Recurrent pregnancy losses and parental chromosome abnormalities: a review

Summary. A compilation of the cytogenetic results taken from 79 published surveys of couples with two or more pregnancy losses (comprising 8208 women and 7834 men) showed an overall prevalence of major chromosome abnormalities of 2.9%. This is five to six times higher than that of the general adult population. In every group of chromosome abnormalities in the parents a predominance of female to male affected was noted (2:1). Approximately 50% of all chromosome abnormalities detected were balanced reciprocal translocations, 24% were Robertsonian translocations, 12% were sex chromosomal mosaicisms in females, and the rest consisted of inversions and other sporadic abnormalities. Parents with two or more idiopathic pregnancy losses should be karyotyped to aid in management and counselling. When a translocation or other abnormality (e.g. X chromosomal mosaicism) predisposing to an abnormal zygote is found, prenatal diagnosis is indicated in future pregnancies. Even when parental karyotypes are normal, prenatal diagnosis should be considered in subsequent pregnancies of parents with two or more pregnancy losses because of the high incidence of chromosome abnormalities in spontaneous abortions. For the same reason, if a single previous pregnancy loss is known to have been chromosomally aneuploid, parental karyotypes may have to be examined (depending upon the finding in the pregnancy loss), and prenatal diagnosis should also be considered in subsequent pregnancies.     

3405例产前诊断的指证及其结果评价

目的:分析产前诊断指证与胎儿染色体检测结果的关系。方法:3405例有产前诊断指证的孕妇,进行羊膜腔穿刺或脐静脉穿刺术,取羊水细胞或脐血细胞培养,作胎儿染色体核型分析。结果:3405例孕妇共检出胎儿染色体异常88例,染色体异常率为2.6%,显著高于一般人群的异常率(P<0.01)。其中夫妇一方为染色体平衡易位携带者组的胎儿染色体异常率达25.9%(7/27),产前胎儿超声异常标记组、孕母血清唐氏筛查阳性组和高龄孕妇组的异常率分别为6.2%(49/778)、1.7%(22/1283)和1.1%(7/664)。18-或21-三体儿妊娠史组、体外受精组、本次妊娠有先兆流产史组和孕期不良因素接触组,均未检出胎儿染色体异常。结论:出现胎儿染色体异常率最高的指证,依次为夫妇一方染色体平衡易位携带者、产前超声发现胎儿异常标记、孕母血清唐氏筛查阳性和高龄孕妇。有针对性地进行产前诊断,可有效地控制和减少出生缺陷的发生。     

Chromosome abnormalities detected in chorionic villus biopsies of failing pregnancies in a subfertile population.

OBJECTIVE--To determine the range and prevalence of chromosomal abnormalities occurring in failing pregnancies in subfertile women. DESIGN--Prospective biochemical and ultrasound monitoring of all pregnancies conceived between 1988 and 1990 in a subfertile population. SETTING--A single-centre specialist fertility clinic in Perth, Western Australia. SUBJECTS--Tissue from 50 early pregnancy losses was successfully cultured for chromosomal analysis from 46 pregnancies comprising 29 anembryonic pregnancies, 9 miscarriages and 8 ectopic pregnancies. MAIN OUTCOME MEASURES--Impending pregnancy loss was identified at an early stage. Chromosomal analysis was performed on chorionic villi obtained before the diagnosis became clinically evident. RESULTS--Significant chromosomal abnormalities were identified in 54% (14/26) of early pregnancy losses where gamete manipulation was involved and 45% (9/20) of those following spontaneous conception. The most common abnormalities were trisomies (12 pregnancies, mainly trisomy 16), triploidies (3 pregnancies) and monosomy X (3 pregnancies). An excess of female fetuses was noted with only 24% of conceptuses (11/46) bearing a Y chromosome. CONCLUSIONS--The data indicate a similar rate of chromosomal abnormalities underlying pregnancy losses at earlier stages of pregnancy and after infertility treatments as that reported from the general population. Gamete manipulation does not appear to confer a higher rate of chromosomal abnormalities in ensuing pregnancies.     

