Outcome of preimplantation genetic diagnosis of translocations

Objective: To review 35 cases of preimplantation genetic diagnosis (PGD) of translocations with several methods, including telomeric probes.

Design: Retrospective study.

Setting: Clinical IVF laboratory.

Patient(s): Thirty-five couples with one partner carrying a chromosomal translocation.

Intervention(s): PGD of translocation after polar-body or embryo biopsy.

Main Outcome Measure(s): Pregnancy outcome.

Result(s): Several trends were observed. First, PGD can achieve a statistically significant reduction in spontaneous abortion, from 95% to 13%. Second, the chances of achieving pregnancy are correlated with 50% or more of the embryos being chromosomally normal. Third, patients with robertsonian translocations produced fewer abnormal gametes and more pregnancies than did patients with reciprocal translocations. Fourth, a new fluorescence in situ hybridization protocol for PGD of translocations, which involves applying telomeric probes, has proved adequately reliable with a 6% average error rate.

Conclusion(s): PGD of translocations achieves a statistically significant reduction in spontaneous abortion, both for polar-body and blastomere biopsy cases. Pregnancy outcome depended on the number of normal embryos available for transfer, with patients having <50% abnormal embryos achieving the most pregnancies. Because robertsonian translocations caused fewer abnormal embryos than reciprocal translocations, they also resulted in higher rates of implantation.     

Efficacy and clinical outcome of preimplantation genetic diagnosis using FISH for couples of reciprocal and Robertsonian translocations: the Korean experience

OBJECTIVE: To evaluate the efficacy and clinical outcome of preimplantation genetic diagnosis (PGD) using fluorescence in situ hybridization (FISH) for couples with chromosomal translocations. METHODS: PGD using FISH was performed in 59 cycles of 43 couples with reciprocal translocations, and 11 cycles of 6 couples with Robertsonian translocations. The diagnostic and clinical data were reviewed in a series of 70 treatment cycles of 49 couples from January 2001 to June 2002 at Samsung Cheil Hospital, Korea. RESULTS: A total of 1408 oocytes were retrieved, and 938 (81.7%) out of 1148 matured oocytes were fertilized by intracytoplasmic sperm injection (ICSI). Single blastomere biopsy and FISH analysis were successfully carried out in 99.3% (890/896) and 94.4% (840/890), respectively. Among 193 normal or balanced embryos, 169 embryos were transferred in 64 cycles (91.4% per started cycle). Twenty clinical pregnancies including two ectopic pregnancies and three spontaneous miscarriages (28.6% per started cycle, 31.3% per transfer cycle, 40.8% per couple) were established. Of the three spontaneous miscarriages, one was karyotyped as normal, one had an unbalanced arrangement and one was tetraploid. One case of preterm twin delivery occurred and 16 healthy babies were delivered in 12 single and 2 twin pregnancies. CONCLUSION: The clinical outcome was successful in 28.6% (14/49) of the treated couples with translocations after PGD. The spontaneous abortion rate was significantly reduced from 95.8% (69/72) to 16.7% (3/18) in these couples.     

拷贝数变异测序在染色体易位夫妇植入前遗传学诊断中的临床应用

目的探讨拷贝数变异测序(copy number variation sequencing, CNV-seq)用于染色体易位夫妇胚胎植入前诊断的应用价值。 方法回顾性分析2017年1月至2018年12月,在广东省妇幼保健院生殖健康与不孕症科进行植入前遗传学诊断(preimplantation genetic diagnosis,PGD)的211对染色体易位夫妇患者的临床病例。使用CNV-seq对胚胎染色体进行检测,并对患者一般信息和PGD结果进行分析。 结果1210个胚胎中,被检出837个(79.2%)胚胎存在染色体异常,373个(30.8%)胚胎为整倍体。在241个PGD周期中,68个(27.6%)周期所有胚胎均存在染色体异常,178个(72.4%)周期至少含有一个整倍体胚胎。在176个移植周期中,130个(73.9%)确定临床妊娠,已出生46个健康婴儿,12例发生早期流产。 结论CNV-seq可准确地区分胚胎染色体是否存在异常,避免因胚胎含有染色体异常而被移植,是一种可靠而准确的PGD技术。     

