Talk:Preimplantation Genetic Diagnosis
Noninvasive preimplantation genetic testing for aneuploidy in spent medium may be more reliable than trophectoderm biopsy
Proc Natl Acad Sci U S A. 2019 Jul 9;116(28):14105-14112. doi: 10.1073/pnas.1907472116. Epub 2019 Jun 24.
Huang L1,2, Bogale B2, Tang Y3,4, Lu S5, Xie XS6,3,4, Racowsky C7.
Preimplantation genetic testing for aneuploidy (PGT-A) with trophectoderm (TE) biopsy is widely applied in in vitro fertilization (IVF) to identify aneuploid embryos. However, potential safety concerns regarding biopsy and restrictions to only those embryos suitable for biopsy pose limitations. In addition, embryo mosaicism gives rise to false positives and false negatives in PGT-A because the inner cell mass (ICM) cells, which give rise to the fetus, are not tested. Here, we report a critical examination of the efficacy of noninvasive preimplantation genetic testing for aneuploidy (niPGT-A) in the spent culture media of human blastocysts by analyzing the cell-free DNA, which reflects ploidy of both the TE and ICM. Fifty-two frozen donated blastocysts with TE biopsy results were thawed; each of their spent culture medium was collected after 24-h culture and analyzed by next-generation sequencing (NGS). niPGT-A and TE-biopsy PGT-A results were compared with the sequencing results of the corresponding embryos, which were taken as true results for aneuploidy reporting. With removal of all corona-cumulus cells, the false-negative rate (FNR) for niPGT-A was found to be zero. By applying an appropriate threshold for mosaicism, both the positive predictive value (PPV) and specificity for niPGT-A were much higher than TE-biopsy PGT-A. Furthermore, the concordance rates for both embryo ploidy and chromosome copy numbers were higher for niPGT-A than TE-biopsy PGT-A. These results suggest that niPGT-A is less prone to errors associated with embryo mosaicism and is more reliable than TE-biopsy PGT-A. KEYWORDS: ICSI; culture medium; human blastocyst; noninvasive PGT-A; preimplantation genetic testing PMID: 31235575 PMCID: PMC6628824 [Available on 2019-12-24] DOI: 10.1073/pnas.1907472116
Euploidy in relation to blastocyst sex and morphology
J Assist Reprod Genet. 2018 Jul 20. doi: 10.1007/s10815-018-1262-x. [Epub ahead of print]
Wang A1, Kort J1, Behr B1, Westphal LM2,3.
PURPOSE: The objective of our study is to assess the relationship of embryo ploidy status in relation to embryo sex, morphological characteristics, and transfer parameters. METHODS: This is a retrospective cohort study at an academic medical center of patients who underwent in vitro fertilization with preimplantation genetic screening (PGS) from 2010 to 2015. Embryos were screened with 24-chromosome preimplantation genetic screening with day 5/6 trophectoderm biopsy. We investigated embryo euploidy in relation to morphology (expansion, inner cell mass, trophectoderm), embryo sex, biopsy day, and blastocyst cohort size. We used multivariate logistic regression to calculate odds ratios of euploidy in relation to these parameters. RESULTS: A total of 1559 embryos from 316 cycles and 233 patients (mean maternal age = 37.8 ± 4.2 years) were included in the analysis. Six hundred and twenty-eight blastocysts (40.3%) were found to be euploid. Expansion (p < 0.001), inner cell mass (ICM) (p < 0.01), and trophectoderm grade (p < 0.001) were significantly associated with embryo ploidy in bivariate models controlling for maternal age, while embryo sex, biopsy day, and blastocyst cohort size were not associated with embryo ploidy. In a multivariate model, we found that maternal age (p < 0.001), higher grade of expansion (p < 0.01), and better quality trophectoderm (p < 0.001 for A compared to C grade) remained significantly associated with increased embryo euploidy, but ICM grade was no longer significant. Embryo sex was not associated with ploidy status, though male embryos were found to be associated with higher trophectoderm scores (p < 0.02). CONCLUSIONS: This is the largest study to date to investigate PGS-tested embryo sex and ploidy status. While maternal age and some morphological parameters (expansion, trophectoderm grade) are associated with euploidy in our cohort, other parameters such as embryo sex, biopsy day, and cohort size are not. Though embryo sex was not associated with euploidy, male embryos were found to be associated with higher trophectoderm grades. Additional investigation in larger studies is warranted. KEYWORDS: Embryo sex; Euploidy; Inner cell mass; Morphology; Preimplantation genetic screening; Trophectoderm PMID: 30030712 DOI: 10.1007/s10815-018-1262-x
Review of patient decision-making factors and attitudes regarding preimplantation genetic diagnosis
Clin Genet. 2018 Jul;94(1):22-42. doi: 10.1111/cge.13174. Epub 2018 Feb 11.
