Polar Body Biopsy Research Articles

High follicle-stimulating hormone increases aneuploidy in human oocytes matured in vitro

To study the effect of FSH on the aneuploidy risk of human oocytes matured in vitro. Prospective study. Hospital-based IVF center. Patients with male factor infertility undergoing intracytoplasmic sperm injection (ICSI) cycles. Immature oocytes were put into five groups according to the FSH concentration (0, 5.5, 22, 100, and 2,000 ng/mL) in in vitro maturation (IVM) medium. Spindles were observed under a polarized microscope before polar body biopsy. Fixed polar bodies and corresponding oocytes were examined on chromosomes 13, 16, 18, 21, and 22 by fluorescence in situ hybridization. Oocytes matured in 5.5 and 2,000 ng/mL FSH were immunostained for tubulin and chromatin. Aneuploidy rate, spindle visualization rate, and spindle morphology. The frequency rates of aneuploidy were 26.7%, 23.3%, 36.75%, 46.67%, and 63.3% in the five FSH groups, respectively. There was a significantly higher aneuploidy rate in oocytes matured in the 2,000 ng/mL FSH group. The spindle visualization rates assessed under PolScope were not significantly different between aneuploid and normal oocytes. There was no difference in spindle morphology between the 2,000 and 5.5 ng/mL FSH groups. High-concentration FSH in IVM medium significantly increased the first meiotic division error, resulting in more aneuploid oocytes during IVM.

Preimplantation Genetic Diagnosis and Selection

The availability of assisted reproductive technologies and advances in molecular biology gave rise to preimplantation genetic diagnosis (PGD). PGD is an early form of prenatal diagnosis and determines the genotype of an embryo before implantation takes place to avoid the implantation of diseased embryos. This requires couples to adhere to a strict family planning and effective contraceptive strategy, and undergo in vitro fertilization (IVF) treatment. During IVF, sampling of the cells can be performed at different developmental stages from polar body biopsy to trophectoderm cells from the blastocysts. It is indicated in couples with a family history of monogenic autosomal or X-linked recessive or dominant disorders and in detecting chromosomal aberrations of the embryos. The genetic diagnosis is performed using appropriate molecular testing which might include polymerase chain reaction, fluorescent in situ hybridization, comparative genomic hybridization or microarrays. PGD is now a well-established procedure and offers an alternative reproductive choice for couples who are at risk of an affected child. In this review, the past, present and future aspect of PGD will be covered.

Are zona pellucida laser drilling and polar body biopsy safe for in vitro matured oocytes?

Preconception diagnosis requires first polar body biopsy. When the hole in the zona pellucida is made with a laser beam, heat propagation could, like the biopsy itself, be deleterious. Our aim was to evaluate the effect of this technique on human in vitro matured oocyte and embryo development. One hunded fifty five retrieved immature oocytes from 75 women, matured in vitro, were distributed in 3 groups: 50 oocytes in a control group, without laser drilling and first polar body biopsy, 52 oocytes in a group with only laser drilling, and 53 oocytes in a group with both laser drilling and first polar body biopsy. Safety was evaluated using four criteria: [1] oocyte lysis rate, [2] oocyte activation rate, [3] oocyte development after calcium ionophore treatment, [4] and embryo chromosome breakage incidence after Tarkowski preparation. No difference in the four criteria was observed between the 3 oocyte groups. We did not find evidence of deleterious effect of laser drilling and first polar body biopsy on in vitro matured oocytes, according to our criteria.

