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Thread: quality of eggs

  1. #1

    Default quality of eggs

    My husband and I have gone through 4 years of infertility with no success. We are now considering using donated frozen eggs. Dr. Shapiro in Atlanta has a study using a new way of freezing the eggs.

    My question is, is there evidence that freezing an egg causes harm to the baby? Or, is it really a matter of getting them to thaw and survive?


  2. #2
    Join Date
    Oct 2008

    Default Egg Freezing

    The issue is not to freeze them but which one is actually frozen. Please see below:

    - Vol 17. No 4. 2008 524-529 Reproductive BioMedicine Online; on web 19 August 2008
    Selective vitrification of euploid oocytes markedly improves survival, fertilization and pregnancy-generating potential
    Dr Geoffrey Sher is a Fellow of the Royal College of Obstetrics and Gynaecology, a Fellow of the American College of Obstetrics and is qualified in Maternal and Fetal Medicine as a subspeciality. He is founder and Executive Medical Director of the Sher Institutes for Reproductive Medicine (SIRM) and is Clinical Professor of Obstetrics and Gynecology at the University Of Nevada School of Medicine. His research interests centre around factors that influence implantation following IVF, including: the role of ultrasound in the evaluation of oestrogen-induced endometrial proliferation, immunological factors and immunotherapy in IVF, and the role of HLA-G and the cytokine network in embryo–endometrial interaction.
    Dr Geoffrey Sher
    G Sher1,2,6, L Keskintepe1, T Mukaida3, M Keskintepe4, M Ginsburg4, Y Agca5, G Maassarani1, A Bayrak1
    Sher Institutes for Reproductive Medicine; 2Department of Obstetrics and Gynecology, University of Nevada School of Medicine, Reno, NV, USA; 3Hart Institute, Hiroshima, Japan; 4ReproCure LLC; 5Pathobiology Department, University of Missouri, MO, USA
    6Correspondence: Sher Institute for Reproductive Medicine, Las Vegas, 3121 S Maryland Parkway, Suite 300, Las Vegas, NV 89109, USA. Tel: +1 702 8929696; Fax: +1 702 8929666; e-mail:
    Enthusiasm for oocyte cryopreservation has been limited by poor pregnancy rates per thawed metaphase II (MII) oocytes (<4%) and low implantation rates per embryos. The reasons relate to technical limitations in the freezing process, and the fact that <40% of oocytes are euploid and unable to produce ‘competent’ embryos. Comparative genomic hybridization was performed on the first polar body (PB-1) of 323 MII oocytes retrieved from 16 donors. Of these, 111 were euploid, and were vitrified. Seventy-five of 78 vitrified oocytes (96%) survived warming and were fertilized using intracytoplasmic sperm injection. Thirty-one (41%) subsequently developed into expanded blastocysts, of which no more than two were subsequently transferred per uterus to 16 out of 19 prospective embryo recipients. Twelve of 19 (63%) recipients produced 17 healthy babies (eight singletons, three twins, and one set of triplets) One twin pregnancy miscarried in the late first trimester The birth rate per transfer of a maximum of two blastocysts to 16 recipients was 75%. The implantation rate per vitrified euploid oocyte was 27%. This study showed a six-fold improvement in pregnancy rate per cryopreserved oocyte over previous reports and a marked improvement in implantation rate. If independently validated, this approach could open the door to commercial egg cryobanking, significantly expanding women’s reproductive choices.
    Keywords: CGH, implantation, oocyte, pregnancy, vitrification
    In 1986, Chen reported the first pregnancy resulting from the transfer of embryos derived from previously cryopreserved oocytes (Chen, 1986). Since then, fewer than 350 births have been recorded in the scientific literature, although recent reports have been more encouraging (Isachenko et al., 2005; Kuwayama et al., 2005).
    The success of human oocyte freezing is a function of the method of cryopreservation used and the ‘quality’ of the eggs selected. In the last few years, ultra-rapid embryo/oocyte vitrification has all but supplanted the conventional methods of cryopreservation. This has resulted in a significant improvement in post-thaw/warming oocyte survival and viability, as well as subsequent fertilization and pregnancy potential following embryo transfer (Kulleshova and Lopata, 2002; Kuwayama, 2007). Despite such enhancements, the highest reported pregnancy rate achieved per cryopreserved oocyte after fertilization and embryo transfer has been approximately 4% (Coticchio et al., 2007), thereby rendering the widespread introduction and/or commercialization of oocyte cryobanking both impractical and inadvisable.
    © 2008 Published by Reproductive Healthcare Ltd, Duck End Farm, Dry Drayton, Cambridge CB3 8DB, UK