Preimplantation diagnosis for p53 tumour suppressor gene mutations

Preimplantation genetic diagnosis (PGD) was introduced for high-risk couples to avoid establishing affected pregnancies potentially requiring termination following prenatal diagnosis. This opens the possibility for PGD for late onset disorders with genetic predisposition, including inherited cancer predisposition, because only embryos free from the predisposing gene may be transferred back to the patient, with no potential risk for pregnancy termination. PGD was performed for two couples, one with maternally and one with paternally derived p53 tumour-suppressor mutations, 902insC in exon 8 and G524A in exon 5, respectively. This involved a standard IVF protocol, allowing oocytes or embryos to be tested prior to their transfer back to uterus. Maternal mutation was tested by sequential PCR analysis of the first and second polar bodies, removed following maturation and fertilization of oocytes, while paternal mutation analysis required embryo biopsy at the cleavage stage. To avoid misdiagnosis due to allele drop out, multiplex nested PCR was applied, involving p53 mutation analysis simultaneously with the linked short tandem repeats in intron 1. Of 10 oocytes tested in two PGD cycles for 902insC mutation, four unaffected oocytes were pre-selected for transfer yielding no clinical pregnancy. Of 18 embryos analysed in two cycles for G524A mutation, seven mutation-free embryos were detected, two of which were transferred in each cycle, resulting in a singleton pregnancy and birth of a mutation-free child. This is the first PGD for inherited cancer predisposition determined by p53 tumour suppressor mutations, resulting in a clinical pregnancy and birth of a child free from inherited cancer predisposition.     

Increased frequency of female partner chromosomal abnormalities in patients with high-order implantation failure after in vitro fertilization

OBJECTIVE: To find the type and frequency of chromosomal abnormalities in a selected group of high-order implantation failure (> or =6 IVF trials and > or =15 transferred embryos) and to evaluate its impact on pregnancy outcome.DESIGN: A retrospective study.SETTING: In vitro fertilization (IVF) unit in a university affiliated hospital.PATIENT(S): Sixty-five couples with high-order implantation failure in IVF and embryo transfer.INTERVENTION(S): In vitro fertilization/embryo transfer (ET), work-up for implantation failure, cytogenetic analysis of the couple.MAIN OUTCOME MEASURE(S): We studied the type and frequency of chromosomal changes, quality of embryos, cumulative pregnancy rates, and pregnancy outcome.RESULT(S): The mean number of treatment cycles per patient, before karyotyping was 7.8 +/- 2.4 (range: 6 to 16 cycles). The mean cumulative number of all transferred embryos per patient was 25.7 +/- 10.3 (range: 9 to 65 embryos). Chromosomal abnormalities were found in 10 of 65 (15.4%) cases: translocations in six, mosaicism in two, and inversion or deletion in another two. The morphologic characteristics of the transferred embryos and the cumulative pregnancy rates were similar in patients with implantation failure with and without chromosomal changes. Three of the 16 patients with abnormal karyotype delivered and three miscarried within a follow-up period of 1 year.CONCLUSION(S): A high frequency of chromosomal aberrations was found in a selected group of high-order implantation failures, a similar frequency to recurrent miscarriages. Karyotyping is recommended as part of the work-up for repeated implantation failure in assisted reproduction. Treatment options include further IVF trials, preimplantation genetic diagnosis, or oocyte donation, tailored according to the type of chromosomal change. An international registry should be considered to assist in counseling these patients.     

