in 54 of the patients (24.4%). Cycles in which GVII oocytes were detected did not differ from those in which all the aspirated oocytes were mature in the following respects: patient age, type and duration of infertility, controlled ovarian hyperstimulation protocol and time of ovum pickup. However, the GVII group was characterized by a significantly higher peak estradiol level, as well as a higher number of mature follicles visualized sonographically (diameter, >14 mm) and oocytes retrieved. Conclusions: Comparing the present findings with previously published data, it appears that the inclusion of GnRH-a in the stimulation regimen is associated with a lower proportion of immature oocytes. A higher occurrence of oocyte-nuclear immaturity is apparently associated with a significantly better ovarian response to stimulation. The high incidence of immature oocytes observed in patients with normospermic partners and low fertilization rates in previous cycles may suggest that the fertilization failure in some of these cases is due to oocyte, rather than sperm, dysfunction.     

Motile sperm organelle morphology examination (MSOME) can predict outcomes of conventional in vitro fertilization: A prospective pilot diagnostic study

The objective of this prospective diagnostic study was to explore the relationships between the morphological indices of sperm using motile sperm organelle morphology examination (MSOME) and the clinical outcome of in vitro fertilization (IVF). A total of 291 couples were included in this study. The female patients exhibited tubal and pelvic factors, and their partners’ gametes were tested prospectively by MSOME. Spearman correlation analysis was used to identify the relationship between MSOME and IVF rates and conventional sperm parameters. The effect of MSOME characteristics on pregnancy outcome was analyzed by multivariate logistic regression. MSOME characteristics showed statistical relationships with sperm concentration (R = 0.130, P = 0.025), progressive motility (R = 0.260, P < 0.001), and strict normal morphology (P = 0.648, R < 0.001). The percentage of sperm with normal morphology and vacuolation in the anterior head of the sperm, as observed by MSOME, was highly correlated with the IVF fertilization rate (R = 0.176, P = 0.002; P = ? 0.230, P < 0.001 respectively). The combined incidence of morphologically normal sperm and posterior vacuolation of the sperm head, as assessed by MSOME, was a predictor of clinical pregnancy (CP) after IVF (sensitivity, 92.9%; specificity, 42.47; and area under the ROC curve, 76.59%). The percentage of normal morphology of sperm by MSOME (OR 3.52, 95% CI 2.05–6.05, P < 0.001) and the posterior part vacuolated sperm (OR 0.65, 95% CI 0.52–0.82, P < 0.001) were significant predictors of successful CP. The MSOME index was significantly correlated with fertilization rates and CP after IVF, and testing with MSOME could constitute a valid diagnostic predictor of IVF outcome.     

Symmetry in number of retrieved oocytes between two ovaries: a possible predictor of in vitro fertilization outcome

Objective.?To examine the relationship between the ratio of difference in number of retrieved oocytes from the two ovaries to total number of oocytes (difference ratio, |N_RO?N_LO|/N_TOTAL) and in vitro fertilization (IVF) outcome.

Methods.?Retrospective review of medical record for infertility patients with intact two ovaries who had undertaken controlled ovarian stimulation (COS) and IVF cycles in Seoul National University Hospital was conducted. Characteristics and IVF outcomes were compared according to the difference ratio (|N_RO?N_LO|/N_TOTAL) using student t-test and χ² test. To adjust for the effect of confounding factors, binary logistic regression test was performed.

Results.?When the study population was divided according to the difference ratio by cut-off value of 0.4, patients with difference ratio less than 0.4 showed significantly higher pregnancy rate (25.7% vs. 17.1%, p?=?0.021). A significant correlation was noted between the difference ratio and achievement of pregnancy after adjustment for patient's age and total number of top quality embryos transferred (adjusted OR?=?0.40, 95% CI 0.19–0.83, p?=?0.014).

Conclusions.?The difference ratio of retrieved oocytes in patients with intact two ovaries was observed to have prognostic value in IVF cycles.     