    It has recently been shown that approximately 60% of oocytes and embryos are aneuploid. These ‘incompetent’ oocytes are incapable of propagating healthy pregnancies, in addition to being far less likely to survive the cryopreservation process (Sher et al., 2007b). In a previous study, full karyotyping of pre- and post-fertilized oocytes and embryos was performed using comparative genomic hybridization (CGH) performed on the first and second polar bodies (PB-1 and 2) biopsied from pre- and post-fertilized oocytes and blastomeres (day-3 embryos). The findings revealed that in young fertile women under age of 34, only 35% of mature metaphase II (MII) oocytes were euploid; >90% of euploid post-fertilized oocytes spawned euploid zygotes and embryos; 100% of aneuploid oocytes propagated aneuploid embryos; and embryos that failed to develop to the blastocyst stage were aneuploid in >95% of cases.
    The present Western Institutional Review Board (WIRB)-
    approved study evaluated IVF outcome reported as implantation rates and live birth rates following the selective transfer of no more than two blastocysts derived through fertilization of previously vitrified euploid donor oocytes.
    Materials and methods
    Ovum donor recruitment
    Sixteen oocyte donors under 35 years of age (mean ± SD = 29.4 ± 4.3) were recruited to this study between January 2006 and July 2007. After screening all oocyte donors for any significant medical, surgical and family history, they subsequently underwent comprehensive physical examinations and standard Food and Drug Administration-required laboratory testing that assessed for the presence of substance abuse, genetic diseases and sexually transmittable infections.
    Ovarian stimulation, oocyte retrieval and polar body biopsy
    Polar body biopsy and vitrification were completed in 3 h after oocyte retrieval. Following appropriate disclosure, each donor underwent ovarian stimulation as previously described (Fisch et al., 2007). Human chorionic gonadotrophin (HCG), 10,000 IU (Profasi; Organon Pharmaceuticals, USA) was used to trigger ovulation in all cases. Oocyte retrieval was performed 34–37 h later using a transvaginal sonogram-guided needle. Conscious sedation was induced with intravenous Propofol. The surrounding cumulus oophorus was stripped from each oocyte and polar body biopsy was performed on all MII oocytes as previously described (Sher et al., 2007a,b). MII oocytes were then individually vitrified using the cryoloop system (detailed below). Oocyte donor demographics and clinical criteria are presented in Table 1.
    Comparative genomic hybridization (CGH)
    Comparative genomic hybridization (CGH) for polar bodies was performed as described elsewhere (Sher et al., 2007b).
    Vitrification of MII oocytes
    MII oocytes were kept at 37°C in modified human tubal fluid medium (mHTF; IVF Online, USA) supplemented with 10% synthetic serum supplement for 10–30 min until vitrification was conducted. MII oocytes were consecutively placed in different aliquots of vitrification media (VM), each comprising mHTF with a different concentration of dimethyl sulphoxide (DMSO) (2, 4, 6, 8, 10%) and ethylene glycol (2, 4, 6, 8, 10%) for 30, 30, 60, 60 and 90 s respectively. Finally, each MII oocyte was transferred to VM comprising mHTF + 20% DMSO + 20% ethylene glycol + 1 mol/l sucrose + 0.1 mol/l Ficoll for 30 s, and then placed on a 0.5 μm cryoloop. The latter was plunged directly into liquid nitrogen (−196°C) and placed in a 1-ml plastic vial for storage.
    Oocyte warming
    Individual cryoloops were removed from their plastic vials and plunged into media containing 1.5 mol/l sucrose at 37°C for 50 s, and then sequentially placed in sucrose, 1.0, 0.75, 0.5, 0.25, 0.125 and 0.0 mol/l respectively, for 0.5–2 min in each concentration at 37°C.
    Oocyte fertilization and embryo transfer
    Progesterone injections were initiated 6 days prior to intended embryo transfer, and vitrified oocytes were sequentially warmed one at a time until a total of three viable MII oocytes were available. Once oocytes were warmed and viability confirmed, they were kept in culture for 2 h prior to intracytoplasmic sperm injection (ICSI). All oocytes were cultured individually in 50 μl of Global One media (IVF online) and the drop covered with mineral oil. Cleaved embryos were individually cultured to the blastocyst stage in Global One medium at 37°C, in an environment of 6% CO2, 5% O2, 89% nitrogen and 95% humidity. Only those embryos that had developed to the expanded blastocyst stage by day 5 or 6 post-ICSI and exhibited well-developed inner cell masses and trophectoderms were deemed eligible for embryo transfer.
    Article - Vitrification of euploid oocytes improves outcomes -
    G Sher et al.