O5 PGS by polar body biopsy – High aneuploidy rate independent of age

O5 PGS by polar body biopsy – High aneuploidy rate independent of age

C28 PGD for aneuploidy: CGH

not available at time of publication. C28 PGD for aneuploidy: CGH L. Gianaroli1, M.C. Magli1, A.P. Ferraretti1, L. Muzii1, A.M. Crivello2, I. Stanghellini1. 1SISMER, Reproductive Medicine Unit, Bologna, Italy, 2Istituto di Ricerca Biomedica del Mediteraneo, Palermo, Italy *E-mail: luca.gianaroli@sismer.it (L. Gianaroli) The microarray technology has recently entered CGH allowing for the analysis of the full set of 23 pairs of chromosomes in a few hours without the need for embryo cryopreservation. Because this is a new form of screening and has only been used in a small number of cases, it is not yet possible to say how successful and reliable it is. A novel study has been organized by ESHRE PGS Task Force [1] with the end point of defining the efficiency and reliability of this technique. The initial standardization phase implied a pilot study in which specific objectives included (1) completing the analysis within a time period that allows for fresh transfer, and (2) ensuring the reliable identification of the chromosomal status of an oocyte in at least 90% of polar body biopsy attempts. The experimental phase included the biopsy of approximately 300 oocytes fertilized after ICSI from which, expecting a 50% aneuploidy rate, another 150 aneuploid oocytes would be processed for array analysis to verify the data obtained from the polar bodies. The study started in October 2009 in two selected centers (SISMER, Bologna Italy and University of Bonn, Germany) having proven experience in the technique of polar body biopsy. The acquisition of the data from the intended number of biopsied oocytes will be terminated by the end of March 2010. The images of the arrays were scored by two independent observers in each centre. To estimate the concordance of the data from the polar bodies and the corresponding oocytes, there was a blind analysis of those oocytes which were assessed as aneuploid based on the result of the chromosomal analysis of their polar bodies. According to the established protocol, the oocytes destined to be analyzed were amplified in the center where they had been generated and the amplified product was shipped to the other center where labelling, hybridization and analysis were performed in a totally blind manner. It was decision of each center to analyze also oocytes in which the polar body testing was inconclusive. All data will be evaluated by an independent data analysis team (University of Amsterdam). The concordance analysis will be made on the basis of the categories euploid/aneuploid/unknown with the aim of having at least 90% concordance. If the results from the pilot study fulfil the expected requirements, a multicentre randomized trial will follow to test the clinical validity of the technique.

What next for preimplantation genetic screening (PGS)? A position statement from the ESHRE PGD Consortium steering committee

Since 2004, there have been 11 randomized controlled trials (RCTs) mainly for advanced maternal age (AMA), which have shown no benefit of performing preimplantation genetic screening (PGS). Ten of the RCTs have been performed at the cleavage stage and one at the blastocyst stage. It is probable that the high levels of chromosomal mosaicism at cleavage stages, which may result in the tested cell not being representative of the embryo, and the inability to examine all of the chromosomes using fluorescence in situ hybridization, have contributed to the lack of positive outcome from the RCTs. We suggest that future RCTs should examine alternative biopsy timing (polar body and/or trophectoderm biopsy), and should apply technologies that allow more comprehensive testing to include all chromosomes (microarray-based testing) to determine if PGS shows an improvement in delivery rate. Currently there is no evidence that routine PGS is beneficial for patients with AMA and conclusive data (RCTs) on repeated miscarriage, implantation failure and severe male factor are missing. To evaluate benefits of PGS, an ESHRE trial has recently been started on patients with AMA using polar body biopsy and array-comparative genomic hybridization, which should bring more information on this patient group in the near future.

Live birth after polar body array comparative genomic hybridization prediction of embryo ploidy—the future of IVF?

To ascertain meiotic aneuploidy of the human egg using array comparative genomic hybridization to evaluate the 23-paired chromosome copy number of first polar body as an objective prognosticator of embryo viability for embryo transfer in the same cycle. Case report. Independent-sector IVF program. A 41-year-old woman with a history of 13 failed cycles of IVF. Polar body biopsy of metaphase II eggs. Birth. Two of the nine eggs were euploid, and the resulting embryos, although morphologically inferior to sibling embryos, were selected for transfer to the uterus, resulting in the birth of a normal healthy baby. Selection of euploid eggs, as an objective parameter of subsequent embryo viability and with the opportunity to transfer embryos in the same cycle could maximise the opportunity for live birth after IVF even in cases with poor prognosis.