Genoff Garzon MC1, Rubin LR1, Lobel M2, Stelling J3,4, Pastore LM4.
The increasing technical complexity and evolving options for repro-genetic testing have direct implications for information processing and decision making, yet the research among patients considering preimplantation genetic diagnosis (PGD) is narrowly focused. This review synthesizes the literature regarding patient PGD decision-making factors, and illuminates gaps for future research and clinical translation. Twenty-five articles met the inclusion criteria for evaluating experiences and attitudes of patients directly involved in PGD as an intervention or considering using PGD. Thirteen reports were focused exclusively on a specific disease or condition. Five themes emerged: (1) patients motivated by prospects of a healthy, genetic-variant-free child, (2) PGD requires a commitment of time, money, energy and emotions, (3) patients concerned about logistics and ethics of discarding embryos, (4) some patients feel sense of responsibility to use available technologies, and (5) PGD decisions are complex for individuals and couples. Patient research on PGD decision-making processes has very infrequently used validated instruments, and the data collected through both quantitative and qualitative designs have been inconsistent. Future research for improving clinical counseling is needed to fill many gaps remaining in the literature regarding this decision-making process, and suggestions are offered. KEYWORDS: PGD; decision making; ethics; genetic counseling; health attitudes; knowledge; practice; preimplantation genetic diagnosis; psychology; reproductive endocrinology and infertility PMID: 29120067 DOI: 10.1111/cge.13174
Preimplantation genetic diagnosis as a strategy to prevent having a child born with an heritable eye disease
Ophthalmic Genet. 2018 Aug;39(4):450-456. doi: 10.1080/13816810.2018.1474368. Epub 2018 May 21.
Yahalom C1, Macarov M1, Lazer-Derbeko G2, Altarescu G2, Imbar T3, Hyman JH3, Eldar-Geva T4, Blumenfeld A1.
Abstract BACKGROUND: In developed countries, genetically inherited eye diseases are responsible for a high percentage of childhood visual impairment. We aim to report our experience using preimplantation genetic diagnostics (PGD) in order to avoid transmitting a genetic form of eye disease associated with childhood visual impairment and ocular cancer. MATERIAL AND METHODS: Retrospective case series of women who underwent in vitro fertilization (IVF) and PGD due to a familial history of inherited eye disease and/or ocular cancer, in order to avoid having a child affected with the known familial disease. Each family underwent genetic testing in order to identify the underlying disease-causing mutation. IVF and PGD treatment were performed; unaffected embryos were implanted in their respective mothers. RESULTS: Thirty-five unrelated mothers underwent PGD, and the following hereditary conditions were identified in their families: albinism (10 families); retinitis pigmentosa (7 families); retinoblastoma (4 families); blue cone monochromatism, achromatopsia, and aniridia (2 families each); and Hermansky-Pudlak syndrome, Leber congenital amaurosis, Norrie disease, papillorenal syndrome, primary congenital cataract, congenital glaucoma, Usher syndrome type 1F, and microphthalmia with coloboma (1 family each). Following a total of 88 PGD cycles, 18 healthy (i.e., unaffected) children were born. CONCLUSIONS: Our findings underscore the importance an ophthalmologist plays in informing patients regarding the options now available for using prenatal and preimplantation genetic diagnosis to avoid having a child with a potentially devastating genetic form of eye disease or ocular cancer. This strategy is highly relevant, particularly given the limited options currently available for treating these conditions. KEYWORDS: Childhood visual impairment; PGD; genetic counselling; inherited eye diseases; prevention PMID: 29781739 DOI: 10.1080/13816810.2018.1474368
The first successful application of preimplantation genetic diagnosis for hearing loss in Iran
Cell Mol Biol (Noisy-le-grand). 2018 Jun 30;64(9):1718.
