Subfertile men with constitutive chromosome abnormalities do not necessarily refrain from intracytoplasmic sperm injection treatment: a follow-up study on 75 Dutch patients

A follow-up study was performed to investigate the impact of the detection of a chromosome abnormality in infertile men who are candidates for intracytoplasmic sperm injection (ICSI) treatment. In this collaborative study between clinical genetics centres and fertility clinics in the Netherlands, 75 ICSI couples of which the male partners had a chromosome abnormality were included. All couples were extensively counselled on the risk of having a chromosomally unbalanced child. Forty-two out of 75 couples chose to proceed with the ICSI treatment. So far, treatment has resulted in a pregnancy in 11 cases. Four of them opted to have invasive prenatal diagnosis. Despite the genetic risks related to a chromosome abnormality in infertile men, a small majority (56%) of the couples did not refrain from the ICSI treatment.     

Investigation of confined placental mosaicism (CPM) at multiple sites in post-delivery placentas derived through intracytoplasmic sperm injection (ICSI)

Although earlier studies on pregnancies derived through intracytoplasmic sperm injection (ICSI) reported increased non-mosaic aneuploidy among ICSI children, undetected mosaicism, such as confined placental mosaicism (CPM) has not been evaluated. We investigated the incidence of CPM in post-delivery placentas derived from ICSI, evaluated whether CPM was increased and whether it was a contributing factor to negative pregnancy outcome. [Fifty-one post-delivery placentas were collected from patients who underwent ICSI with a normal or negative pregnancy outcome]. Trophoblast and chorionic stroma from three sites were analyzed by comparative genomic hybridization (CGH) and flow cytometry. Detected abnormalities were confirmed by fluorescence in situ hybridization (FISH). The incidence of CPM in the ICSI population was compared to the general population from published data. We detected three cases of CPM in our study. One abnormality was found by CGH analysis; partial trisomy 7q and a partial monosomy Xp limited to the trophoblast at two sites. The abnormality was associated with a child affected by spina bifida. Two cases of mosaic tetraploidy were observed by flow cytometry in pregnancies with a normal outcome. All three abnormalities were confirmed by FISH analysis. The incidence of CPM in the ICSI study population was 5.88% (3/51), which was not statistically different from published reports in the general population (5.88% (42/714), Chi square, P > 0.05). The post-ICSI population was not at risk for CPM in this study.     

An association between sex chromosomal aneuploidy in sperm and an abortus with 45,X of paternal origin: possible transmission of chromosomal abnormalities through ICSI

BACKGROUND: Although it has been speculated that the increased de-novo chromosomal abnormalities in ICSI pregnancies may be associated with an increase of aneuploidy in sperm from infertile men, little direct evidence exists to support this claim. We studied sperm from an infertile man with an abortus from ICSI to determine if increased sex chromosomal aneuploidy in the sperm could have contributed to the karyotype of the abortus. METHODS: The couple underwent ICSI due to severe oligozoospermia. Spontaneous aborted material was subjected to cytogenetic and molecular tests to ascertain the existence, type and origin of a chromosomal abnormality. Sperm from the man were analysed by multi-coloured fluorescent in-situ hybridization (FISH) with probes specific for chromosomes X, Y and 18. RESULTS: At 8+ weeks after embryo replacement, the patient spontaneously miscarried. Both cytogenetic and comparative genomic hybridization analysis of aborted material showed a 45,X karyotype. Origin of the abnormality was established as a loss of the paternal X chromosome. FISH analysis of sperm revealed 19.6% (1990/10,164) nullisomy for a sex chromosome and 18.6% (1886/10,164) with XY disomy, which is significantly increased when compared to controls with 0.3% (58/20,429) and 0.1% (20/20,429) respectively (P<0.0001). CONCLUSIONS: This study indicates that the paternal origin of the 45,X abortus was likely the result of a high level of nullisomy in the sperm and provides evidence for the transmission of chromosomal abnormality from sperm to the conceptus through ICSI.     