    Table 1. Comparative genomic hybridization (CGH) results from first polar body biopsies performed on oocytes from 13 ovum donors.
    Parameter Value
    Mean donor age in years ± SD 26.6 ± 4.4
    No. of MII oocytes obtained 323
    Mean no. of MII oocytes/donor ± SD 20.1 ± 8.3
    CGH-normal oocyte
    n (%) 111 (34)
    CGH-abnormal oocyte
    n (%) 191 (59)
    CGH-equivocal oocytes
    a n (%) 21 (7)
    aPloidy undetermined.
    Recruitment and preparation of embryo recipients
    Nineteen embryo recipients were admitted to the study and all were treated free of charge. Only menopausal women and women with depleted or severely diminished ovarian reserve, as defined by a cycle day 3 FSH concentration of >15 mIU/ml in association with a plasma oestradiol concentration of <70 pg/ml and a past history of a poor ovarian response to ovarian stimulation (i.e. the production of ≤3 follicles following ovarian stimulation with >600 IU of FSH daily), were deemed eligible for participation in this study. Admittance was subject to physical and emotional criteria, which were determined through a detailed medical history, physical and psychological examinations, electrocardiogram and laboratory testing of both prospective parents. Full disclosure was made to all recipient couples, who were also counselled and then required to sign a written consent form. Table 2 presents the demographic and clinical characteristics pertaining to the 19 embryo recipients whose ages ranged from 38 to 45 years (mean age 38.4 ± 3.6). All women had normal uterine cavities as assessed by preceding sonohysterography or hysteroscopy and had preceding ultrasound evidence of endometrial linings that measured ≥9 mm around the time of spontaneous or induced ovulation.
    Hormonal treatment of recipients
    An oestradiol valerate injection (4–8 mg) i.m. was administered every 3 days, starting with the onset of birth control pill-induced menstruation, until the plasma oestradiol concentration was stabilized. The goal of stabilizing the plasma oestradiol concentration at 500–1000 pg/ml in association with an endometrial thickness of ≥9 mm was achieved within 8–12 days in all cases. Subsequently, daily i.m. injections of 100 mg progesterone in oil were initiated. At the same time, pre-vitrified oocytes were warmed so as to obtain three viable oocytes available for ICSI using partner, or designated donor, spermatozoa. The fertilized oocytes were cultured for up to 6 days as previously described above.
    Embryo transfer
    Subject to patient choice and availability, no more than two blastocysts were transferred in each case. Supernumerary blastocysts were re-vitrified and cryobanked for future use at the sole discretion of the designated recipient and her partner. Embryo transfers were performed on day 6 of administration (day 5 of embryo development to the blastocyst stage). In the event of pregnancy, the prescribed oestrogen/progesterone regime was continued to week 10 of gestation. In all cases where pregnancy did not occur, or failed to survive, hormonal treatment was immediately stopped.
    Statistical analysis
    Differences between groups were evaluated with Student’s t-test. Differences in rates and proportions among groups were evaluated by chi-squared tests and Fisher’s exact test where appropriate. Significance was set at P < 0.05.
    Article - Vitrification of euploid oocytes improves outcomes - G Sher et al.
    Table 2. Outcome of the transfer of blastocysts derived from the fertilization of warmed, previtrified euploid oocytes.
    Parameter Value
    Prospective embryo recipients 19
    Actual embryo recipients (i.e. no. of embryo transfers) 16
    Mean recipient age in years ± SD 38.4 ± 3.6
    Oocytes vitrified 111
    Oocytes warmed 78
    Oocytes that survived warming (%) 75 (96)
    Cleaved embryos (%) 57 (76)
    Blastocysts (%) 37 (65)
    Blastocysts transferred 31
    Blastocysts cryobanked (supernumerary) 6
    Mean no. of blastocysts/embryo transfer ± SD 1.6 ± 0.4
    Births/embryo transfer(%) 12/16 (75)
    Births/woman (%) 12/19 (63)
    Implantation rate/blastocyst (%) 19/31(61)
    Implantation rate per warmed euploid oocyte (%) 19/72
    a (26)
    Full-term pregnancies 12
    Singletons 8
    Twins 3
    Triplets 1
    Miscarriages 1
    aSix supernumerary blastocysts of those derived from 78 vitrified/warmed oocytes were revitrified.