Karimi Yazdi A1, Davoudi-Dehaghani E2, Rabbani Anari M1, Fouladi P2, Ebrahimi E3, Sabeghi S2, Eftekharian A4, Fatemi KS2, Emami H1, Sharifi Z2, Ramezanzadeh F5, Tajdini A6, Zeinali S2, Amanpour S5.
Hearing impairment (HI) caused by mutations in the connexin-26 gene (GJB2) accounts for the majority of cases with inherited, nonsyndromic sensorineural hearing loss. Due to the illegality of the abortion of deaf fetuses in Islamic countries, preimplantation genetic diagnosis (PGD) is a possible solution for afflicted families to have a healthy offspring. This study describes the first use of PGD for GJB2 associated non-syndromic deafness in Iran. GJB2 donor splicing site IVS1+1G>A mutation analysis was performed using Sanger sequencing for a total of 71 Iranian families with at least 1 deaf child diagnosed with non-syndromic deafness. In Vitro Fertilization (IVF) was performed, followed by PGD for a cousin couple with a 50% chance of having an affected child. Bi-allelic pathogenic mutations were found in a total of 12 families (~17 %); of which a couple was a PGD volunteer. The deaf woman in this family was homozygous and her husband was a carrier of the IVS1+1G>A gene mutation. Among 8 biopsied embryos, two healthy embryos were implanted which resulted in a single pregnancy and subsequent birth of a healthy baby boy. This is the first report of a successful application of PGD for hearing loss in Iran. Having a baby with a severe hearing impairment often imposes families with long-term disease burden and heavy therapy costs. Today PGD has provided an opportunity for high-risk individuals to avoid the birth of a deaf child. KEYWORDS: Assisted reproductive technology; Connexin-26; Preimplantation genetic diagnosis.; Sensorineural deafness PMID: 30030956
Genetic Analysis of Human Preimplantation Embryos
Curr Top Dev Biol. 2016;120:421-47. doi: 10.1016/bs.ctdb.2016.04.009. Epub 2016 May 31.
Garcia-Herrero S1, Cervero A1, Mateu E1, Mir P1, Póo ME1, Rodrigo L1, Vera M1, Rubio C2.
Preimplantation development comprises the initial stages of mammalian development, before the embryo implants into the mother's uterus. In normal conditions, after fertilization the embryo grows until reaching blastocyst stage. The blastocyst grows as the cells divide and the cavity expands, until it arrives at the uterus, where it "hatches" from the zona pellucida to implant into the uterine wall. Nevertheless, embryo quality and viability can be affected by chromosomal abnormalities, most of which occur during gametogenesis and early embryo development; human embryos produced in vitro are especially vulnerable. Therefore, the selection of chromosomally normal embryos for transfer in assisted reproduction can improve outcomes in poor-prognosis patients. Additionally, in couples with an inherited disorder, early diagnosis could prevent pregnancy with an affected child and would, thereby, avoid the therapeutic interruption of pregnancy. These concerns have prompted advancements in the use of preimplantation genetic diagnosis (PGD). Genetic testing is applied in two different scenarios: in couples with an inherited genetic disorder or carriers of a structural chromosomal abnormality, it is termed PGD; in infertile couples with increased risk of generating embryos with de novo chromosome abnormalities, it is termed preimplantation genetic screening, or PGS. © 2016 Elsevier Inc. All rights reserved. KEYWORDS: Aneuploidy; Array-CGH; Embryo biopsy; Monogenic disease; Mosaicism; NGS; PGS; Translocation PMID 27475859
Preimplantation genetic screening for all 24 chromosomes by microarray comparative genomic hybridization significantly increases implantation rates and clinical pregnancy rates in patients undergoing in vitro fertilization with poor prognosis
J Hum Reprod Sci. 2016 Apr-Jun;9(2):94-100. doi: 10.4103/0974-1208.183512.
Majumdar G1, Majumdar A1, Lall M2, Verma IC3, Upadhyaya KC4.