Maternal age related effects on chromosome error in human oocytes

OBJECTIVE: Human chromosomes can be influenced at several stages during oogenesis with women who are at the end of their reproductive lifespan more susceptible to producing aneuploid oocytes. This study examined the impact of age on oocyte aneuploidy by evaluating 23 chromosomes following polar body (PB) biopsy. DESIGN: Retrospective analysis. MATERIALS AND METHODS: Indications for PB biopsy with comprehensive chromosome screening (CCS) included advanced reproductive age, multiple IVF failed cycles or unexplained recurrent miscarriage. The only selection criteria was <8 zygotes. Group A: women<40yrs (n=36 cycles; 206 oocytes); Group B: women≥40yrs (n=90 cycles; 393 oocytes). CCS was performed by comparative genomic hybridization (CGH) (Reprogenetics) or single nucleotide polymorphism (SNP) based microarray (RMA-NJ). RESULTS: Euploid chromosomes were diagnosed in both PBs for 25% of oocytes in Group A and 17.4% of oocytes in Group B (P<0.05). The incidence of 1st PB error alone was similar between the groups (A=22.4% v. B=20%). In contrast, 2nd PB error alone was significantly higher in Group B oocytes (A=22.4% v. B=31.3%; P<0.05) Further analysis of 2nd PB errors revealed a lower contribution involving a single chromosome (A=55.5% v. B=38.7%; P<0.05) and a higher contribution involving ≥3 chromosomes (A=13.6% v. B=36.6%; P<0.05). Aneuploidy was observed for all chromosomes in both groups, with almost 40% of errors contributed by chromosomes 15, 16, 21 & 22. No significant difference was observed between losses and gains for either PB in Group A. In contrast, Group B showed a significant increase in 2nd PB losses (44.4% v 35% 1st PB; P<0.05) corresponding to diploid chromosome in resulting oocytes. The specific CCS technique employed had no bearing on results when analyzed separately. CONCLUSIONS: Advanced reproductive age was directly associated with the incidence and contribution of aneuploidy during 2nd PB division. With an increasing maternal age at first birth further understanding of this relationship is fundamental.

Polar Body Biopsy in the Diagnosis of Monogenic Diseases

For prospective parents at risk of transmitting a monogenic disease, polar body analysis is an option for pre-conception genetic diagnosis. In Germany, polar body analysis is currently performed in only two centers (Lübeck and Regensburg). The authors present a clinical series of 9 couples at risk for the transmission of a monogenic disease who underwent in vitro fertilization with polar body analysis. Nine couples have undergone in vitro fertilization with polar body analysis at the center in Lübeck since 2004. Three healthy children were born after polar body analysis for mucopolysaccharidosis type I, incontinentia pigmenti, and cystic fibrosis. The decision to undergo in vitro fertilization with polar body analysis is not easy for prospective parents to take, even though it often follows years of emotional suffering. Treatment with the methods of reproductive medicine in general, and with polar body analysis in particular, can cause considerable physical and emotional stress. For prospective parents in Germany at risk of transmitting a monogenic disease, polar body-based preimplantation diagnosis is an alternative to prenatal diagnosis and possible termination of pregnancy. The live birth rate per treatment cycle in this clinical series was 30%, which can be considered satisfactory. Nonetheless, most of the couples who did not achieve pregnancy after a first treatment cycle dropped out of treatment prematurely and did not go on to a second cycle.

Preimplantation genetic diagnosis (PGD) for nonsyndromic deafness by polar body and blastomere biopsy

Development of an efficient and reliable PGD protocol for nonsyndromic deafness, by polar body (PB) and blastomere PGD. The GJB2/GJB6 mutations along with 12 polymorphic markers were used in PGD analysis of blastomeres or polar bodies in 14 couples for 35 cycles. Marker informativity, diagnosis rates, Allele Drop Out (ADO) rates and PB1 heterozygosity rates were assessed. Six cycles were performed by PB biopsy, 27 by blastomere and two combined cycles, resulting in delivery of three unaffected children and five ongoing pregnancies. Diagnosis rates for PB and blastomeres were similar. Only 17% PB1s were heterozygote. ADO rates of 19% were observed in both groups. We have developed a single cell multiplex PGD protocol for nonsyndromic deafness with a high efficiency of diagnosis. Most PB1 are homozygous, and similar ADO rates were observed; therefore, blastomere biopsy appears to be the method of choice for this autosomal recessive disease.