Relationship of the Human Cumulus-Free Oocyte Maturational Profile with In Vitro Outcome Parameters After Intracytoplasmic Sperm Injection

Purpose: We investigated whether the human oocyte maturational profile at the removal of cumulus/corona cells affects the fertilization rate and subsequent embryo quality after intracytoplasmic sperm injection. Methods: A total of 1011 oocytes from 150 cycles was included in this retrospective analysis. Cumulus-free oocytes that were in prophase or metaphase I of meiosis at the removal of cumulus/corona cells were incubated in vitro until they reached metaphase II (in vitro-matured oocytes) and were then immediately injected with a single spermatozoa. Oocytes that were in metaphase II at the removal of cumulus/corona cells (MII oocytes) received sperm injection after 3–4 hr of preinjection incubation. Results: The fertilization rate of the MII oocytes was significantly higher than that of in vitro-matured oocytes (81 vs 62%; P < 0.001). The cleavage rates were similar in the two groups (MII oocytes, 94%; in vitro-matured oocytes, 91%). However, MII oocytes had significantly higher percentages of good-quality embryos (grade 1–3 embryos, 87 vs 58%, P < 0.001) and embryos with high cumulative embryo scores (score 10–32 embryos, 62 vs 33%, P < 0.001). The mean cumulative embryo score of MII oocytes after fertilization was also higher than that of in vitro-matured oocytes (12.1 ± 3.8 vs 8.8 ± 3.4; P = 0.014). Conclusions: MII oocytes that extruded the first polar body at the removal of cumulus/corona cells had better fertilization rates and embryo morphology than in vitro-matured oocytes that extruded the first polar body following the removal of cumulus/corona cells and in vitro culture.     

The effects of coculture with autologous cryopreserved endometrial cells on human in vitro fertilization and early embryo morphology: A randomized study

Purpose: The aim of this study was to examine the influence of endometrial cells on the fertilization rate and early embryonic morphology following routine in vitro fertilization (IVF). Cryopreservation with subsequent thawing allowed the use of autologous somatic cells, thus minimizing the risk of transmission of infective agents. Interpatient variability was eliminated by randomizing oocytes from each cycle into the control or coculture group. Results: Two hundred ninety-four oocytes from 24 IVF cycles (21 patients) were included in the study (145 coculture and 149 control). The normal fertilization rate of control oocytes (56.4%) was not significantly different from that of oocytes cocultured with endometrial cells (61.4%). The mean number of blastomeres in cocultured embryos (3.65) was not significantly different from the number in control embryos (3.46) 2 days after insemination, but the proportion of embryos with minimal or no fragmentation was significantly higher in the coculture group [34/84 (40.5%) vs.17/80 (21.3%);P<0.01]. Conclusions: The inclusion of cryopreserved autologous endometrial cells in routine clinical IVF procedures does not influence fertilization or the early cleavage rate but may reduce the extent of embryo fragmentation during the early cleavage divisions.     

Zona drilling: A new approach to male infertility

Conclusions and prospects Zona drilling is a powerful new tool for increasing the efficiency of IVF in animals and humans. The procedure incurs minimal harm to the oocyte and retains potentially selective prerequisites for sperm fertilizability such as motility. The methodology results in fertilization by sperm which have spontaneously undergone the AR, a situation which contrasts with normal fertilization. However, animal studies indicate that this feature does not compromise embryo development and, further, suggest that many potentially normal sperm are excluded from participating in fertilization by virtue of having undergone the AR. This observation not only reveals fundamental characteristics of normal fertilization, but offers encouragement that zona drilling can be used to increase the number of normal live births in both animal and human systems.In animals, reproductively compromised but otherwise highly valuable genotypes could be rescued by zona drillings. The method might also allow efficient fertilization in vitro in species for which this procedure is currently ineffective. In humans zona drilling clearly can allow previously infertile couples to become pregnant. It also may be useful in enhancing the fertilization rate for oocytes which must be reinseminated. In short, zona manipulation promises to fulfill an increasingly important role in reproductive management of humans and livestock.     

The successful recovery and fertilization of oocytes from the pouch of Douglas

Two groups of women were studied in whom a proportion of follicles had either ovulated spontaneously (7 women) or ruptured during manipulation at laparoscopy (30 women), and oocytes were recovered from the pouch of Douglas. There were no significant differences in the fertilization rates of oocytes collected in the pouch of Douglas from ovulated follicles, compared with those from the remaining intact follicles [15/20 (75%) vs 14/20 (70%)]. Also there was no significant difference between the fertilization rate of oocytes from follicles ruptured at the time of oocyte collection and that of oocytes from inlact follicles [25/38 (66%) vs 101/140 (72%)]. One woman became pregnant, following the transfer of four four-cell embryos, all derived from spontaneously ovulated oocytes found in the pouch of Douglas. She gave birth to a baby girl. The present study has shown that (1) oocytes may still be retrieved from the pouch of Douglas, despite follicle dispersal; (ii) these oocytes can be fertilized; and (iii) the embryos derived from ovulated oocytes recovered from the pouch of Douglas may generate an ongoing pregnancy following in vitro fertilization and embryo transfer.     