Success of intracytoplasmic sperm injection in couples with male and/or female chromosome aberrations

This paper reports on results of intracytoplasmic sperm injection (ICSI) in patients in whom constitutional or secondary chromosome aberrations were detected in the male and/or female partner. Out of 434 couples treated by ICSI (590 cycles), 16 couples (3.7%) were affected by constitutional chromosome aberrations and 96 (22.1%) by secondary chromosome aberrations. Constitutional chromosome aberrations were found in eight male and eight female patients. Couples with the aberration in the male showed significantly lower fertilization, implantation and pregnancy rates (P < 0.05). The occurrence of female constitutional chromosome aberrations led to lower fertilization rates but implantation and pregnancy rates were similar to a control group; however, a higher abortion rate was noted. In the group with secondary chromosome aberrations, 22 males and 59 females carried an abnormality and in 15 couples, both partners. Compared to the remaining (unaffected) 322 couples, fertilization and embryo transfer rates were reduced but implantation rates and pregnancy rates were not different. In all couples where an abortion occurred, mainly parental autosomal aberrations were involved (six out of eight). Our retrospective analysis shows that an unexpectedly high number of infertile couples in an ICSI programme are affected by chromosome aberrations, which in turn may explain the reduced fertilization rates observed in this subgroup of patients.      

Surgical sperm retrieval and intracytoplasmic sperm injection as treatment of obstructive azoospermia

Male genital tract obstructions may result from infections, previous inguinal and scrotal surgery (vasectomy) and congenital bilateral absence of the vas deferens (CBAVD). Microsurgery can sometimes be successful in treating the obstruction. In other cases and in cases of failed surgical intervention, the patient can be treated by microsurgical or percutaneous epididymal sperm aspiration (MESA, PESA) or testicular sperm extraction (TESE) and intracytoplasmic sperm injection (ICSI). We present the results of 39 ICSI procedures for obstructive azoospermia in 24 couples. The aetiology of the obstruction was failed microsurgery in 11 patients, CBAVD in nine and genital infections in four. Sperm retrieval was accomplished via MESA in four cases, PESA in 18 cases and via TESE in 11 cases. TESE was only applied when PESA failed to produce enough spermatozoa for simultaneous ICSI. In six patients, the ICSI procedure was performed with cryopreserved spermatozoa after an initial PESA procedure. Fertilization occurred in 47% of the metaphase II oocytes; embryo transfer was performed in 92% of procedures and resulted in a clinical pregnancy in 13/39 procedures. Ongoing pregnancy was achieved in 10/39 procedures. One pregnancy was terminated early after prenatal investigation showed a cytogenetic abnormality (47,XX+18, Edwards syndrome). The other nine pregnancies resulted in the live birth of 10 children, without any congenital abnormalities. Epididymal and testicular retrieved spermatozoa were successfully used for ICSI to treat obstructive azoospermia, and resulted in an ongoing pregnancy in 10 of 24 couples (41.6%) after 39 ICSI procedures, a success rate of 25.6% per treatment cycle and of 27.7% per embryo transfer.      

Achievement of pregnancy in globozoospermia with Y chromosome microdeletion after ICSI

Pregnancy achieved with sperm from a patient with globozoospermia is rare, even after ICSI, since the activation of the oocyte may not occur in this disorder. Therefore, activation of the oocytes by piezoelectricity or calcium ionophores has been suggested, although spontaneous activation of the oocyte after ICSI has been reported in some cases. We report a successful pregnancy in a couple in which the male partner had globozoospermia with microdeletions in the Y chromosome with no further assisted activation after ICSI. During the diagnostic study of the husband, increased numerical chromosome abnormalities after fluorescent in-situ hybridization (FISH) and microdeletions in AZFa; sY86 and AZFb; sY 131 were detected. Out of the 13 oocytes injected, four fertilized and a twin pregnancy was obtained after replacement of four embryos. Healthy twin girls were delivered after a term pregnancy. Some patients with globozoospermia may also have Y chromosome microdeletions, which subsequently may be inherited by the male offspring in cases of achievement of pregnancy.     