    Table 1 depicts the outcome of PB-1 CGH analysis of 323 mature (MII) previtrified/warmed oocytes (MII) obtained from 16 egg donors. A total of 111 (34%) were found to be euploid. Seventy-eight of these (70%) were subsequently warmed in preparation for ICSI, of which 75 (96%) survived the warming process, and 68 (91%) subsequently fertilized as shown by the development of two pronuclei within 16–18 h following ICSI. Fifty-seven (85%) of 67 viable warmed oocytes developed into cleaved embryos, of which 37 (65%) developed to the expanded and well differentiated blastocyst stage. Sixteen of 19 (84%) potential recipients underwent embryo transfer with no more than two blastocysts (mean = 1.2 ± 0.6). In three cases (16%), due to incompatibility in oocyte/recipient match, no viable blastocysts were generated for embryo transfer and in six cases at least one supernumerary embryo was re-vitrified and banked for future use by the designated couple. Twelve of the 19 (63%) potential recipients and 12 of the 16 women (75%) who underwent embryo transfer achieved live births. There were eight singleton pregnancies (67%), three (25%) sets of twins, and one (8%) triplet pregnancy. The implantation rate per blastocyst transfer was 61% (19/31). The transfer of 31/37 blastocysts derived from 78 warmed oocytes (six supernumerary blastocysts were cryobanked) resulted in 17 babies born and two concepti (twins) lost through one first trimester miscarriage, for an implantation rate per warmed, euploid oocyte of 27% (19/71).
    Table 3 compares vitrified oocytes identified as euploid and aneuploid, and fresh donor oocytes that were collected during the study period. Euploid oocytes exhibited a higher survival rate (96%) than aneuploid oocytes (83%). Fertilization (by ICSI) rates were 93% (67/72) for vitrified euploid oocytes, 76% (47/62) for vitrified aneuploid oocytes and 87% (109/126) for fresh donor oocytes. In the euploid vitrified group, 1% of oocytes underwent abnormal fertilization 18 h after ICSI, whereas for aneuploid oocytes and fresh donor oocytes abnormal fertilization rates were 8 and 4% respectively. The cleavage rates on days 2 and 3 were better in vitrified euploid oocytes (85%) and fresh donor oocytes (92%) than in vitrified aneuploid oocytes (28%). Blastocyst development rates were similar (65 and 56%) for vitrified euploid oocytes and fresh donor oocytes, but superior to vitrified aneuploid oocytes (39%).
    Hitherto, results using cryopreserved oocytes have been rather disappointing (Boldt et al., 2006). Reported oocyte survival rates per cryopreserved MII oocyte range from 60 to 85%, fertilization rates from 62 to 87%, and implantation rates per embryo from 13.6 to 27% (Boldt et al., 2006; Coticchio et al., 2007; De Santis et al., 2007; Gook and Edgar, 2007). Even more alarming is the fact that the reported potential of a cryopreserved MII oocyte to survive thawing/warming with the ability to fertilize and, following embryo transfer, to be able to propagate a viable pregnancy is only about 4% (Coticchio et al., 2007). Such statistics have heretofore made the recommendation of oocyte cryobanking to women seeking fertility preservation both injudicious and disingenuous.
    The results reported in this study represent a six-fold improvement in the implantation rate per cryopreserved euploid MII oocyte. If corroborated through independent studies, these findings could open the door to widespread egg banking for fertility preservation and in the process, significantly expand the reproductive choices available to women. This will also be of obvious benefit to the thousands of women requiring treatments such as ovarian surgery, radiation, or chemotherapy, which often irreparably compromise oocyte viability. Reliable oocyte banking would also present the opportunity to temporarily store oocytes as a back-up option in case certain unforeseen problems arise during an IVF cycle, such as an absence or paucity of viable spermatozoa. In addition, the cryopreservation of pre-fertilized oocytes avoids the ethical concerns some patients may have with regard to the cryopreservation of embryos
    It is important to mention that mature human oocytes have great heterogeneity in the distribution and organization of cytoplasmic organelles and demonstrate considerable variability in membrane water permeability. Both of these characteristics
    can profoundly influence their viability and ‘competence’, as
    Article - Vitrification of euploid oocytes improves outcomes -
    G Sher et al.

