Association between different morphological types and abnormal karyotypes in early pregnancy loss

Comparative cytogenetics of anembryonic pregnancies and missed abortions in human

Miscarriage is an important problem in human reproduction, affecting 10-15 % of clinically recognized pregnancies. The cases of embryonic death can be divided into missed abortion (MA), for which the ultrasound sign of the embryo death is the absence of cardiac activity, and anembryonic pregnancy (AP) without an embryo in the gestational sac. The aim of this study was to compare the frequency of chromosomal abnormalities in extraembryonic tissues detected by conventional cytogenetic analysis of spontaneous abortions depending on the presence or absence of an embryo. This is a retrospective study of 1551 spontaneous abortions analyzed using GTG-banding from 1990 to 2022 (266 cases of AP and 1285 cases of MA). A comparative analysis of the frequency of chromosomal abnormalities and the distribution of karyotype frequencies depending on the presence of an embryo in the gestational sac was carried out. Statistical analysis was performed using a chi-square test with a p <0.05 significance level. The total frequency of chromosomal abnormalities in the study was 53.6 % (832/1551). The proportion of abnormal karyotypes in the AP and MA groups did not differ significantly and amounted to 57.1 % (152/266) and 52.9 % (680/1285) for AP and MA, respectively (p = 0.209). Sex chromosome aneuploidies and triploidies were significantly less common in the AP group than in the MA group (2.3 % (6/266) vs 6.8 % (88/1285), p = 0.005 and 4.9 % (13/266) vs 8.9 % (114/1285), p = 0.031, respectively). Tetraploidies were registered more frequently in AP compared to MA (12.4 % (33/266) vs. 8.2 % (106/1285), p = 0.031). The sex ratio among abortions with a normal karyotype was 0.54 and 0.74 for AP and MA, respectively. Thus, although the frequencies of some types of chromosomal pathology differ between AP and MA, the total frequency of chromosomal abnormalities in AP is not increased compared to MA, which indicates the need to search for the causes of AP at other levels of the genome organization, including microstructural chromosomal rearrangements, monogenic mutations, imprinting disorders, and epigenetic abnormalities.

Study on the correlation between the ultrasound phenotype and copy number variation of abnormal embryo in spontaneous abortion

OBJECTIVE

This study aimed to explore the correlation between the ultrasound phenotype and copy number variation (CNV) of abnormal embryos in spontaneous abortion by investigating the abnormal chromosome copy number of embryos at different developmental stages in early spontaneous abortion.

METHODS

A total of 539 patients who had early spontaneous abortion in our hospital between 2015 and 2019 were divided into seven groups according to the phenotype of abnormal embryonic development during pregnancy, and the embryonic tissues of the patients were subjected by single nucleotide polymorphism (SNP) microarray.

RESULTS

Among 377 cases with abnormal CNV, 295 (78.25%) cases had chromosome trisomy, and 28 (7.43%) cases had a combination of more than two chromosomes. Triploidy, tetraploidy, chromosome microdeletion/duplication, uniparental disomy, and monosomy 45,X were found in 32 (8.48%), five (1.32%), 31 (8.22%), four (1.02%), and eight (2.12%) cases, respectively. Two (0.53%) cases had autosomal chromosome 21 monosomy. Normal karyotype had the highest proportion in the empty sac group; trisomy 16 accounted for the bulk of chromosomes in the normal yolk sac group, complex triploidy occupied the most part in the abnormal yolk sac group, and no remarkable difference in chromosomal abnormality proportion was found between the normal and abnormal yolk sac groups; the most frequent chromosomal anomaly in a group of germ without cardiac activity and germ<5 mm was trisomy 16; triploidy was the most common in the group with 5 mm ≤ germ ≤ 15 mm, whereas the main distribution of chromosome karyotype was normal, followed by trisomy 13 in a group with germ>15 mm.

CONCLUSION

Abnormal embryos with different ultrasound phenotypes in early spontaneous abortion have various CNV types and characteristic distribution. Thus, ultrasound combined with SNP array can provide a basis for the etiological analysis of embryos in spontaneous abortion.

Cytogenetic Analysis of the Products of Conception After Spontaneous Abortion in the First Trimester

In the present study, we retrospectively recruited 340 patients who underwent spontaneous abortions to investigate chromosomal abnormalities of the conception products in the first trimester. We also performed a relevant analysis of clinical factors. Of these patients, 165 had conception products with chromosomal abnormalities, including 135 aneuploidies, 11 triploidies, 10 complex abnormalities, and 9 segmental aneuploidies. The most common abnormal chromosomes were chromosome 16 in the embryo-transfer group and sex chromosomes in the natural-conception group. The most common abnormal chromosomes in all analyzed maternal age groups were sex chromosomes, 16, and 22. The chromosomal abnormality incidence was related to age and number of spontaneous abortions (both p < 0.05), but not to number of pregnancies, deliveries, induced abortions, or methods of conception (all p > 0.05). The rates of abnormality for chromosomes 12, 15, 20, and 22 increased with age, while the rates for chromosomes 6, 7, 13, and X decreased. In all age groups, aneuploidy was by far the most common abnormality; however, the low-incidence distributions of chromosomal abnormalities were entirely different. Overall, chromosomal aneuploidy was the primary cause of pregnancy loss in the first trimester, and low-frequency abnormalities differed across age subgroups. Chromosomal aberrations were found to be related to maternal age and spontaneous abortion, but not all chromosomal abnormalities increased with age.