Cellular and genetic analysis of oocytes and embryos in a human case of spontaneous oocyte activation

Unusual and consistent defects in infertility patients merit attention as these may indicate an underlying genetic abnormality, in turn necessitating tailored management strategies. We describe a case of repeated early pregnancy loss from in vivo conceptions, followed by cancelled embryo transfers after one IVF and one ICSI/PGD cycle. Following the unexpected presence of cleaved embryos at the fertilization check in the first IVF attempt, oocytes and embryos were subsequently analyzed in an ICSI/PGD case. Part of the oocyte cohort was fixed at retrieval for a cellular evaluation of microtubules, microfilaments and chromatin. The remaining oocytes were injected with sperm, and resultant embryos were biopsied for genetic analysis by fluorescence in situ hybridization (FISH), single-nucleotide polymorphism (SNP) microarray for 23 chromosome pairs, as well as with PCR for sex chromosomes. The presence of interphase microtubule networks and pronuclear structures indicated that oocytes were spontaneously activated by the time of retrieval. FISH revealed aneuploidy in all seven blastomeres analyzed, with all but two lacking Y chromosomes. Microarray SNP analysis showed an exclusively maternal origin of all blastomeres analyzed, which was further confirmed by PCR. From our multi-faceted analyses, we conclude that spontaneous activation, or parthenogenesis, was probably the pathology underlying our patient's recurrent inability to maintain a normal pregnancy. Such analyses may prove beneficial not only in diagnosing case-specific aberrations for other patients with similar or related failures, but also for furthering our general understanding of oocyte activation.     

Maternal origin of monosomy 21 derived from ICSI

With the worldwide diffusion of the intracytoplasmic sperm injection (ICSI) procedure in recent years, the issue of possible genetic risks of this new and powerful technique has attracted considerable attention. An important concern is whether ICSI facilitated the passage of genetic defects from spermatozoa to offspring. ICSI was performed with spermatozoa from a frozen-thawed sperm sample from a testicular sperm extraction (TESE) of a 38 year old man who suffered from azoospermia. His wife was 36 years old. The resulting pregnancy spontaneously aborted at 8 weeks gestation after embryo replacement. Cytogenetic investigation displayed monosomy 21. The paternal origin of the single chromosome 21 was determined by molecular analysis. The segregation error leading to loss of one chromosome 21 is likely to have occurred during oogenesis rather than as a direct consequence of ICSI. Nonetheless, monosomy 21 is extremely rare and it cannot be excluded that ICSI assisted the fertilization of an abnormal oocyte.     

Genetics: Intracytoplasmic sperm injection in infertile patients with structural chromosome abnormalities

In the present study we investigated the results of cyto-geneticanalysis in male and female patients included in an intracytoplasmicsperm injection (ICSI) programme for severe male infertilityas well as in conceptuses resulting from these ICSI treatments.In the 261 couples treated, 11 male (4.2%) and three female(1.2%) abnormal karyotypes were found, all consisting of structuralchromosome anomalies. Chromosomal translocation exhibited thehighest frequency (eight males and two females), and there werealso three cases of chromosomal inversion (two males and onefemale) and one male with one additional marker chromosome.There was no difference in fertilization rates among coupleswith abnormal (n = 14) and normal (n = 147) cytogenetic results,and the rates of clinical pregnancy per ICSI attempt were 25.0%(5/20) and 20.6% (78/378) respectively. In pregnancies obtainedin couples with normal karyotypes, all of the 108 fetuses werefree of chromosomal abnormalities. Among the eight fetuses fromcouples with chromosome structural anomalies, three out of fiveand two out of three inherited the cytogenetic defects foundin their father or mother respectively. In this series of 83ICSI pregnancies there were no chromosomal abnormalities otherthan those inherited from the parents. These findings suggestthat normal pregnancy rates can be obtained by ICSI in casesof chromosomal translocation in couples with severe male infertility.However, until further evaluations of available data can beperformed, cytogenetic analysis must be conducted prior to ICSIin men with low sperm counts, and genetic counselling must includeprenatal diagnosis for all growing conceptuses.     