Blastocyst trophectoderm biopsy and preimplantation genetic diagnosis for familial monogenic disorders and chromosomal translocations

OBJECTIVE: Modern in vitro fertilization practices involve transfer of embryos as blastocysts, when anabolic metabolism is well established and pregnancy rates can be maintained while transferring embryos singly to avoid multiple pregnancies. Embryo biopsy for preimplantation genetic diagnosis (PGD), however, is generally performed on day 3, when the embryo comprises just 6 to 8 cells, one or two of which are removed for testing. Implantation rates and clinical pregnancy rates have remained relatively low and a harmful effect from losing one or more cells from such early embryos has not been excluded. METHODS: We performed a sequential study involving 399 egg retrievals and 1879 embryo biopsies for patients undergoing PGD to avoid a serious monogenic disease or an unbalanced chromosomal translocation. We compared implantation and viable pregnancy rates after biopsies taken on day 3 (cleavage-stage biopsy) with biopsies delayed until day 5 or 6, when the embryo is a blastocyst and 5 or more cells can be sampled from the trophectoderm while the inner cell mass, from which the fetus develops, remains intact. All embryos were transferred as blastocysts. RESULTS: Despite fewer blastocysts than cleavage embryos biopsied and tested (3.6 compared to 6.6), implantation rates per embryo transferred were 43.4% if biopsied at the blastocyst stage and 25.6% if biopsied at the cleavage stage (P < 0.01), with ongoing or live-birth pregnancy rates per egg retrieval of 34.2% (average transfer number 1.1) for blastocyst biopsies and 25.5% (transfer number 1.6) for cleavage stage biopsies (P < 0.05, 1-tailed). The multiple pregnancy rate for monogenic disease exclusion fell from 16.7% to 2% (P = 0.04, 1-tailed). CONCLUSIONS: For exclusion of genetic disease, day 5-6 blastocyst-stage biopsies are more likely to be followed by implantation and singleton births than is the case after PGD performed on day 3.     

Embryo transfer is equally effective at cleavage stage and blastocyst stage: a randomized prospective study

OBJECTIVE: To compare the implantation and pregnancy rates after cleavage stage embryo transfer (ET) with transfer of blastocyst-stage (days 5-6) embryos. STUDY DESIGN: Prospective randomized trial at an assisted reproduction unit in a university hospital. Women with six or more follicles at the last ultrasound scan before oocyte aspiration were randomized for transfer of a maximum of two embryos after 2-3 days (n = 80) or after 5-6 days (n = 64) of culture. Embryo quality, implantation and pregnancy rates were evaluated. Statistical significance was tested with the Chi-square test and Fisher's exact test. RESULT(S): No significant difference was observed in implantation rates (21.1% versus 20.9%, respectively) and clinical pregnancy rates (36.7% versus 32.5% respectively) after blastocyst and cleavage stage transfers for the two groups. The pregnancy rate among subjects who had at least one good quality embryo transferred was 37.5% per day 2-3 ET and 60% per day 5-6 ET. CONCLUSION(S): The overall implantation and pregnancy rates after embryo transfer at cleavage stage and at blastocyst stage transfer were not statistically different. Women who had at least one good quality blastocyst (n = 25) had a high pregnancy rate (60% per ET). Blastocyst transfer is a good alternative for couples with many good quality embryos on day 2 after insemination.     

Over a decade of experience with preimplantation genetic diagnosis: a multicenter report