CONTEXT: A majority of human embryos produced in vitro are aneuploid, especially in couples undergoing in vitro fertilization (IVF) with poor prognosis. Preimplantation genetic screening (PGS) for all 24 chromosomes has the potential to select the most euploid embryos for transfer in such cases. AIM: To study the efficacy of PGS for all 24 chromosomes by microarray comparative genomic hybridization (array CGH) in Indian couples undergoing IVF cycles with poor prognosis. SETTINGS AND DESIGN: A retrospective, case-control study was undertaken in an institution-based tertiary care IVF center to compare the clinical outcomes of twenty patients, who underwent 21 PGS cycles with poor prognosis, with 128 non-PGS patients in the control group, with the same inclusion criterion as for the PGS group. MATERIALS AND METHODS: Single cells were obtained by laser-assisted embryo biopsy from day 3 embryos and subsequently analyzed by array CGH for all 24 chromosomes. Once the array CGH results were available on the morning of day 5, only chromosomally normal embryos that had progressed to blastocyst stage were transferred. RESULTS: The implantation rate and clinical pregnancy rate (PR) per transfer were found to be significantly higher in the PGS group than in the control group (63.2% vs. 26.2%, P = 0.001 and 73.3% vs. 36.7%, P = 0.006, respectively), while the multiple PRs sharply declined from 31.9% to 9.1% in the PGS group. CONCLUSIONS: In this pilot study, we have shown that PGS by array CGH can improve the clinical outcome in patients undergoing IVF with poor prognosis. KEYWORDS: Array comparative genomic hybridization; clinical outcomes; embryo selection; in vitro fertilization; preimplantation genetic screening PMID 27382234
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The Influence of Single Nucleotide Polymorphism Microarray-Based Molecular Karyotype on Preimplantation Embryonic Development Potential
PLoS One. 2015 Sep 18;10(9):e0138234. doi: 10.1371/journal.pone.0138234. eCollection 2015.
Li G1, He N1, Jin H1, Liu Y1, Guo Y1, Su Y1, Sun Y1.
In order to investigate the influence of the molecular karyotype based on single nucleotide polymorphism (SNP) microarray on embryonic development potential in preimplantation genetic diagnosis (PGD), we retrospectively analyzed the clinical data generated by PGD using embryos retrieved from parents with chromosome rearrangements in our center. In total, 929 embryos from 119 couples had exact diagnosis and development status. The blastocyst formation rate of balanced molecular karyotype embryos was 56.6% (276/488), which was significantly higher than that of genetic imbalanced embryos 24.5% (108/441) (P<0.001). No significant difference was detected in blastocyst formation rates in the groups of maternal age<30, 30-35 and >35 respectively. Blastocyst formation rates of male and female embryos were 44.5% (183/411) and 38.8% (201/518) respectively, with no significant difference between them (P>0.05). The rates of balanced molecular karyotype embryos vary from groups of embryos with different cell numbers at 68 hours after insemination. The blastocyst formation rate of embryos with 6-8 cells (48.1%) was significantly higher than that of embryos with <6 cells (23.9%) and with >8 cells (42.9%) (P<0.05). As for the unbalanced embryos, there was no significant difference of the distribution of abnormal molecular karyotypes in the subgroup of the arrest, morula and blastocyst. Thus, we conclude that embryos with balanced molecular karyotype have significant higher development potential than those with imbalanced molecular karyotype whilst maternal age, embryo gender and types of abnormal molecular karyotype have no significant influence on blastocyst formation. Compared with embryos with <6 and >8 cells, embryos with 6-8 blastomeres have higher rate of balanced molecular karyotype and blastocyst formation.
Preimplantation genetic screening (PGS) still in search of a clinical application: a systematic review
Reprod Biol Endocrinol. 2014 Mar 15;12:22. doi: 10.1186/1477-7827-12-22.
Gleicher N1, Kushnir VA, Barad DH.
Only a few years ago the American Society of Assisted Reproductive Medicine (ASRM), the European Society for Human Reproduction and Embryology (ESHRE) and the British Fertility Society declared preimplantation genetic screening (PGS#1) ineffective in improving in vitro fertilization (IVF) pregnancy rates and in reducing miscarriage rates. A presumably upgraded form of the procedure (PGS#2) has recently been reintroduced, and is here assessed in a systematic review. PGS#2 in comparison to PGS#1 is characterized by: (i) trophectoderm biopsy on day 5/6 embryos in place of day-3 embryo biopsy; and (ii) fluorescence in-situ hybridization (FISH) of limited chromosome numbers is replaced by techniques, allowing aneuploidy assessments of all 24 chromosome pairs. Reviewing the literature, we were unable to identify properly conducted prospective clinical trials in which IVF outcomes were assessed based on "intent to treat". Whether PGS#2 improves IVF outcomes can, therefore, not be determined. Reassessments of data, alleged to support the efficacy of PGS#2, indeed, suggest the opposite. Like with PGS#1, the introduction of PGS#2 into unrestricted IVF practice again appears premature, and threatens to repeat the PGS#1 experience, when thousands of women experienced reductions in IVF pregnancy chances, while expecting improvements. PGS#2 is an unproven and still experimental procedure, which, until evidence suggests otherwise, should only be offered under study conditions, and with appropriate informed consents.