卵胞浆内单精子显微注射治疗男性不育的临床应用

目的 应用卵胞浆内单精子显微注射(intracytoplasmic spern injection,ICSl)技术治疗因严重少。弱精及阻塞性无精症引起的男性不育。方法 74对不育夫妇经遗传咨询、染色体检查、Y染色体．AZF基因分析、体检及生殖激素测定等。女方采用控制性超排卵技术获得卵子。男方少、弱精患者精液采用梯度离心法分离精子。阻塞性无精症患者采用经皮附睾穿刺或睾丸活检获得精子，选择成熟卵子行单精子显微注射。结果 82个治疗周期中共获卵837个，其中成热卵712个。ICSI后603个卵受精，受精率为84．69％，发生卵裂．563个。卵裂率为93．37％。42w期获临床妊娠，临床妊娠率为51．12％。结论 ICSl技术是治疗男性不育的有效方法。患者接受治疗前应进行必要的遗传学检查和严格的遗传咨询。     

Cytogenetic changes in Wilms' tumors

Cytogenetic analysis of 20 Wilms' tumors using short-term culture techniques were undertaken. Chromosome abnormalities were detected in all tumors. In 19 of 20 cases only minor karyotypic changes were observed within cells with near-diploid chromosome numbers; only one tumor was predominantly hyperdiploid. Rearrangements involving chromosome 1 were the most frequently observed abnormality (in 25%) and often resulted in partial or complete trisomy for the long arm. In 20% of the tumors, abnormalities involving chromosomes 11 and 16 were present. The only other chromosomes frequently involved in structural or numerical changes were #12, and #18. Two discrete tumor foci within the same kidney differed cytogenetically, suggesting an independent origin for each focus. No correlation could be made between specific chromosome abnormalities and tumor stage or histologic subtype. Although constitutional deletion of chromosome region 11p13 has frequently been reported to predispose to Wilms' tumor formation, only two tumors with deletions involving this region were observed. Chromosomes from tumors treated with chemotherapy prior to surgical removal and culture yielded findings similar to those in untreated tumor cells.     

Prenatal diagnosis of a fetus with two balanced de novo chromosome rearrangements

Two apparently balanced chromosome rearrangements were identified in a 17-week fetus by analysis of cultured amniocytes. The fetal karyotype was 46,XX,t(2;16) (q33; q24), inv(7)(p15q11.23). Parental karyotypes were normal, indicating a de novo origin of both chromosome rearrangements in the fetus. The risk of phenotypic abnormality from a de novo reciprocal translocation or inversion has been estimated at approximately 7% [Warburton, 1991]. The risk of abnormality in this fetus was estimated to be a minimum of 14%, based on the additive risk of each rearrangement, equivalent to 3.5% per chromosome breakpoint. The pregnancy was terminated because of the risk of abnormality and the detection of intrauterine growth retardation by ultrasound. In the absence of additional experience, the minimum presumed risk of phenotypic abnormality for de novo, multiple or complex chromosome rearrangements identified prenatally may be estimated as the additive risk of the number of chromosome breakpoints involved. © 1996 Wiley-Liss, Inc.     