OBJECTIVE: To review a 12-year experience of the world's three largest preimplantation genetic diagnosis (PGD) centers. DESIGN: Multicenter analysis of the clinical outcome of PGD. SETTING: In vitro fertilization programs at the Reproductive Genetics Institute, Chicago, Illinois; Saint Barnabas Medical Center, West Orange, New Jersey; and SISMER, Bologna, Italy. PATIENT(S): Poor-prognosis IVF patients, patients carrying balanced chromosomal translocations, and couples at risk for producing children with Mendelian disorders. INTERVENTION(S): In vitro fertilization, intracytoplasmic sperm injection, polar body removal, blastomere biopsy, and ET. MAIN OUTCOME MEASURE(S): DNA or chromosomal analysis of biopsied polar bodies or blastomeres, implantation and clinical pregnancy rates, and live-born pregnancy outcome. RESULT(S): A total of 754 babies have been born as a result of 4,748 PGD attempts, which shows the expanded application and the practical relevance of PGD for single-gene disorders, chromosomal aneuploidies and translocations, late-onset diseases with genetic predisposition, and nondisease testing in couples at need for human leukocyte antigens-matched offspring for treatment of affected siblings. CONCLUSION(S): Preimplantation genetic diagnosis is evolving to become a clinical option for couples at risk for producing offspring with Mendelian diseases, has a positive numerical impact in standard assisted reproduction practices through aneuploidy testing, and reduces by at least fourfold the spontaneous abortion rate in couples carrying translocations.     

植入前遗传学诊断100个周期临床分析

目的 探讨染色体易位对早期胚胎发育的影响,以及植入前遗传学诊断(PGD)技术的诊断效率和可行性.方法 回顾性分析PGD中23个罗伯逊(罗氏)易位周期、19个平衡易位周期(染色体易位组),以及58个α地中海贫血周期(地贫组)共100个周期中的胚胎发育情况、PGD的诊断效率以及临床结局.结果 染色体易位组中有354个胚胎进行PGD,321(90.7%)个胚胎有荧光原位杂交(FISH)结果,其中罗氏易位者中正常和(或)平衡易位胚胎占38.3%(64/167),显著高于平衡易位者的20.8%(32/154).地贫组有537个胚胎进行PGD,单个卵裂球的扩增效率为82.5%(443/537),诊断出正常纯合子140个、杂合子112个、异常纯合子155个、另36个诊断结果不明确,总体诊断效率为75.8%(407/537).染色体易位组中,取卵后第3天卵裂球数≥7的胚胎中,正常和(或)平衡易位发生率(34.4%,77/224)显著高于卵裂球数＜7的胚胎(19.6%,19/97),在取卵后第4天,正常和(或)平衡易位胚胎的细胞融合率为59.4%(57/96),显著高于染色体不平衡胚胎的34.2%(77/225).染色体易位组共在37个周期移植了75个胚胎,获得10例临床妊娠,临床妊娠率27.0%(10/37).地贫组共在58个周期移植了170个胚胎,获得25例临床妊娠,临床妊娠率为43.1%(25/58).结论 PGD技术可有效为染色体易位和地中海贫血基因携带者提供优生选择.染色体易位可能对着床前胚胎的发育有一定的影响.

Abstract：

Objective To investigate influence of chromosomal translocations on early embryo development and to evaluate the efficacy and feasibility of preimplantation genetic diagnosis (PGD)techniques through clinical analysis on PGD cycles. Methods Embryo development, efficacy of PGD and clinical outcome of 100 cycles were studied retrospectively, including 23 cycles with Robertsonian translocations, 19 cycles with reciprocal translocations, and 58 cycles for α-Thalassaemia. Results Among 354 embryos biopsied by PGD for translocations, 321 (90. 7% ) presented fluorescence in situ hybridization (FISH) results. The rate of normal/balanced embryos in the Robertsonian translocation was 38. 3% (64/167),which was significantly higher than 20. 8% (32/154) in the reciprocal translocation group. Amplification was achieved in 443 blastomeres from 537 embryos in Thalassaemia group, which given to an amplification efficiency rate of 82. 5% ( 443/537 ). Totally, 140 normal homozygous, 112 heterozygotes and 155 affected homozygous embryos were identified, while 36 embryos had uncertain result. The successful diagnostic rate was 75.8% (407/537). After 3 days in the translocation groups, the rate of normal and/or balanced translocations in biopsed embryos with ≥7 cells was 34. 4% (77/224), which was significantly higher than 19. 6% ( 19/97 ) of biopsed embryos with ＜ 7 cells. After 4 days, the compaction rate in normal/balanced embryos was 59.4% ( 57/96 ), which was significantly higher than 34. 2% ( 77/225 ) in imbalanced embryos significantly. Seventy-five embryos transferred in 37 cycles with translocations group led to clinical pregnancy rate of 27.0% (10/37), and 170 embryos transferred in 58 cycles with Thalassaemia got a clinical pregnancy rate of 43. 1% ( 25/58 ) . Conclusions PGD can provide management efficiently for both chromosome translocations and Thalassaemia. Translocations might have slightly negative impact on embryo development before implantation.     