Embryo morphology score on day 3 is predictive of implantation and live birth rates

Purpose : To determine if embryo cleavage state or morphology on day 3 correlates with implantation or live birth rates. A retrospective cohort study of all fresh embryo transfers over 2 years. Methods : Patients were grouped by the average cleavage state and morphology. Cleavage state groups were: <6, ≥6, <8, and ≥8 cells. Morphology groups by average grade were: group 1 (best) = 1, group 2 = >1≤2, group 3 = >2≤3, and group 4 (worst) = >3≤4. Results : The overall implantation rate for 158 cycles was 28.1% with a live birth rate of 37.3%. Morphologic state was highly predictive of both implantation rate and live birth rate. Implantation rates by group were 54.8% (group 1), 30.4% (group 2), 23.8% (group 3), and 11.1% (group 4). Likewise, live birth rates among groups were 61.5, 39, 20, and 21%, respectively. Cleavage state was not predictive of outcome. Conclusions : Embryo grade is highly predictive of implantation and live birth rate and can be used to determine the number of embryos to transfer. Cleavage state is not predictive of outcome.     

Ovarian suppression with leuprolide acetate: Comparison of luteal,follicular, and flare-up administration in controlled ovarian hyperstimulation for oocyte retrieval

Adjunct use of leuprolide (LA) in patients undergoing controlled ovarian hyperstimulation with human menopausal gonadotropins (hMG) was evaluated by three protocols: Group F(n=24) began LA on day 2 of the cycle and Group L(n=38) began LA on day 23 of the cycle until ovarian suppression, at which time hMG was added. Group FL (n=17) began LA on day 1 and hMG on day 3. Compared to FL, more ova were collected, more ova fertilized, and more pregnancies resulted per initiated cycle in groups achieving suppression before hMG stimulation. Fewer days were necessary to attain suppression for L vs F. After achieving suppression, patients were maintained on either 0.5 mg LA or 0.25 mg LA daily during hMG coadministration with similar results. Lower maintenance doses of LA during hMG did not decrease the amount of hMG needed but retained the benefits of LA. We recommend luteal initiation of LA to achieve suppression before hMG.Presented in part at the 45th Annual Meeting of the American Fertility Society, San Francisco, California, November 1989.     

Simplification of the method of in vitro fertilization: Sonographic measurements of follicular diameter as the sole index of follicular maturity

As a simplification of the in vitro fertilization (IVF) procedure, repeated sonographic scanning of follicular diameters in stimulated cycles was performed, until the largest visible follicle reached a mean diameter of at least 28 mm, at which time human chorionic gonadotropin (hCG) was administered. Follicle puncture was performed either guided by sonography or by laparoscopy 34–36 hr after the hCG injection, and following insemination oocytes were cultured for 48–60 hr before embryo transfer (ET). Serum levels of luteinizing hormone (LH), prolactin (PRL), and estradiol-17 (E₂) at the time of hCG injection as well as follicular fluid levels of follicle stimulating hormone (FSH), LH, and PRL as well as progesterone (P), testosterone (T), and E₂ at the time of puncture were determined in retrospect using specific radioimmunoassay (RIA). It was found that the knowledge of a single value of LH or E₂ in serum should have been of little additional value for the decision to give hCG in all stimulation models used: clomiphene+hCG, human menopausal gonadotropin (hMG)+hCG, and clomiphene+hMG+hCG. The concentrations of the three steroids measured in follicular fluid were, in a high proportion of the follicles, within a normal range in all stimulation models. The group receiving clomiphene+hMG+hCG appeared promising through its higher proportion of estrogenic follicles. It is concluded that sonographic measurement of follicular diameters may be used as the sole index of follicular maturity in an IVF program. In cases with more pronounced superovulation as may be obtained by hMG stimulation, serial E₂ analyses are required in addition in order to ensure a high proportion of estrogenic follicles and an optimal pregnancy rate.