Andrology: Fertilizing ability of immotile spermatozoa after intracytoplasmic sperm injection

Sometimes spermatozoa from ejaculate, epididymis or testis showa total absence of motility. For some patients, however, veryfew spermatozoa with very poor motility can be found after severalhours of incubation (initially immotile spermatozoa). Othersamples show no motility at all even after extended culture(totally immotile spermatozoa). Intracytoplasmic sperm injection(ICSI) is the only method available to select and retrieve asingle immotile or initially immotile spermatozoon and injectit into the oocyte. A total of 103 patients with asthenozoospermiaunderwent ICSI in this study. It was shown that initially immotileand totally immotile spermatozoa, whatever their origin, havethe capacity to fertilize an oocyte after ICSI. No significantdifference could be observed between the fertilizing capacityof testicular or epididymal spermatozoa. Totally immotile ejaculatedspermatozoa, however, fertilized significantly fewer oocytesafter ICSI when compared with initially immotile ejaculatedspermatozoa. Embryos of lower quality tended to be producedwhen totally immotile spermatozoa of any origin were used, comparedwith embryos resulting from initially immotile spermatozoa.Ongoing pregnancies were conceived after ICSI with initiallyimmotile spermatozoa from any origin and totally immotile spermatozoaretrieved from testis only. One biochemical pregnancy was theresult of embryo transfer after ICSI with totally immotile ejaculatedspermatozoa. No supernumerary embryos could be cryo-preservedfor patients with totally immotile spermatozoa from ejaculateor epididymis. For a Kartagener patient, subzonal insemination(SUZI) seemed to be a better approach for obtaining fertilizationand pregnancy than ICSI because no fertilization occurred afterICSI on sibling oocytes. Hence a healthy pregnancy was obtainedafter SUZI.     

Cytogenetic and molecular genetic characterization of papillary thyroid carcinomas.

A combined cytogenetic and molecular analysis was performed on 11 cases of papillary thyroid carcinoma. A simple karyotypic abnormality was detected in five tumors, whereas six had no apparent chromosome change. In four of five rearranged cases the presence of a specific chromosomal abnormality involving chromosome 10 (cases 1 and 2) and chromosome 1 (cases 3 and 4) was associated with the rearrangement of two protooncogenes: RET and NTRKI (formerly trk), respectively, with different donor genes. Moreover, the chromosomal localization of the involved genes and the type of chromosomal change observed suggested that RET and NTRKI activation occurred by intrachromosomal rearrangements. The six cases with normal karyotype did not show RET or NTRKI activation. These findings suggest that a combined cytogenetic and molecular approach would be useful in understanding the pathogenesis of thyroid neoplasia.     

2473例双胎妊娠的无创产前检测结果分析

目的分析探讨无创产前检测(non-invasive prenatal testing,NIPT)对于双胎妊娠胎儿非整倍体的检测价值。方法选取2016年1月至2019年12月在本中心接受NIPT检测的2473例双胎孕妇,利用高通量测序和生物信息学分析测算胎儿染色体非整倍体的风险率,为高风险孕妇提供羊膜腔或绒毛穿刺,并对结果进行随访。结果在2473例孕妇中,共检出31例(1.25%)胎儿染色体高风险,其中5例为21-三体,1例为21号染色体缺失,4例为18-三体,7例为性染色体异常,14例为微缺失/微重复。经产前诊断或新生儿外周血染色体核型分析,共确诊5例21-三体、3例18-三体,1例性染色体异常,2例微缺失/微重复,其阳性预测值分别为100%、75%、25%和25%。结论NIPT筛查双胎妊娠胎儿染色体非整倍体的准确性较高,是一种安全有效的筛查手段,对21-三体的筛查效率高于其他染色体。     

Combined spectral karyotyping and DAPI banding analysis of chromosome abnormalities in myelodysplastic syndrome.