应用荧光原位杂交技术进行植入前胚胎染色体诊断的价值

目的 初步探讨应用荧光原位杂交(FISH)技术进行植入前胚胎染色体诊断的价值。方法 对10对不孕夫妇进行植入前遗传学诊断(PGD)周期的超促排卵和卵母细胞浆内单精子注射,于受精后第3天进行胚胎活检及FISH分析,第4天选择染色体组成正常或平衡的胚胎进行移植。结果 10个PGD周期共获卵158个,对其中54个胚胎进行活检,51个胚胎获得明确诊断,诊断率为94％(51／54)。对染色体组成正常或平衡的24个胚胎进行官腔内移植,共4例获得妊娠,其中3例已足月分娩健康婴儿,1例为异位妊娠。结论 应用FISH技术进行植人前胚胎染色体诊断,是预防流产和染色体异常患儿出生的有效手段。     

Preimplantation genetic diagnosis for beta-thalassaemia: the Sardinian experience

OBJECTIVES: To report the experiences on preimplantation genetic diagnosis (PGD) in couples at risk for beta-thalassaemia in Sardinia. METHODS: 23 couples at risk for beta-thalassaemia were included in the PGD programme with a total of 42 cycles performed. Among these, 11 couples were fertile, while the remaining 12 had associated fertility problems. In vitro Fertilization (IVF), PGD and prenatal genetic molecular confirmation protocols and results are reported. RESULTS: All the patients followed the protocol of ovarian stimulation, oocyte retrieval, intracytoplasmic sperm injection (ICSI), embryo biopsy and genetic analysis. A total of 272 oocytes were fertilized in the regular way, and embryo biopsy was performed on 202 embryos. Out of these 202 embryos, 192 (95%) were successful. The genetic diagnosis was performed on 150 embryos (78.1%). Ninety-eight were identified as unaffected and 75 were transferred in 31 cycles. In the infertile patient group, two biochemical pregnancies (11.1% per transfer), in the fertile patient group, four clinical pregnancies, two twin and two singleton pregnancies (30.8% per transfer), were obtained. The genetic molecular results were confirmed in all pregnancies by first-trimester chorionic villus sampling (CVS). CONCLUSION: Our study shows that PGD for beta-thalassaemia is an available procedure for couples who wish to avoid termination of pregnancy, except in cases where the IVF cycle efficiency is very poor.     

Chromosomal Analysis of Pre-implantation Embryos: Its Place in Current IVF Practice

BackgroundThe intersection of ART and molecular genetic science is fast growing. It is now possible to utilize the advances in molecular genetics for clinical application to detect chromosomal aberrations in preimplanting embryos.As molecular genetic techniques have improved, it is now possible to test the complete characterization of human genome variation with reasonable accuracy. In this article, we have tried to summarize the common current indications of chromosomal analysis of preimplanting embryos in couples having various chromosomal dominant or chromosomal recessive heritable disorders leading to the birth of a new born baby with chromosomal aberrations or leading to repeated miscarriage.ConclusionThe currently available techniques of embryo biopsy have their advantages and shortcomings. Today, preimplantation genetic testing to diagnose a euploid embryo is widely used in clinical practice in couples undergoing IVF ET treatment. By eliminating the transfer of aneuploid embryos, the pregnancy rate improves per embryo transfer and it shortens the time of conception from the start of IVF treatment. We have also discussed the current scenario of the place of PGT-A for routine use in IVF treatment procedure in view of the possible risk of losing euploid embryos due to the shortcoming of the embryo biopsy procedure.     