Geburt nach Eizellvitrifikation und Polkörperdiagnostik für Mukoviszidose

Fragestellung: Die Polkörperdiagnostik für monogene Erkrankungen wurde bisher an reifen Eizellen (Metaphase II) nach der Eizellgewinnung durchgeführt. Durch das neue Kryokonservierungsverfahren der Vitrifikation ist es möglich, Eizellen ohne Verlust der Befruchtungsfähigkeit einzufrieren. Kann an Eizellen nach vorangegangener Vitrifikation die Fertilisation und Polkörperdiagnostik erfolgreich mit nachfolgender Schwangerschaft und Geburt durchgeführt werden? Material und Methodik: Eine 33-jährige Anlageträgerin für zystische Fibrose (CF), die bereits ein Kind mit Mukoviszidose geboren hat, wurde zur CFTR-Polkörperdiagnostik stimuliert. Aufgrund unerwarteter technischer Probleme mit dem Testsystem für die Polkörperdiagnostik vor der Follikelpunktion wurden in Absprache mit der Patientin die gewonnenen 11 Metaphase-II-(MII)-Eizellen nach der Punktion vitrifiziert. Die Polkörperdiagnostik wurde 3 Monate später an den aufgetauten Eizellen im Rahmen eines künstlichen Zyklus durchgeführt. Ergebnisse: Acht MII-Eizellen waren nach dem Auftauen vital. Fünf dieser Eizellen ließen sich nach ICSI imprägnieren (sog. Vorkern- oder Pronukleusstadium). Zwei Vorkernstadien wurden wegen Mutationsnachweis und eine Eizelle wegen Verlusts des 2. Polkörperchens verworfen, sodass 2 Eizellen mit mütterlichem Wildtyp-Allel weiterkultiviert und transferiert wurden. Es konnte eine fortlaufende Einlingsschwangerschaft erzielt werden. Aufgrund einer schweren Gestose wurde die Patientin bereits in der 26. SSW von einem gesunden, aber unreifen männlichen Neugeborenen per Sectio entbunden. Schlussfolgerung: Nach unserer Kenntnis ist dies der erste Bericht einer erfolgreichen Polkörperdiagnostik für monogene Erkrankungen nach Vitrifikation von MII-Eizellen mit nachfolgender erfolgreicher Schwangerschaft.

Outcome of twin babies free of Von Hippel–Lindau disease after a double-factor preimplantation genetic diagnosis: monogenetic mutation analysis and comprehensive aneuploidy screening

To increase the embryo implantation rate, a double-factor preimplantation genetic diagnosis (DF-PGD) was performed, selecting for transfer potentially euploid evolved embryos free of the mutation responsible for Von Hippel-Lindau syndrome (VHL). Case report. Medical university center and a private IVF center. A patient carrier of the R161Q mutation on the VHL gene. After first polar body (1PB) biopsy, it was analyzed using comparative genomic hybridization (1PB-CGH). On day +3, mutation detection using minisequencing and short tandem repeat analysis was performed in multiple displacement amplification products of a single blastomere per embryo. Transfering embryos free of the disease and originating from euploid oocytes. Nine of the twelve oocytes obtained were successfully analyzed using 1PB-CGH. One of them was aneuploid (1PB #1: 29XX,+2,+10,+12,+17,+19), and the rest were euploid. All of the oocytes were fertilized and became evolved embryos. Six of the embryos were VHL unaffected and had good quality. Five (83%) of them were potentially euploid. According to cytogenetic results, two of the evolved and healthy embryos were transfered, achieving the birth of healthy twin babies. The DF-PGD can be a useful tool to increase implantation of transfered embryos in PGD for monogenic diseases.

Polar body biopsy: a viable alternative to preimplantation genetic diagnosis and screening

Polar body diagnosis (PBD) is a diagnostic method for the indirect genetic analysis of oocytes. Polar bodies are by-products of the meiotic cell cycle, which have no influence on further embryo development. The biopsy of polar bodies can be accomplished either by zona drilling or laser drilling within a very short time period. However, the paternal contribution to the genetic constitution of the developing embryo cannot be diagnosed by PBD. The major application of PBD is the detection of maternally derived chromosomal aneuploidies and translocations in oocytes. For these indications, PBD may offer a viable alternative to blastomere biopsy as the embryo's integrity remains unaffected, in contrast to preimplantation genetic diagnosis (PGD) by blastomere biopsy. The rapid pace of developments in the field of molecular diagnostics will also influence the advantages of PBD, and probably allow more general diagnostic applications in the future.