Spectral karyotyping (SKY) is a new molecular cytogenetic technique that allows simultaneous visualization of each chromosome in a different color. We have used SKY for comprehensive analysis of 20 myelodysplastic syndromes (MDSs) (13 primary MDSs, 3 therapy-related MDSs, and 4 acute leukemias developed from MDS, including 1 cell line established from a secondary leukemia), previously analyzed by G-banding. To locate the chromosomal breakpoints, DAPI-counterstained band images from all metaphases were transformed to G-band-like patterns. By using SKY, it was possible to identify the origin and organization of all clonal marker chromosomes (mar), as well as the origin of all abnormalities defined as additional material of unknown origin (add) or homogeneously staining regions (hsr) by G-banding. In total, SKY identified the chromosomal basis of 38 mar, add, and hsr, corrected 8 abnormalities misidentified by G-banding, and revealed 6 cryptic translocations in 5 cases. Total or partial chromosomal loss (mainly of -5/5q- and -7/7q-) is the most frequent cytogenetic abnormality in MDS. In 3 of 11 cases with -5/5q- and in 4 of 8 with -7/7q-, lost material was detected by SKY in unbalanced translocations. A total of 60 chromosomal losses were identified by G-banding in 16 cases with multiple chromosome abnormalities involving at least 3 chromosomes. For 26 of these losses (43%), SKY analysis suggested that the losses were not complete, but had been translocated to a variety of partner chromosomes. Moreover, SKY analysis revealed that a ring chromosome in a case of acute leukemia developed from MDS contained three to six segments that originated from chromosome 21 material. Fluorescence in situ hybridization showed the amplification of the AML1 gene on regions derived from chromosome 21, providing the first evidence of amplification involving this gene in MDS. Genes Chromosomes Cancer 26:336-345, 1999.     

Neonatal data on a cohort of 2889 infants born after ICSI (1991-1999) and of 2995 infants born after IVF (1983-1999)

BACKGROUND: To evaluate the safety of ICSI, this study compared data of IVF and ICSI children by collecting data on neonatal outcome and congenital malformations during pregnancy and at birth. METHODS: The follow-up study included agreement to genetic counselling and eventual prenatal diagnosis, followed by a physical examination of the children after 2 months, after 1 year and after 2 years. 2840 ICSI children (1991-1999) and 2955 IVF children (1983-1999) were liveborn after replacement of fresh embryos. ICSI was carried out using ejaculated, epididymal or testicular sperm. RESULTS: In the two cohorts, similar rates of multiple pregnancies were observed. ICSI and IVF maternal characteristics were comparable for medication taken during pregnancy, pregnancy duration and maternal educational level, whereas maternal age was higher in ICSI and a higher percentage of first pregnancies and first children born was observed in the ICSI mothers. Birthweight, number of neonatal complications, low birthweight, stillbirth rate and perinatal death rate were compared between the ICSI and the IVF groups and were similar for ICSI and IVF. Prematurity was slightly higher in the ICSI children (31.8%) than in the IVF children (29.3%). Very low birthweight was higher in the IVF pregnancies (5.7%) compared with ICSI pregnancies (4.4%). Major malformations (defined as those causing functional impairment or requiring surgical correction), were observed at birth in 3.4% of the ICSI liveborn children and in 3.8% of the IVF children (P = 0.538). Malformation rate in ICSI was not related to sperm origin or sperm quality. The number of stillbirths (born > or =20 weeks of pregnancy) was 1.69% in the ICSI group and 1.31% in the IVF group. Total malformation rate taking into account major malformations in stillborns, in terminations and in liveborns was 4.2% in ICSI and 4.6% in IVF (P = 0.482). CONCLUSIONS: The comparison of ICSI and IVF children taking part in an identical follow-up study did not show any increased risk of major malformations and neonatal complications in the ICSI group.     