Current features of preimplantation genetic diagnosis

More than 4000 preimplantation genetic diagnosis (PGD) cycles have been performed, suggesting that PGD may no longer be considered a research activity. The important present feature of PGD is its expansion to a variety of conditions, which have never been considered as an indication for prenatal diagnosis, including the late-onset disorders with genetic predisposition and preimplantation non-disease testing, with the further improvement of the accuracy of PGD for single gene disorders. PGD has also become a useful tool for the improvement of the effectiveness of IVF, through avoiding the transfer of chromosomally abnormal embryos, representing more than half of the embryos routinely transferred in IVF patients of advanced maternal age and other poor prognosis patients. PGD is of particular hope for the carriers of balanced chromosomal translocations, as it allows accurate pre-selection of a few balanced or normal embryos resulting from the extremely poor meiotic outcome, especially in reciprocal translocations. With the current progress in polymerase chain reaction- (PCR-) based detection of chromosomal abnormalities in oocytes and embryos, PGD may soon be performed for both chromosomal and single gene disorders using the same biopsied polar body or blastomere, frequently required with the currently expanded PGD application. The available clinical outcome data of more than 3000 PGD embryo transfers further suggest an acceptable pregnancy rate and safety of the procedure, as demonstrated by the follow-up information available for more than 500 children born from these PGD transfers.     

Comparison of intracytoplasmic sperm injection with testicular spermatozoa success in infertile men with obstructive and non-obstructive azoospermia; a retrospective analysis

The aim of this study was to compare the outcome of intracytoplasmic sperm injection (ICSI) and embryo transfer between couples with infertility due to male non-obstructive azoospermia (NOA) and obstructive azoospermia (OA). A retrospective analysis of 234 couples with azoospermia who were treated by ICSI and embryo transfer between January 2007 and October 2010 was performed. There were 61 couples in NOA group and 173 couples in OA group. Fertilization rates, pregnancy and clinical pregnancy rates were the main outcome measures. The number of retrieved mature oocytes, injected oocytes, metaphase II (MII) oocytes, two distinct pronuclei oocytes, cleavage embryos and embryos transferred was not significantly different between the groups. The fertilization rate was significantly lower in NOA group when compared to OA group (56.2 vs. 66.7%, respectively; p?=?0.013) and the pregnancy rate was significantly lower in NOA group than OA group (36.1 vs. 50.9%, respectively; p?=?0.046). The clinical pregnancy rates were not statistically different between the patients with NOA and OA azoospermia groups (24.6 vs. 36.4%, respectively; p?=?0.09). This study suggests that ICSI and embryo transfer together with testicular sperm extraction results in statistically significant lower fertilization and pregnancy rates in men with NOA when compared to men with OA.     

Assessing the clinical utility of in vitro fertilization with intracytoplasmic sperm injection in human immunodeficiency virus type 1 serodiscordant couples: report of 113 consecutive cycles

OBJECTIVE: To assess the utility and safety of in vitro fertilization (IVF) with intracytoplasmic sperm injection (ICSI) in human immunodeficiency virus-1 (HIV-1) serodiscordant couples. DESIGN: Retrospective study. SETTING: University-based practice. PATIENT(S): HIV-1 seropositive men and seronegative women undergoing IVF-ICSI.IVF-ICSI, HIV testing of female partner and infants. MAIN OUTCOME MEASURE(S): IVF performance, pregnancy rates, and HIV-1 seroconversion rate. RESULT(S): We initiated 113 IVF cycles in 61 serodiscordant couples. Due to poor ovarian response, 11.5% of cycles were canceled. The number of oocytes collected per retrieval was 17.11 +/- 9.52 (2 to 47), yielding 13.90 +/- 8.12 (1 to 42) mature oocytes suitable for ICSI, and 9.34 +/- 5.45 (0 to 24) normal fertilized oocytes. We transferred 3.54 +/- 1.09 (1 to 6) embryos. The overall clinical pregnancy rate was 44.8% per embryo transfer (ET); ongoing/delivered pregnancy rate was 36.5% per ET, with a 57.1% multiple gestation rate. Cumulatively, 50.8% of couples achieved a successful pregnancy through IVF-ICSI, 54.1% when including frozen ET cycles. There were no HIV-1 seroconversions in patients or delivered babies. CONCLUSION(S): HIV-1 serodiscordant couples who undergo IVF-ICSI to avoid disease transmission experience high rates of success, but also encounter complications from assisted reproductive technology similar to traditional patients. The best candidates appear to be younger women without strong risk factors for ovarian hyperstimulation syndrome.     