Factors influencing parental decision making in prenatal diagnosis of sex chromosome aneuploidy

OBJECTIVE: To evaluate factors influencing parental decisions toward continuing or terminating a pregnancy with prenatal diagnosis of sex chromosome aneuploidy. METHODS: We reviewed the records of patients with fetuses with sex chromosome aneuploidy between 1990 and 2001. A questionnaire survey of women who chose to terminate such pregnancies was designed to examine aspects of their decision-making process. RESULTS: Forty-nine of 89 pregnancies with sex chromosome aneuploidy were terminated (termination rate 0.55; 95% confidence interval 0.45-0.65). Pregnancies with abnormal ultrasound findings (14/16, 87%), with 45,X or 47,XXY karyotypes (26/36, 72%), and with nonmosaic karyotypes (30/48, 63%) were terminated significantly more often than pregnancies with normal ultrasound findings (35/73, 48%; P <.01), with 47,XXX or 47,XYY karyotypes (4/12, 33%; P <.05), and with mosaic karyotypes (5/25, 20%; P =.01). There was a trend (P =.136) toward a lower rate of termination from 67% to 36% across time, with a significant decrease from 67% to 7% in pregnancies with 47,XXX; 47,XYY; and mosaic karyotypes (P <.01), and no change in cases with 45,X and 47,XXY karyotypes (67% compared with 69%; P = 1.0). Abnormal sexual development and infertility were the greatest parental concerns related to termination. CONCLUSION: Fear of having a child with abnormal sexual development or infertility remains the major determinant of parental decision toward terminating pregnancy, resulting in consistently high termination rates across time in pregnancies with 45,X and 47,XXY karyotypes. In cases with 47,XXX; 47,XYY; and mosaic karyotypes, the declining termination rate across time is a consequence of recent studies reporting normal sexual development and fertility.     

The outcome of pregnancy and prenatal chromosomal diagnosis of fetuses in couples including a translocation carrier.

In order to evaluate the relation between chromosomal translocation and the outcome of pregnancy, 50 couples were examined. Subjects consisted of 35 couples that included a reciprocal translocation carrier; 13 included a Robertsonian translocation carrier and 2 included a carrier of a mosaic reciprocal translocation. The reasons for performing chromosomal examinations were mainly infertility and abnormality of neonates. The rates of miscarriages and neonatal abnormalities in prior pregnancies were significantly higher than the birth rate of morphologically normal newborns. The presence of a translocation is closely related to reproductive failure because of the chromosomal imbalance. However, prenatal chromosomal examination after the 15th gestational week in subsequent pregnancies revealed that almost half of the fetuses showed normal karyotypes and only 12.8 per cent of the fetuses showed a chromosomal imbalance. Many chromosomally imbalanced fetuses are spontaneously aborted before amniocentesis. The risk of chromosomal imbalance is relatively low in prenatal diagnosis, but partial trisomies of small rearrangements tend to be preserved.     

Pregnancy outcome and prognosis in fetuses with increased first-trimester nuchal translucency.

OBJECTIVE: One of the concerns of prenatal diagnosis is to find sensitive markers to screen for chromosome abnormalities, such as serum assays or nuchal translucency (NT). This study reports our experience with NT measurement during the first trimester of pregnancy. MATERIALS: The study was performed prospectively on 252 fetuses with either NT > or =3 mm or cystic hygroma. RESULTS: We observed 50 abnormal karyotypes, i.e. 19.8%. The incidence of chromosome abnormalities increased with increasing maternal age and increasing NT thickness. For the 202 fetuses with normal karyotypes, outcome was unfavourable in 32 cases: 23 elective terminations of pregnancy, 8 spontaneous abortions and 1 neonatal death. Outcome was favourable in 141 cases. Twenty-nine pregnancies were lost to follow-up. CONCLUSION: Measurement of NT at 12 weeks' gestation seems to be a good marker for chromosome abnormalities. When the karyotype is normal, the pregnancy outcome remains correlated with the degree of NT thickness. The finding of NT >3 mm between 10 and 14 weeks' gestation dictates rigorous ultrasound monitoring and caution when predicting pregnancy outcome.     