    Table 3. Vitrified/warmed oocyte distribution, survival, fertilization and developmental competence by ploidy.
    Parameter Euploid Aneuploid FDO1 P-value
    Oocyte donors 13 13 13 –
    Mean donor age in years ± SD 26.6 ± 4.4 26.6 ± 4.4 25.8 ± 5.2 –
    Metaphase II oocytes warmed 75 75 −

    Survival (%) 72 (96)a 62 (83)b 0.05
    Normal fertilization (%) 67 (93) 47 (76) 109/126 (87) –
    Abnormal fertilization (%) 1 (1)
    c 5 (8)d 5 (4)c 0.05
    Degenerated oocytes (%) 1 (1) 2 (3) 2 (2) –
    Cleaved embryos (%) 57 (85)
    e 13 (28)f 100 (92)g 0.03
    Blastocysts (%) 37 (65)h 5 (39)i 56 (56)h 0.05
    a–iIn each row, different superscript letters denote statistically significant differences; 1FDO = fresh donor oocytes that were collected and injected during the same time period; no comparative genomic hybridization was performed on these.
    well as the success of the oocyte cryopreservation process. When compared with other cell varieties, the oocyte, because of its spherical shape, has the lowest surface area-to-volume ratio (Wright et al., 2004). Oocytes also have reduced permeability to cryoprotective additives (CPA) as compared with zygotes and embryos (Jackowski et al., 1980). Zech et al. (2005) demonstrated that the creation of an opening in the zona pellucida of human blastocysts prior to vitrification improved cryopreservation. They suggested that vitrifying partially or completely hatched blastocysts enhances the embryo cryopreservation process. It may also be possible that biopsied embryos with openings in the zona pellucida could be more vulnerable to stress induced by conventional cryopreservation (Joris et al., 1999; Magli et al., 1999).
    Oocyte cytoskeletal damage induced by increases in
    intracellular solute concentration along with intracellular ice formation represent the main reasons for cell damage during cryopreservation, and are more likely to occur with ‘conventional’ freezing (Borini et al., 2007). Ice formation (the more detrimental factor) can in large part be avoided by reducing intracellular water content by inducing cell dehydration. The recent introduction of ultra-rapid vitrification of both oocytes and embryos has yielded much improved results (Mukaida et al., 2003, 2006; Takahashi et al., 2005). With vitrification, the concentration of cryoprotectant is sufficient to prevent crystallization such that both ice and rising solute concentrations are avoided. However, one of the dangers of the vitrification process is that the very high concentration of cryoprotectant required can damage the oocyte (Coticchio et al., 2007). It is for this reason that regulation of both the introduction and removal of cryoprotectant, as well as the maintenance of an optimal temperature, is critical to the efficacy and safety of the process. The required concentration can be achieved through very rapid cooling and even more rapid warming (Gook and Edgar, 2007). The creation of an artificial slit at the zona pellucida during oocyte and/or embryo biopsy might in fact accelerate and improve subzonal dispersion of cryoprotectants at 37°C, as demonstrated for human blastocyst (Hiraoka et al., 2007; Ge et al., 2008). Recent reports (Kuwayama et al., 2005; Antinori et al., 2007; Cobo et al., 2008) have confirmed prior reports that vitrified oocytes have an improved survival rate as compared with conventionally frozen oocytes, and that overall pregnancy rates are likewise higher. The implantation rates reported in the literature with unselected vitrified oocytes range from 11 to 13% (Kuwayama et al., 2005; Antinori et al., 2007), whereas the present study reports 26% implantation rate with CGH-selected vitrified/warmed oocytes.
    A previous study has reported on the ability to fully karyotype
    all 23 chromosomes in the mature MII oocyte through the performance of CGH on the PB-1. It also reported that it is possible with 95% confidence to recognize euploid blastocysts based on the oocyte of origin being euploid.