引物延伸预扩增法应用于β-地中海贫血患者胚胎植入前遗传学诊断--附一例报告

目的 探讨对β-地中海贫血进行胚胎植入前遗传学诊断(PGD)的方法。方法 两对夫妇双方均分别为密码子41-42(-TCTT)及插入序列(IVS)-Ⅱ654(c→T)突变杂合子,在本中心进行超排卵和体外受精-胚胎移植治疗,胚胎活检后应用全基因组扩增技术及反向点杂交进行胚胎PGD,根据诊断结果选择健康的胚胎移植入子宫。结果 2例患者共获卵35个,受精率为87％,共活检胚胎16个,获卵裂球25个,单卵裂球总扩增效率为84％,等位基因脱扣率为15％。2例患者共移植5个胚胎,1例获得妊娠,已分娩健康双胎。结论 应用引物延伸预扩增技术可对β-地中海贫血进行PGD,达到优生的目的。     

Morphological aspect of embryos obtained after fertilization in vitro for male factor or ICSI

OBJECTIVE: In order to study the eventual impact on fertilization and embryo characteristics of the microinjection procedure we compared the quality of the embryos obtained by ICSI with those of in vitro fertilization with male factors (MF IVF). MATERIAL AND METHODS: One hundred thirty-four cycles of IVF treatment (group 1) were selected with oligoasthenozoospermia according to WHO criteria with a total number of motile spermatozoa between 500,000 and 1 million. One thousand eighty-eight mature oocytes and 486 embryos were obtained. One hundred forty-three cycles of intracytoplasmic sperm injection (group 2) were performed in couples whose in vitro fertilization was imparticable because of extreme sperm impairment. One thousand one hundred forty-seven mature oocytes were injected and 626 embryos were obtained. RESULTS: In group 1, the pregnancy rate per embryo transfer and the implantation rate were respectively 22.7% and 12.3%. In group 2, the pregnancy rate per embryo transfer was 37.1% and the implantation rate was 17%. The statistical analysis of the embryos obtained in the two different groups did not demonstrate any difference in the distribution of the more regular and less fragmented embryos (group A) and those of the more irregular and fragmented embryos (group B). No statistical difference was demonstrated in the chronology of the division of these embryos (groups 1 and 2). CONCLUSION: The pregnancy rate by cycle and by transfer reported by ICSI (p < 0.003 and p < 0.015 respectively) could be related to a significantly higher mean number of transferred embryos (2.65 vs 2.02) in probable relation with a higher cleavage rate (p < 0.00001).     