2414例胎儿羊水细胞的体外培养及染色体核型分析

目的:探讨羊水细胞染色体分析在产前诊断中的应用价值。方法:无菌条件下,经B超介导,对2 414名孕16~25周的孕妇行羊膜腔穿刺术,每例抽取羊水20 ml,经体外培养后进行G显带,显微镜下做核型分析,并了解异常核型的相应高危因素分布情况。结果:共收集到2 414例羊水标本,2 407例培养成功,成功率为99.7%。核型异常124例,异常率为5.1%。其中,染色体数目异常46例,三体综合征38例,占数目异常的82.6%(38/46);结构异常56例,随机的平衡易位、倒位及罗氏易位共47例,占结构异常的83.9%(47/56);22例嵌合体均进行了脐带血核型分析,结果核型均正常。将孕妇按行穿刺的首要指征分为7组,唐氏综合征筛查高危组和高龄组的受检人数分别占48.3%和36.6%,显著多于其他组(P<0.05);B超检查示胎儿异常组、颈后透明层(nuchaltranslucency,NT)增厚组及夫妇一方为染色体异常携带者组的核型异常检出率分别为25.5%、19.0%及17.2%,与其它组比较差异显著(P<0.05)。结论:改进的羊水细胞体外培养方法对核型分析更具实用性。羊水染色体核型分析是安全、有效的诊断胎儿染色体病的方法,在产前诊断中占有重要地位。     

Late terminations of pregnancy following second trimester amniocentesis

We sought information from 34 chromosome laboratories in Britain about the frequency during 1982 of late amniocentesis, late reports of prenatal diagnosis results and late resultant terminations of pregnancy. Thirty-one laboratories provided data on a total of 20 840 pregnancies. Gestational age at report was recorded in 14 795 and 510 subsequent terminations of pregnancy were recorded. The data were subdivided into three categories according to the primary indication for amniocentesis: (i) the detection of chromosomal abnormalities, (ii) risk of neural-tube defect, (iii) 'other' reasons. Overall 4.0% of diagnostic amniocenteses were performed at greater than or equal to 21 weeks, 12.7% of reports were made at greater than or equal to 22 weeks gestation, and 13.1% of terminations were performed at greater than or equal to 22 weeks. Late amniocentesis (greater than or equal to 21 weeks) occurred nearly five times more often when the primary indication was the detection of neural tube defects than when it was the detection of chromosomal abnormalities. Approximately two-thirds of 'late' terminations were performed after amniocentesis at greater than or equal to 19 weeks gestation. A total of 3896 (26.3%) of women undergoing prenatal diagnosis had to wait until greater than or equal to 21 weeks gestation before a report was available.     

Relationship between maternal age and aneuploidy in in vitro fertilization pregnancy loss

OBJECTIVE: To determine the fetal loss rate after documented fetal cardiac activity (7-week sonogram) and to evaluate the chromosomal makeup of these losses in IVF pregnancies. DESIGN: Retrospective analysis. SETTING: University-based IVF center. PATIENT(S): Two thousand fourteen consecutive IVF pregnancies with documented fetal cardiac activity. MAIN OUTCOME MEASURE(S): Miscarriage rates and karyotypes of pregnancy losses were analyzed. RESULT(S): The overall pregnancy loss rate after demonstrated fetal cardiac activity was 11.6% (233/2014). A highly significant increase in fetal loss with advancing maternal age was observed (<30 years = 5.3% vs. 31-34 years = 7.6% vs. 35-39 years = 12.8% vs. > or =40 years = 22.2%). Patients with a multiple gestation were more likely to deliver a live infant, compared with those with a singleton detected at a 7-week sonogram. Of the 233 losses in the study period, cytogenetic analyses were obtained for 74 (31.8%). Three specimens were nondiagnostic. Fifty-two patients had abnormal karyotypes (71.2% [52/71]). Eighty-two percent of the pregnancy losses in women aged > or =40 years were associated with chromosomally abnormal fetuses, compared with 65% of the losses in women aged <40 years (odds ratio, 3.35; 95% confidence interval, 0.96-11.97). CONCLUSION(S): Pregnancy loss after documentation of fetal cardiac activity is >10%. This loss is significantly increased with advancing maternal age. The major underlying cause of these losses seems to be chromosomal aneuploidy.     

A pregnancy with discordant fetal and placental chromosome 18 aneuploidies revealed by invasive and noninvasive prenatal diagnosis