Origins and rates of aneuploidy in human blastomeres
Fertil Steril. 2011 Dec 21. [Epub ahead of print]
Rabinowitz M, Ryan A, Gemelos G, Hill M, Baner J, Cinnioglu C, Banjevic M, Potter D, Petrov DA, Demko Z. Source Natera Inc., Redwood City, California; School of Engineering, Aeronautics and Astronautics. Abstract OBJECTIVE: To characterize chromosomal error types and parental origin of aneuploidy in cleavage-stage embryos using an informatics-based technique that enables the elucidation of aneuploidy-causing mechanisms. DESIGN: Analysis of blastomeres biopsied from cleavage-stage embryos for preimplantation genetic screening during IVF. SETTING: Laboratory. PATIENT(S): Couples undergoing IVF treatment. INTERVENTION(S): Two hundred seventy-four blastomeres were subjected to array-based genotyping and informatics-based techniques to characterize chromosomal error types and parental origin of aneuploidy across all 24 chromosomes. MAIN OUTCOME MEASURE(S): Chromosomal error types (monosomy vs. trisomy; mitotic vs. meiotic) and parental origin (maternal vs. paternal). RESULT(S): The rate of maternal meiotic trisomy rose significantly with age, whereas other types of trisomy showed no correlation with age. Trisomies were mostly maternal in origin, whereas paternal and maternal monosomies were roughly equal in frequency. No examples of paternal meiotic trisomy were observed. Segmental error rates were found to be independent of maternal age.
CONCLUSION(S): All types of aneuploidy that rose with increasing maternal age can be attributed to disjunction errors during meiosis of the oocyte. Chromosome gains were predominantly maternal in origin and occurred during meiosis, whereas chromosome losses were not biased in terms of parental origin of the chromosome. The ability to determine the parental origin for each chromosome, as well as being able to detect whether multiple homologs from a single parent were present, allowed greater insights into the origin of aneuploidy. Copyright © 2012 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.
Preimplantation genetic diagnosis for inherited breast cancer: first clinical application and live birth in Spain
Fam Cancer. 2011 Dec 18. [Epub ahead of print]
Ramón Y Cajal T, Polo A, Martínez O, Giménez C, Arjona C, Llort G, Bassas L, Viscasillas P, Calaf J. Source Medical Oncology Department, Sant Pau Hospital, Barcelona, Spain, email@example.com.
Carriers of a mutation in BRCA1/2 genes confront a high lifetime risk of breast and ovarian cancer and fifty percent probability of passing the mutation to their offspring. Current options for risk management influence childbearing decisions. The indications for preimplantation genetic diagnosis (PGD) have now been expanded to include predisposition for single-gene, late-onset cancer but few cases have been reported to date despite the favorable opinion among professionals and carriers. A 28-year-old BRCA1 mutation carrier (5273G>A in exon 19) with a strong maternal history of breast cancer and 2 years of infertility decided to pursue PGD to have a healthy descendent after an accurate assessment of her reproductive options. The procedure was approved by the national regulation authority and a PGD cycle was initiated. Four out of 6 embryos harbored the mutation. The two unaffected embryos were implanted in the uterus. A singleton pregnancy was achieved and a male baby was delivered at term. Consented umbilical cord blood testing confirmed the accuracy of the technique. Individualized PGD for inherited breast predisposition is feasible in the context of a multidisciplinary team.
The genetic screening of preimplantation embryos by comparative genomic hybridisation
Reprod Biol. 2011 Dec;11 Suppl 3:51-60.
Traversa MV, Marshall J, McArthur S, Leigh D. Source Genea, Level 2, 321 Kent Street, Sydney NSW 2000, Australia; e-mail: firstname.lastname@example.org.