    In the present study, the fertilization rate of vitrified/warmed euploid oocytes (93%) was comparable with fresh donor oocytes (87%), and superior to vitrified aneuploid oocytes (76%). However, the blastocyst development rate was better in vitrified euploid oocytes (65%) and fresh donor oocytes (56%) than vitrified aneuploid oocytes (39%).
    This study reports a 61% implantation rate per transferred
    blastocyst derived from fertilized, warmed euploid oocytes. While this represents a major improvement over prior reported results, it is nevertheless much lower than the 80% rate previously reported for blastocysts derived from fresh (non-precryopreserved) euploid oocytes (Sher et al., 2007a). It is concluded that while oocyte vitrification is much less traumatic than previous methods of cryopreservation, it still exacts a measurable toll on egg/embryo viability. The embryo implantation rates and live birth rates per oocyte in this study are considerably higher than any other method or study reported in the literature, so far as is known. The improved success rates reported in this study may be attributed to two factors: (i) identification through PB-1 CGH of euploid oocytes; and (ii) the use of ultra-rapid vitrification.
    While this preliminary report makes a strong case for selectively vitrifying and storing euploid oocytes for fertility preservation, for the time being it should not supplant the vitrification of euploid embryos derived through conventional IVF.
    Antinori M, Licata E, Dani G et al. 2007 Cryotop vitrification of human oocytes results in high survival rate and healthy deliveries. Reproductive BioMedicine Online 14, 72–79.
    Boldt J, Tidswell N, Sayers A
    et al. 2006 Human oocyte cryopreservation: 5-year experience with a sodium-depleted slow freezing method. Reproductive BioMedicine Online 13, 96–100.
    Borini A, Bianchi V, Bonu MA
    et al. 2007 Evidence-based clinical outcome of oocyte slow cooling. Reproductive BioMedicine Online 15, 175–181.
    Chen C 1986 Pregnancy after human oocyte cryopreservation.
    Lancet 1, 884–886.
    Cobo A, Kuwayama M, Pérez
    et al. 2008 Comparison of concomitant outcome achieved with fresh and cryopreserved donor oocytes vitrified by the Cryotop method. Fertility and Sterility 89, 1657–1664.
    Coticchio G, Bonu MA, Sciajno R
    et al. 2007 Truths and myths of oocyte sensitivity to controlled rate freezing. Reproductive BioMedicine Online 15, 24–30.
    De Santis L, Cino I, Coticchio G et al. 2007 Objective evaluation of the viability of cryopreserved oocytes. Reproductive BioMedicine Online 15, 338–345.
    Fisch JD, Keskintepe L, Ginsburg M
    et al. 2007 Graduated Embryo Score and soluble human leukocyte antigen-G expression improve assisted reproductive technology outcomes and suggest a basis for elective single-embryo transfer. Fertility and Sterility 87, 757–763.
    Ge HS, Zhou R, Zhang W, Lin JJ 2008 Impact of assisted hatching
    on fresh and frozen–thawed embryos: a prospective, randomized study. Reproductive BioMedicine Online 16, 589–596.
    Gook DA, Edgar DH 2007 Human oocyte cryopreservation.
    Human Reproduction Update 13, 591–605.
    Hiraoka K, Fuchiwaki M, Hiraoka K et al. 2007 Zona pellucida removal and vitrified blastocyst transfer outcome: a preliminary study Reproductive BioMedicine Online 15, 68–75.
    Isachenko V, Montag M, Isachenko E et al. 2005 Aseptic technology of vitrification of human pronuclear oocytes using open-pulled straws. Human Reproduction 20, 492–496.
    Jackowski S, Leibo SP, Maxur P 1980 Glycerol permeabilities of
    fertilized and infertilized mouse ova. Journal of Experimental Zoology 212, 329–341.
    Joris H, Van den Abbeel E, Vos AD, Van Steirteghem A 1999 Reduced survival after human embryo biopsy and subsequent
    cryopreservation. Human Reproduction 14, 2833–2837.
    Kuleshova LL, Lopata A 2002 Vitrification can be more favorable than
    slow cooling. Fertility and Sterility 78, 449–454.
    Kuwayama M 2007 Highly efficient vitrification for cryopreservation
    of human oocytes and embryos: the Cryotop method.
    Article - Vitrification of euploid oocytes improves outcomes - G Sher et al.