This study investigated a pregnancy where the fetus was diagnosed with monosomy 18p by invasive amniocentesis and karyotyping. Additional noninvasive prenatal diagnosis, which detects fetal chromosome abnormalities in the circulating cell-free plasma DNA originating from the placenta revealed a related 18p monosomy/18q trisomy, suggesting confined placental mosaicism. Based on recent observations of chromosomal instability in the early preimplantation embryo, this study speculates on the possible embryonic origin(s) of these related but discordant chromosome 18 aneuploidies in the placental and fetal tissues. The findings highlight the potential for both false-positive and -negative noninvasive prenatal diagnosis results in pregnancies where there is either confined placental mosaicism or placental mosaicism.The study investigated a pregnancy involving a fetus with a chromosome disease syndrome called monosomy 18p where part of the short arm of chromosome 18 was missing in the fetal tissues. Using non-invasive prenatal diagnosis which detects fetal chromosome abnormalities in the circulating cell free plasma DNA originating from the placenta, we also detected monosomy 18p as well a related chromosome 18 abnormality involving duplication of the long arm of chromosome 18. This suggested confined placental mosaicism where the constitution of the chromosomes are different between fetal and placental tissues. We speculated that these related chromosome 18 abnormalities arose during preimplantation embryo development, leading to the formation of different chromosome abnormalities observed in the placental and fetal tissues of this pregnancy. Our findings highlight the potential for both false positive and negative non-invasive prenatal diagnosis test results in pregnancies where there is confined placental mosaicism.     

Parental decisions following prenatal diagnosis of sex chromosome aneuploidy: a trend over time

Research over the last 20 years has considerably changed the understanding of the natural history and prognosis for individuals with a diagnosis of sex chromosome aneuploidy (SCA). A cross-sectional retrospective analysis of factors influencing parental decisions following a prenatal diagnosis of SCA during the time period of 1971-97 was performed. The records of 169 fetuses with a prenatal karyotype of 45,X, 47,XXX, 47,XXY, and 47,XYY were reviewed. Mosaic karyotypes for SCA were also included. Information reviewed involved: parental decision, the type of SCA, the presence or absence of mosaicism, the presence or absence of a fetal anomaly diagnosed by ultrasound examination, indication for prenatal diagnosis, prenatal procedure performed, parental age, marital status, previous pregnancy history, family history, ethnicity, religion, education, and profession. A significant correlation was found between the decision to continue a pregnancy and the type of SCA and the presence of fetal abnormalities on ultrasound examination. In addition, this study examined differences in parental decisions over time for the years in question. A statistically significant trend was observed with a higher rate of pregnancy continuation in the more recent years.     

1981例高龄孕妇的产前细胞遗传学诊断

目的通过高龄孕妇产前胎儿染色体核型结果分析,探讨高龄妊娠胎儿染色体异常的风险。方法通过对高龄孕妇羊水穿刺1807例和脐带血穿刺174例染色体核型分析,探讨高龄妊娠胎儿染色体异常的比率,对比35～37岁、38～40岁、≥41岁三组孕妇胎儿染色体异常发生率,分析不同高龄组胎儿染色体异常的风险比率。结果 1981例高龄孕妇共发现胎儿染色体核型异常61例,染色体异常发生率为3.08%,且随孕妇年龄增长,胎儿染色体异常的发生率显著增高(P0.01)。结论随着孕妇年龄增长,胎儿染色体异常风险逐渐增高,高龄孕妇有必要行产前诊断。     

9例多胎妊娠合并胎儿染色体异常患者的产前诊断和治疗

目的探讨多胎妊娠合并胎儿染色体异常的产前诊断方法及选择性减胎术定位方法。 方法选取2012年1月至2013年12月就诊于广州医科大学附属第三医院9例多胎妊娠合并胎儿染色体异常患者的临床资料,采用回顾性研究方法对其产前诊断方法、染色体异常情况、选择性减胎术的方法及妊娠结局进行分析。 结果9例患者中3例为三胎妊娠,6例为双胎妊娠。(1)产前诊断：①超声检查：9例患者早孕期行超声检查,均提示存在胎儿颈项透明层(nuchal translucency, NT)增厚,孕中期超声检查提示有6例患者存在胎儿结构异常,包括颈部囊肿、心脏异常、外生殖器畸形、足内翻、全身水肿等;②染色体检查：5例胎儿21-三体综合征,1例Turner综合征,1例染色体微缺失,1例染色体重复,1例双胎染色体异常。(2)治疗及妊娠结局：9例患者中7例患者行选择性减胎术治疗,1例流产,3例早产(新生儿均存在并发症),3例足月分娩(新生儿均未见异常);2例患者拒绝减胎,1例于孕中期自然流产,1例于孕35^＋周剖宫产分娩(1胎儿为21-三体综合征,另一胎儿为健康儿)。 结论多胎妊娠应注重早孕期染色体筛查,确诊宫内胎儿染色体异常的患者可在超声引导下行选择性减胎术治疗。     