Sperm chromosome analysis to assess potential germ cell mosaicism

Human sperm chromosome complements were examined to assess the possibility that the conceptions of two children with the same chromosomal defect, del(13)(q22q32), from chromosomally normal parents were the result of a paternal germ cell mosaicism. Analysis of 216 complements, both by quinacrine banding and by measuring the relative length of chromosome 13, showed no unusual subpopulation of 13s; this decreased the likelihood of a paternal origin of the deletion. Sperm chromosomal analysis is a useful adjunct to available techniques in clinical genetics. When counseling cases involving either structural or numerical de novo chromosome abnormality, it is of importance to discuss the possibility of germ cell line mosaicism as well as to offer prenatal diagnosis for subsequent pregnancies.     

Significance of abnormalities involving chromosomal segment 11q22-25 in acute leukemia

Six hundred and thirty unselected cases of acute leukemia, with complete data regarding age, karyotype (with breakpoints), and the diagnosis according to the FAB classification, were available in the literature and from our unpublished cases for comparing the incidence of chromosomal abnormalities involving the long arm of chromosome #11 among age groups in acute nonlymphocytic leukemia (ANLL) and acute lymphocytic leukemia (ALL). A statistically highly significant difference (p less than 0.001) was observed between the incidence of ANLL cases with chromosome aberrations involving 11q22-25 in childhood (less than or equal to 15 years) versus that in adults (greater than 15 yr). This statistical difference was not only related to infant cases (less than or equal to 12 months), but also to cases of children over 1 year of age. The incidence of the 11q22-25 abnormality in childhood cases (greater than 1 yr to less than or equal to 15 yr) was statistically significant (0.025 less than p less than 0.05) when compared to the incidence in adult cases. The incidence of the 11q22-25 abnormality in infant cases was much higher when compared to that of older cases with either ANLL or ALL (p less than 0.001 in each leukemia). This trend was not observed in cases with the 11q11-21 abnormality and this may imply that the origin and meaning of the 11q11-21 abnormality may differ from that of the 11q22-25 abnormality. Twenty-three infants with acute leukemia (AL) with the 11q22-25 abnormality were available from previous reports and our unpublished case. The median ages of ANLL, ALL, and all AL cases were 16 weeks, 9 weeks, and 15 weeks, respectively. The tendency of the 11q22-25 abnormality to be common in infants with ANLL or ALL under 6 months of age may suggest that it has a close correlation with the origin(s) or mechanism(s) related to the occurrence of infant AL.     

Fertilization, pregnancy and embryo implantation rates after ICSI in cases of obstructive and non-obstructive azoospermia

The aetiology of azoospermia can be grossly divided into obstructive and non-obstructive causes. Although in both cases testicular spermatozoa can be used to treat male fertility, it is not well established whether success rates following intracytoplasmic sperm injection (ICSI) are comparable. Therefore, a retrospective analysis of fertilization, pregnancy and embryo implantation rates was performed following ICSI with testicular spermatozoa in obstructive or non-obstructive azoospermia. In total, 193 ICSI cycles were carried out with freshly retrieved testicular spermatozoa; in 139 cases of obstructive and 54 cases of non-obstructive azoospermia. The fertilization rate after ICSI with testicular spermatozoa in non-obstructive azoospermia was significantly lower than in obstructive azoospermia (67.8% versus 74.5%; P = 0.0167). Within the non-obstructive group, the fertilization rate in the group of maturation arrest (47.0%) was significantly lower than in case of Sertoli cell-only (SCO) syndrome (71.2%) or germ cell hypoplasia (79. 5%). Embryo quality on day 2 after ICSI was similar for all groups. Pregnancy rates per transfer between obstructive (36.8%) and non-obstructive groups (36.7%) were similar. In cases of maturation arrest the pregnancy rate per transfer was lowest (20.0%) although not significantly different from SCO syndrome or hypoplasia groups. Embryo implantation rates were not different between the obstructive (19.6%) and non-obstructive groups (25.8%), and were lowest in cases of germ cell hypoplasia (15.8%). This retrospective analysis shows that although fertilization rate after ICSI with testicular spermatozoa in non-obstructive azoospermia is significantly lower than in obstructive azoospermia, pregnancy and embryo implantation rates are similar.