Polar body biopsy for Curschmann–Steinert disease and successful pregnancy following embryo vitrification

This report describes the first successful case of preimplantation genetic diagnosis (PGD) for myotonic dystrophy type Curschmann-Steinert (DM1) using polar body biopsy with vitrification. A 39-year-old woman with expansion of a CTG trinucleotide repeat in the DMPK gene was included into the study centre's PGD programme. After intracytoplasmic sperm injection, a total of 13 fertilized oocytes were successfully biopsied for the first and second polar body. Nested multiplex polymerase chain reaction was used to amplify the CTG repeat region in DMPK along with two linked polymorphic markers. Six pronuclear stage (PN) oocytes were diagnosed as unaffected and four as affected by the CTG expansion, while analysis of the remaining PN oocytes was inconclusive. Three normal PN oocytes were left in culture to develop to cleavage-stage embryos and the remaining three were vitrified by applying the Cryotop method. On the following day, only one embryo was transferred into the patient's uterus and the remaining two were vitrified because of the progressive threat of ovarian hyperstimulation syndrome. Since the fresh cycle did not result in a pregnancy, 6 months later the two vitrified cleavage-stage embryos were warmed and transferred back to the patient. A clinical pregnancy was established and a healthy boy was born following Caesarean section in week 39 of gestation.

High survival rate of metaphase II human oocytes after first polar body biopsy and vitrification: determining the effect of previtrification conditions

To use metaphase II (MII) bovine oocytes as a model for MII human oocyte cryopreservation and to determine the effect of different previtrification equilibration temperatures, vitrification solutions, zona slitting, and first polar body biopsy on in vitro and in vivo developmental competence of MII human oocytes after the CryoLoop vitrification method. In vitro and in vivo studies. A private infertility clinic. Women undergoing infertility treatment. Metaphase II stage bovine and MII human oocytes underwent first polar body biopsy before cryopreservation in different vitrification conditions, and human oocytes were fertilized by intracytoplasmic sperm injection after warming. The resulting embryos were transferred into women undergoing infertility treatment. Postvitrification morphologic survival, in vitro blastocyst development, and clinical outcome after ET. The equilibration temperature had a significant effect on cryosurvival of both bovine and human oocytes. High (97%-99%) postvitrification survival was achieved for both MII bovine and human oocytes, and high fertilization (90%-97%) at 35 degrees C to 37 degrees C, blastocyst development (18%-45%), and pregnancy (50%) rates were achieved at 35 degrees C with 5.0 mol/L ethylene glycol + 1.3 mol/L dimethyl sulfoxide for MII human oocytes that underwent first polar body biopsy. Previtrification equilibration temperature had a profound effect on the postthaw developmental competence of MII human oocytes in vitro and in vivo. The CryoLoop vitrification of first polar body-biopsied MII human oocytes in the presence of 5 mol/L ethylene glycol plus 1.3 mol/L dimethyl sulfoxide gave the best results in terms of fertilization, embryo development, and implantation rates.

Preimplantation genetic diagnosis (PGD) for maternal dominant disorders: is polar body (PB) better than blastomere biopsy?