Screening and diagnosis of chromosomal abnormalities in twin pregnancy

Twin pregnancies are at an increased risk of adverse pregnancy and perinatal outcome as compared to singleton gestations, mainly as the consequence of the higher rate of preterm birth, chromosomal as well as structural anomalies, placental abnormalities, and complications unique to monochorionic placentation.Screening for chromosomal anomalies poses diagnostic and management challenges when applied to twin pregnancies. The recent implementation of cell-free fetal DNA (cffDNA) in clinical practice raises the questions whether a more accurate test should be offered to twin pregnancies in view of the higher false positive rate of traditional screening and the higher risk of fetal loss following amniocentesis or chorionic villus sampling (CVS) in multiple gestations. Finally, twin pregnancies require a tailored approach for aneuploidy screening, such as nuchal translucency (NT) or crown rump length discordance, discordant fetal anomalies, or monoamniotic gestations.The present review aims to provide an up-to-date critical appraisal of screening and prenatal diagnosis of chromosomal abnormalities in twin pregnancies.     

Fetal chromosomal analysis of pregnancies following intracytoplasmic sperm injection with amniotic tissue culture

OBJECTIVES: The objective of this study was to determine the incidence of chromosomal anomalies in a complete cohort of ICSI pregnancies. METHODS: From January 1996 to December 2000, 1500 consecutive patients who had become pregnant after Intracytoplasmic Sperm Injection (ICSI) were given prenatal genetic counseling and 98 of them (6.5%) who accepted amniocentesis were studied. Amniocentesis was performed between 14 and 20th weeks of their pregnancy. Amniotic tissue cultures were processed according to Hoehn et al. A minimum of 20 metaphases were examined on each preparation. Both parents were also evaluated with peripheral blood karyotyping. RESULTS: Amniocentesis and karyotyping was performed to evaluate the 142 fetuses from 98 ICSI pregnancies. Karyotypes from peripheral leucocytes of the parents were also evaluated. Chromosomal anomalies were detected from 6 out of the 142 (4.2%) fetuses. The anomalies were as follows, '46,XX/69,XXX/92,XXXX', '46,XY/69,XXY/92,XXYY', '47,XY + 21', '46,XY/47,XY + 7', '47,XXY', and '45,X0'. All except one pregnancy were terminated with the consent of the couples. Fetal tissue cultures were also studied after the termination of the pregnancy in order to confirm prenatal diagnosis. We did not detect abnormal karyotype from the parents of these fetuses. CONCLUSIONS: The ratio of chromosomal abnormalities seems to be slightly increased in ICSI pregnancies. Paternal factors due to morphologically abnormal spermatozoa, maternal factors due to increased mother age and more frequently, de novo occurring sex chromosomal abnormalities may be responsible for this outcome.     

羊水细胞染色体产前诊断3495例结果分析

目的 探讨各种细胞遗传学产前诊断指征与胎儿染色体异常的关系。方法 2011年1月至2013年4月于重庆医科大学附属第一医院妇产科在知情同意的前提下,由超声引导对3495例孕中期高危孕妇（孕16~21+6周）行羊膜腔穿刺术,抽取适量羊水进行细胞培养及染色体核型分析。比较不同产前诊断指征与胎儿染色体异常核型检出率的关系。 结果 羊水培养成功3494例,成功率99.97%。检出异常核型120例,异常率为3.43%（120/3494）,其中染色体数目异常70例,结构异常31例,其他异常19例。各种产前诊断指征中,单纯高龄（分娩时孕妇年龄≥35岁）1498例,检出异常核型47例,异常检出率为3.14%;母血清学筛查高风险1560例,异常核型38例,检出率2.44%;无创产前DNA检测高风险38例,异常核型30例,检出率78.95%,后者检出率分别与前两者相比差异有统计学意义（P<0.05)。结论 掌握好各种产前诊断指征,对高危孕妇进行羊膜腔穿刺及染色体核型分析可有效提高胎儿染色体病的检出率,减少出生缺陷的发生。     

Long-term effect of prospective detection of high genetic risk on couples' reproductive life: data for thalassaemia

Prospective risk detection with availability of prenatal diagnosis is the best service currently available for couples at high genetic risk Here we describe the long term effect of this service on the reproductive life of 102 couples at risk of thalassaemia, whose risk was detected prospectively by carrier screening, who made use of prenatal diagnosis, and where the woman is now over 40. Overall outcome for couples is described in terms of number of favourable versus unfavourable pregnancy outcomes. (A favourable pregnancy outcome = unaffected livebirth, or affected livebirth resulting from informed parental choice.) The 102 couples had a total of 356 pregnancies, including 302 viable pregnancies, and 88% achieved a family unburdened by thalassaemia. 68% of viable pregnancies had a favourable outcome, but only 43% of couples had only favourable outcomes, and 26% lost two or more viable wanted pregnancies. When early losses are included 58% of pregnancies had a favourable outcome, but only 30% of couples had only favourable outcomes, and 41% lost two or more pregnancies. Even with the best available service, at risk couples remain victims of chance, and a significant minority experience great difficulty in obtaining even one healthy child. Research is needed on approaches that may allow couples better control of reproductive outcomes.     