Comparative genomic hybridization (CGH) is an indirect DNA-based test which allows for the accurate analysis of aneuploidy involving any of the 24 types of chromosomes present (22 autosomes and the X and Y sex chromosomes). Traditionally, embryos have been screened using fluorescence in situ hybridization (FISH) - a technique that was limited in the number of chromosomes able to be identified in any one sample. Early CGH reports on aneuploidy in preimplantation embryos showed that any of the 24 chromosomes could be involved and so FISH methods were going to be ineffective in screening out abnormal embryos. Our results from routine clinical application of array CGH in preimplantation genetic diagnosis (PGD) patients confirm previous reports on patterns of chromosomal contribution to aneuploidy. The pregnancy outcomes following embryo transfer also indicate that despite the requirement to freeze embryos, rates are encouraging, and successful ongoing pregnancies can be achieved.
Preimplantation genetic screening: does it help or hinder IVF treatment and what is the role of the embryo?
J Assist Reprod Genet. 2011 Sep;28(9):833-49. Epub 2011 Jul 9.
Ly KD, Agarwal A, Nagy ZP. Source Center for Reproductive Medicine, Cleveland Clinic, Cleveland, Ohio, USA. email@example.com
Despite an ongoing debate over its efficacy, preimplantation genetic screening (PGS) is increasingly being used to detect numerical chromosomal abnormalities in embryos to improve implantation rates after IVF. The main indications for the use of PGS in IVF treatments include advanced maternal age, repeated implantation failure, and recurrent pregnancy loss. The success of PGS is highly dependent on technical competence, embryo culture quality, and the presence of mosaicism in preimplantation embryos. Today, cleavage stage biopsy is the most commonly used method for screening preimplantation embryos for aneuploidy. However, blastocyst biopsy is rapidly becoming the more preferred method due to a decreased likelihood of mosaicism and an increase in the amount of DNA available for testing. Instead of using 9 to 12 chromosome FISH, a 24 chromosome detection by aCGH or SNP microarray will be used. Thus, it is advised that before attempting to perform PGS and expecting any benefit, extended embryo culture towards day 5/6 should be established and proven and the clinical staff should demonstrate competence with routine competency assessments. A properly designed randomized control trial is needed to test the potential benefits of these new developments.
Preimplantation diagnosis of genetic diseases
J Postgrad Med. 2010 Oct-Dec;56(4):317-20.
Adiga SK, Kalthur G, Kumar P, Girisha KM. Source Division of Reproductive Medicine, Kasturba Medical College, Manipal University, Manipal, India.
One of the landmarks in clinical genetics is prenatal diagnosis of genetic disorders. The recent advances in the field have made it possible to diagnose the genetic conditions in the embryos before implantation in a setting of in vitro fertilization. Polymerase chain reaction and fluorescence in situ hybridization are the two common techniques employed on a single or two cells obtained via embryo biopsy. The couple who seek in vitro fertilization may screen their embryos for aneuploidy and the couple at risk for a monogenic disorder but averse to abortion of the affected fetuses after prenatal diagnosis, are likely to be the best candidates to undergo this procedure. This article reviews the technique, indications, benefits, and limitations of pre-implantation genetic testing in clinical practice. PMID 20935409
The effects of different laser pulse lengths on the embryo biopsy procedure and embryo development to the blastocyst stage
J Assist Reprod Genet. 2010 Nov;27(11):663-7. Epub 2010 Aug 5.
Taylor TH, Gilchrist JW, Hallowell SV, Hanshew KK, Orris JJ, Glassner MJ, Wininger JD. Source Main Line Fertility and Reproductive Medicine, 130 S. Bryn Mawr Ave, Ground Floor, D Wing, Bryn Mawr, PA 19010, USA. firstname.lastname@example.org Abstract PURPOSE: a laser is commonly used to remove a blastomere from an embryo for genetic testing. The laser uses intense heat which could possibly disrupt embryo development. It is the goal of this study to test the effects of different laser pulse lengths (and consequently heat) on the embryo biopsy procedure and embryo development. METHODS: each embryo biopsy was performed randomly utilizing laser pulse lengths of 0.604mS (group I), 0.708mS (group II), and 1.010mS (group III). RESULTS: for groups I, II, and III, 83, 86, and 71 embryos were biopsied, respectively. There was no difference in day 5 embryo quality or lysed blastomeres between groups. Average number of blastomeres biopsied between group I (1.0 ± 0.0), II (1.0 ± 0.2), and III (1.1 ± 0.2) was significant (0.0001). CONCLUSION: our data demonstrates that laser pulse length does not influence the embryo biopsy procedure or embryo development.