OBJECTIVE: Preimplantation diagnosis (PGD) for maternally inherited dominant or X-linked disorders may be performed by direct genetic analysis of the blastomere(s) or by sequential analysis of the first and second polar bodies. If blastomere biopsy is performed, it is recommended to analyze 2 blastomeres for preventing misdiagnosis due to allele drop-out (ADO). With PB analysis, the genotype of the embryo is predicted by deduction. The objective of this study was to compare polar body biopsy with blastomere biopsy, in PGD for maternally inherited disorders, regarding accuracy of the analysis as well as the effect of the biopsy method on embryo development.DESIGN: A prospective study, comparing 31 PGD cycles for maternal dominant disorders analyzed by PB biopsy, to 51 PGD cycles for dominant disorders, analyzed by 2 blastomeres biopsy.MATERIALS AND METHODS: A total of 241 embryos, analyzed by PB biopsy, were evaluated according to the following parameters: biopsy failure rate, amplification failure rate, rate of non-informative first PB, ADO and contamination rates, and the proportion of embryos in which a blastomere biopsy was performed also. Cleavage rate, degree of fragmentation and development parameters of the biopsed embryos on day 3 were assessed too.RESULTS: Failure of biopsy of 1st and 2nd PBs was encountered in 7.5% and 15.7%, respectively. Blastomere Biopsy after attempted PB biopsy was performed in 117 (48.5%) of the embryos due to homozygosity of the 1st PB and a lack of informative markers that could excluded ADO (n=110) and contamination (n=7). Cleavage rate, degree of fragmentation and development parameters of embryos on day 3 were similar in both groups. Ongoing pregnancy rates per embryo transfer were 22.5% for PB biopsy and 17.6% for 2-blastomere biopsy.CONCLUSIONS: We conclude that PB biopsy is more difficult to perform and genetic analysis of PB is hampered by inability to detect maternal contamination in the 1st PB, and inability to distinguish between homozygousity of 1st PB and ADO. On the other hand, PB biopsy may be associated with less disruption of embryonic development. Therefore, we are recommending on PB biopsy only in analyses of maternal disorders that are based on more than 3 informative maternal polymorphic markers. This reduces the need for an additional blastomere biopsy when 1st PB is homozygote. OBJECTIVE: Preimplantation diagnosis (PGD) for maternally inherited dominant or X-linked disorders may be performed by direct genetic analysis of the blastomere(s) or by sequential analysis of the first and second polar bodies. If blastomere biopsy is performed, it is recommended to analyze 2 blastomeres for preventing misdiagnosis due to allele drop-out (ADO). With PB analysis, the genotype of the embryo is predicted by deduction. The objective of this study was to compare polar body biopsy with blastomere biopsy, in PGD for maternally inherited disorders, regarding accuracy of the analysis as well as the effect of the biopsy method on embryo development. DESIGN: A prospective study, comparing 31 PGD cycles for maternal dominant disorders analyzed by PB biopsy, to 51 PGD cycles for dominant disorders, analyzed by 2 blastomeres biopsy. MATERIALS AND METHODS: A total of 241 embryos, analyzed by PB biopsy, were evaluated according to the following parameters: biopsy failure rate, amplification failure rate, rate of non-informative first PB, ADO and contamination rates, and the proportion of embryos in which a blastomere biopsy was performed also. Cleavage rate, degree of fragmentation and development parameters of the biopsed embryos on day 3 were assessed too. RESULTS: Failure of biopsy of 1st and 2nd PBs was encountered in 7.5% and 15.7%, respectively. Blastomere Biopsy after attempted PB biopsy was performed in 117 (48.5%) of the embryos due to homozygosity of the 1st PB and a lack of informative markers that could excluded ADO (n=110) and contamination (n=7). Cleavage rate, degree of fragmentation and development parameters of embryos on day 3 were similar in both groups. Ongoing pregnancy rates per embryo transfer were 22.5% for PB biopsy and 17.6% for 2-blastomere biopsy. CONCLUSIONS: We conclude that PB biopsy is more difficult to perform and genetic analysis of PB is hampered by inability to detect maternal contamination in the 1st PB, and inability to distinguish between homozygousity of 1st PB and ADO. On the other hand, PB biopsy may be associated with less disruption of embryonic development. Therefore, we are recommending on PB biopsy only in analyses of maternal disorders that are based on more than 3 informative maternal polymorphic markers. This reduces the need for an additional blastomere biopsy when 1st PB is homozygote.

Elevated aneuploidy rates in embryos derived from immature oocytes from controlled ovarian hyperstimulation (COH) IVF cycles