Etiology of recurrent pregnancy losses and outcome of subsequent pregnancies

Prospective evaluation of 155 couples with two or more consecutive pregnancy losses disclosed uterine morphologic abnormalities in 27%, chromosomal abnormalities in 21 individuals (7.7%, or 15.4% of the couples), and at least one abnormal diagnostic test suggestive of a cause for recurrent pregnancy losses in 106 (68%). A positive test for antinuclear antibody was found in 7.5% of the women, whereas the expected rate in a population of this age is less than 2%. Cervical cultures for Ureaplasma urealyticum (T-strain mycoplasma) were positive in 48% of the women, and 28% of these women had a genetic or uterine abnormality to explain their pregnancy losses. Thyroid function profiles and cervical cultures for Mycoplasma hominis provided no significant information in the evaluation in these couples. With the exception of women with a positive antinuclear antibody, the overall prognosis for later pregnancies was quite good whether the diagnostic evaluation of the couple was normal (77% subsequent live births) or abnormal (71% subsequent live births). The significance of the positive antinuclear antibody in these women is unclear, but further studies and long-term evaluation are necessary to determine the relationship between recurrent pregnancy losses and later development of collagen-vascular diseases.     

Study of 156 cases of polyhydramnios and congenital malformations in a series of 118,265 consecutive births

Polyhydramnios associated with congenital anomalies was studied over nine years in 118,265 consecutive pregnancies. The prevalence of this association was 1.32% (156 cases). A case-control study allowed the examination of genetic and environmental factors for the origin of polyhydramnios associated with congenital malformations. Diagnosis of polyhydramnios associated with congenital malformations was performed prenatally in 41% of the cases; 16% of the infants were stillborn. Fifty-five percent of the cases had more than one malformation, 13.4% of them had a chromosomal aberration, and 32% had multiple malformations that do not constitute a syndrome. There was an increase of consanguinity in the parents of our patients. The incidence of polyhydramnios and congenital anomalies in first-degree relatives was 3.8%, and first-degree relatives had more malformations than the controls had (8.3% vs 3.2%). Our study demonstrated the low capacity of a general prenatal screening program because the diagnosis of malformations associated with polyhydramnios was made in only 41% of the cases and only six of 21 chromosomal abnormalities were diagnosed prenatally. We recommend the use of fetal chromosome analysis and careful ultrasonographic examination in every pregnancy complicated by polyhydramnios.     

Karyotype evaluation of repeated abortions in primary and secondary recurrent pregnancy loss

To study the contribution of embryo chromosomal abnormalities in primary and secondary recurrent pregnancy loss (RPL) and to analyze the recurrence of chromosomal constitution in miscarriages from the same couple. Retrospective study of abortion karyotypes in RPL families based on the mother’s primary or secondary RPL status (563 embryo specimens, 335 samples from primary, and 228 samples from secondary RPL). RPL was defined as two or more consecutive miscarriages. One hundred eight cases of recurrent embryo/fetal loss in 51 families were analyzed to assess the probability of having the same karyotype pattern (recurrent normal or recurrent abnormal) in both previous and subsequent pregnancy loss. The karyotypes of abortions were established using standard cytogenetic analysis, as well as interphase fluorescence in situ hybridization (FISH) and comparative genomic hybridization (CGH). The frequency of aberrations was 43.9% in abortions from primary RPL versus 52.6% in secondary RPL (p = 0.041). Women 35 years of age or older were the main contributors to this difference. The odds ratio of a subsequent abortion having the same karyotype pattern (normal or abnormal) as the previous one was 6.98 (p = 0.0013). The frequency of abnormalities is higher in abortions from the secondary RPL versus primary RPL group, and this difference is due to the relative deficiency of miscarriages with abnormal karyotypes in older women with primary RPL. The probability of having the same karyotype pattern (recurrent normal or recurrent abnormal) in the previous and subsequent abortion is increased significantly compared with chance.