获卵数目对有效胚胎形成率的影响:2578个体外受精周期分析

目的探讨体外受精/卵胞质内单精子注射-胚胎移植(IVF/ICSI-ET)中影响可用胚胎率的主要因素。方法回顾性分析行IVF/ICSI-ET治疗的2 578个周期共24 772枚卵母细胞。按获卵数将其分为A组(1~5)、B组(6~10)、C组(11~15)、D组(16~20)、E组(20),比较各组的受精率、卵裂率、MⅡ卵率、有效胚胎形成数(率)、妊娠率及胚胎种植率等。采用多因素线性回归分析筛选出影响受精率、卵裂率、卵子成熟率以及可用胚胎数(率)的独立相关因素,同时排除单因素分析中出现的混杂。结果单因素分析各组卵子成熟卵率有差异,但没有看到趋势性变化;IVF受精率在各组间有统计学差异,而ICSI受精率各组间无统计学差异。卵裂率各组间无统计学差异,可用胚胎数以及冷冻胚胎数A~E组依次增加,而可用胚胎率随着获卵数的增加却逐渐降低(44.6%、36.0%、33.5%、29.4%、28.8%,P=0.00)。多因素分析提示取卵数的标准化回归系数的绝对值最大(B=-0.205,P=0.00),t的绝对值也最大(t=-8.299),表明取卵数对可用胚胎率的影响最大,提示取卵数越多,可用胚胎率越低。而卵子数目对卵子成熟率、受精率以及卵裂率没有影响。结论随着取卵数的增多,虽然可用胚胎数是增加的,但可用胚胎的转化率却降低了。今后的促排卵目标不是产生的卵子越多越好,而是采用合适的方案尽量减少对卵巢的过度刺激,获得一定数量的正常卵子并形成优质的可供移植的胚胎。     

Chromosomal characteristics at cleavage and blastocyst stages from the same embryos

Purpose

To investigate chromosomal characteristics in the same embryos at cleavage and blastocyst stage.

Methods

Six PGD/PGS cycles were retrospective studied, including five chromosomal translocation PGD cycles and one recurrent abortion PGS cycle. The cleavage embryos were biopsied one blastomere at day 3, followed by blastocyst culture. Trophectoderm cell biopsy was performed when embryos developed into the blastocyst stage. Whole genome amplification and 24-chromosomal analysis by CGH/SNP microarray was performed on each blastomere and trophectoderm cells.

Results

After PGD/PGS, only one couple had no euploid embryos to transfer. Five couples delivered a healthy, balanced-karyotype baby. A total of 18 embryos had both blastomere and trophectoderm cell reliable results available. Of the 18 embryos, eleven embryos contained identical chromosomes from cleavage stage to blastocyst stage and six embryos contained almost identical chromosomes . Only one embryo presented opposite chromosomal results for the cleavage and blastocyst stage, with abnormal chromosomes in the blastomere but normal chromosomes in trophectoderm cells.

Conclusions

Most embryos maintain chromosomal stability during embryonic development. Compared to cleavage stage, blastocyst stage may provide more reliable aneuploidy results.     

Embryo development characteristics in Robertsonian and reciprocal translocations: a comparison of results with non-translocation cases

The effect of translocations on embryo development was evaluated and results were compared in terms of embryo development with those of embryos obtained from standard intracytoplasmic sperm injection (ICSI) cycles. In 23 translocation carriers with 34 cycles, fertilization, pronuclear morphology scoring (PMS), developmental arrest, cleavage and blastocyst formation were evaluated and compared with embryos obtained from non-translocation cases undergoing ICSI (n = 98 cycles). In 28 cycles, preimplantation genetic diagnosis (PGD) was performed on prezygotes (first and second polar body biopsy for female carriers; n = 3) or on embryos having seven or more blastomeres (blastomere biopsy; n = 25). In six cycles for four couples, probes for translocated chromosomes were not available, so PGD could not be performed. Overall, in translocation cases, a lower fertilization rate, a higher rate of retarded embryo development, and a lower rate of blastocyst formation were observed compared with embryos of non-translocation cases. Fluorescence in-situ hybridization (FISH) analysis showed a 70.9% abnormality rate for reciprocal translocations and 55.0% for Robertsonian translocations respectively. In cases with Robertsonian and reciprocal translocation carriers, the probability of poor embryo development, which may be a result of high segregation abnormalities, may negatively affect the outcome of assisted reproductive techniques. This poor prognosis should also be considered when genetic counselling for translocation is given.