    Theriogenology 1, 73–80.
    Kuwayama M, Vajta G, Ieda S, Kato O 2005 Comparison of open and closed methods for vitrification of human embryos and the
    elimination of potential contamination. Reproductive BioMedicine Online 11, 608–614.
    Magli MC, Gianaroli L, Fortini D et al. 1999 Impact of blastomere biopsy and cryopreservation techniques on human embryo viability. Human Reproduction 14, 770–773.
    Mukaida T, Oka C, Goto T, Takahashi K 2006 Artificial shrinkage of blastocoeles using either a micro-needle or a laser pulse prior to the cooling steps of vitrification improves survival rate and pregnancy outcome of vitrified human blastocysts.
    Human Reproduction 21, 3246–3252.
    Mukaida T, Takahashi K, Kasai M 2003 Blastocyst cryopreservation: ultrarapid vitrification using cryoloop technique. Reproductive BioMedicine Online 6, 221–225.
    Sher G, Keskintepe L, Mukaida T
    et al. 2007a Selective vitrification of euploid oocytes markedly improves their post-warming viability and post-fertilization pregnancy generating potential, thereby opening the door to commercial egg banking. Fertility and Sterility 88, S343.
    Sher G, Keskintepe L, Keskintepe M
    et al. 2007b Oocyte karyotyping by comparative genomic hybridization provides a highly reliable method for selecting ‘competent’ embryos, markedly improving in vitro fertilization outcome: a multiphase study. Fertility and Sterility 87, 1033–1040.
    Takahashi K, Mukaida T, Goto T, Oka C 2005 Perinatal outcome of blastocyst transfer with vitrification using cryoloop: a 4-year follow-up study.
    Fertility and Sterility 84, 88–92.
    Wright VC, Schieve LA, Reynolds MA
    et al. 2004 Assisted reproductive technology surveillance. MMWR Surveillance Summaries 30, 1–20.
    Zech NH, Lejeune B, Zech H, Vanderzwalmen P 2005 Vitrification of
    hatching and hatched human blastocysts: effect of an opening in the zona pellucida before vitrification. Reproductive BioMedicine Online 11, 355–361.
    Declaration: The authors report no financial or commercial conflicts of interest.
    Received 1 February 2008; refereed 21 February 2008; accepted 30 May 2008.
    Article - Vitrification of euploid oocytes improves outcomes -
    G Sher et al.


  3. #3

    Default one more...

    So, is there evidence that the freezing process effects the ability of the egg to mature, implant and go to full term?

    do you think RBA's study is worth participating in or too soon to tell?

    Thanks again.

  4. #4
    Join Date
    Oct 2008

    Default Egg Freezing

    Freezing process, yes. But more importantly you need to know if the egg that was frozen is normal gnetically. The chance of having a normal egg at 25 is only 30%. So if they sell eggs, they need to guarantee that is a normal one. Otherwise, not worth it.

  5. #5
    Join Date
    Jun 2009

    Cool Choosing the donors

    I am new to the forum (done a lot of reading), but I do have one question; Is there a criteria for choosing the egg donors other than medical hx. Things like: build, eye color, hair color, shade, nationality.....? I know this can not be an exact but how does it work?

  6. #6
    Join Date
    Oct 2008


    I advise you chose an ED with the following criteria:
    1. Less than 25 y.o
    2. One previous IVF is a plus because I can obtain the IVF records and assess egg quality
    3. No more than 3 IVF as the egg quality is affected
    4. No IVF within the last 3 mo.
    Hope that helps. Please do not hesitate to contact me for any additional questions.

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