OBJECTIVE: To evaluate the fertilization, embryo development and ploidy of embryos derived from metaphase I oocytes obtained from IVF cycles. DESIGN: Case Cohort Review. MATERIALS AND METHODS: Oocytes were retrieved 34-36 hours post hCG injection, oocytes were denuded with hyaluronidase immediately after oocyte retrieval. Intracytoplasmic Sperm Injection (ICSI) was performed 39-40 hours post hCG injection. Resulting embryos were cultured using Vitrolife G-series Plus medium. Embryo quality was assessed on the morning of Day 3 (D3) then again on the morning of D5. Embryo biopsy was performed using a Zilos laser for zona opening to facilitate removal of blastomeres in Ca/Mg free media, and fixation of blastomeres performed using a combination of hypotonic citrate solution followed by Carnoy's fixative. FISH analysis was performed for chromosomal aneuploidy of chromosomes 8,13,14,15,16,17,18,20,21,22,X and Y. RESULTS: 302 embryos were derived from eggs assessed to be at the stage of metaphase I following denudation, but subsequently converted to the metaphase II stage prior to the ICSI procedure. 119 (39%) of these oocytes with delayed maturity fertilized with 2pn, 5(2%) fertilized with 1 pronucleus, 156(52%) did not produce pronuclei, and 18(6%) were not viable at fertilization assessment. 36(30%) of the zygotes displaying normal fertilization reached 6 or more cells on day 3 and 7(19%) of these created good quality blastocysts. 26(34%) of the embryos were screened for aneuploidy and 4(15%) were shown to be euploid for the chromosomes tested. CONCLUSIONS: Our data supports that of DeVos (et al, 1999) and Shu (et al, 2007), where immature oocytes derived from COH are capable of fertilization and good embryo development, but this occurs at a lower rate than expected for mature oocytes. Low fertilization rates, and high aneuploidy rates may be indicative of incompetence either inherent, or caused by maturation of these oocytes from metaphase I to metaphase II in vitro. Polar body biopsy may shed further light on these preliminary observations. Assessing the true clinical importance of immature oocytes is clear, particularly in cycles where few or no mature oocytes are obtained. The clinical competency of immature oocytes derived from COH is critical for appropriate counseling of patients who may be considering the transfer of embryos derived from such oocytes.

Aneuploidy testing by first polar body biopsy of human oocytes matured in vitro from polycystic ovary syndrome patients

OBJECTIVE: The development of immature oocyte retrieval combined with in vitro maturation (IVM) result in oocytes with lower developmental competence than oocytes matured in vivo. The circumstances in vitro or/and polycystic ovaries pathology could influence meiosis which might generate unbalanced chromosomal embryos at fertilization, resulting in the low implantation rate. The goal of this study was to evaluate aneuploidy rate in the first polar body (PB1) of human oocytes matured in vitro from PCOS patients.

Polar Body Diagnosis – A Step in The Right Direction?

Polar body diagnosis (PBD) is a new diagnostic method for the indirect genetic analysis of oocytes, which is carried out as part of in vitro fertilization. The biopsy of polar bodies is technically demanding and cannot be adopted uncritically in routine practice, in the absence of robust data to support this laboratory procedure. Selective literature review and analysis of own PBD data. The main application of PBD is the detection of chromosomal aneuploidies and maternally inherited translocations in oocytes. The major disadvantage of PBD is that the paternal contribution to the genetic constitution of the developing embryo cannot be evaluated. Moreover, the potential value of polar body biopsy for the diagnosis of monogenetic diseases is limited. The role of PBD in improving of success rates in assisted reproduction requires evaluation in further clinical trials. For maternal translocations, PBD can be used to reduce the risk of miscarriage. Rapid development in the field of molecular diagnostic and biopsy techniques will also influence PBD and will most likely allow wider application of this method in the near future.

High survival and developmental rates of vitrified mouse zygotes following polar body biopsy

The effect of two different methods of polar body biopsy followed by vitrification on the survival and development to blastocyst stage of mouse zygotes was examined. Prior to vitrification, a total of 119 and 124 mouse zygotes were subjected to polar body biopsy using either laser-assisted or partial zona dissection (PZD) techniques, respectively. Vitrification was also applied to 122 zona-intact zygotes that served as a control group. Following vitrification, no differences in the rate of zygote survival (95.8%, 91.9% and 94.3%) or in the rate of development to expanded blastocyst stage (82.3%, 79.8% and 82.0%) were observed between the two groups of biopsied zygotes, or between the biopsied zygotes and control zygotes. The mean total number of cells comprising the blastocysts of controls (77.1 ± 4.7) was comparable to the mean cell number recorded in the laser (66.4 ± 4.7) and PZD (69.7 ± 5.3) groups. Blastocysts developed from laser-treated zygotes hatched much earlier than blastocysts developed from the control and PZD groups of zygotes ( P < 0.001). The data obtained in the present study demonstrate that, irrespective of the biopsy method used prior to vitrification, mouse zygotes survive and develop to blastocysts upon warming in proportions similar to those of non-biopsied zygotes.