Association between vaginal microbiota and risk of early pregnancy miscarriage

Approximately 15 % of clinically recognized pregnancies end in miscarriage. To explore the vaginal microbiota profile in women diagnosed with early pregnancy miscarriage (including missed miscarriage [M] or empty-sac miscarriage [E]), the microbial community structure in vaginal fluid was evaluated by Illumina MiSeq sequencing of the 16S rRNA gene V4 region and compared with that in women with normal pregnancy (P). Taxa identified in samples from the P, E, and M groups formed distinct clusters. The M group had the highest bacterial species richness and diversity, with lower Lactobacillus levels and higher Bacteroides, Halomonas, Miscellaneous-Crenarchaeota, Bacillus, Staphylococcus, Escherichia/Shigella, and Acetobacter levels than in the other two groups. The vaginal community-state types differed significantly among the three groups (P = 0.02) but were similar between the P and E groups (P = 0.21). Moreover, we identified an optimal marker set composed of 12 operational taxonomic units based on a random forest model that distinguished the M and P groups, with areas under the receiver-operating characteristic curve of 86.76 % and 93.33 % in the training and test groups, respectively. In conclusion, this study highlights that patients with early pregnancy miscarriage had a significantly different vaginal microbiota profile. Microbial markers analyzed by RT-qPCR may be applied for the etiological diagnosis of miscarriage. Further studies should be performed to elucidate the possible mechanism of special strains affecting miscarriage during early pregnancy.

Coronavirus disease 2019 and first-trimester spontaneous abortion: a case-control study of 225 pregnant patients

Background

The disease caused by the severe acute respiratory syndrome coronavirus 2 was named coronavirus disease 2019 and classified as a global public health emergency. The evidence related to the impact of coronavirus disease 2019 on pregnancy is limited to the second and third trimester of pregnancy, whereas data on the first trimester are scant. Many viral infections can be harmful to the fetus during the first trimester of pregnancy, and whether severe acute respiratory syndrome coronavirus 2 is one of them is still unknown.

Objective

With this study, we evaluated severe acute respiratory syndrome coronavirus 2 infection as a risk factor for early pregnancy loss in the first trimester of pregnancy. Furthermore, coronavirus disease 2019 course in the first trimester was assessed.

Study Design

Between February 22 and May 21, 2020, we conducted a case-control study at S. Anna Hospital, Turin, among pregnant women in their first trimester, paired for last menstruation. The cumulative incidence of coronavirus disease 2019 was compared between women with spontaneous abortion (case group, n=100) and those with ongoing pregnancy (control group, n=125). Current or past infection was determined by the detection of severe acute respiratory syndrome coronavirus 2 from nasopharyngeal swab and severe acute respiratory syndrome coronavirus 2 immunoglobulin G and immunoglobulin M antibodies in a blood sample. Patient demographics, coronavirus disease 2019–related symptoms, and the main risk factors for abortion were collected.

Results

Of 225 women, 23 (10.2%) had a positive test result for coronavirus disease 2019. There was no difference in the cumulative incidence of coronavirus disease 2019 between the cases (11/100, 11%) and the controls (12/125, 9.6%) (P=.73). Logistic regression analysis confirmed that coronavirus disease 2019 was not an independent predictor of early pregnancy loss (odds ratio, 1.28; confidence interval, 0.53–3.08). Coronavirus disease 2019–related symptoms in the first trimester were fever, anosmia, ageusia, cough, arthralgia, and diarrhea; no cases of pneumonia or hospital admission owing to coronavirus disease 2019–related symptoms were recorded. No difference in the incidence of symptoms was noted between the 2 groups.

Conclusion

Severe acute respiratory syndrome coronavirus 2 infection during the first trimester of pregnancy does not seem to predispose to early pregnancy loss; its cumulative incidence did not differ between women with spontaneous abortion and women with ongoing pregnancy. Coronavirus disease 2019 appears to have a favorable maternal course at the beginning of pregnancy, consistent with what has been observed during the second and third trimesters.

Maternal age, history of miscarriage, and embryonic/fetal size are associated with cytogenetic results of spontaneous early miscarriages

PURPOSE

To clarify the associations of the maternal age, history of miscarriage, and embryonic/fetal size at miscarriage with the frequencies and profiles of cytogenetic abnormalities detected in spontaneous early miscarriages.

METHODS

Miscarriages before 12 weeks of gestation, whose karyotypes were evaluated by G-banding between May 1, 2005, and May 31, 2017, were included in this study. The relationships between their karyotypes and clinical findings were assessed using trend or chi-square/Fisher's exact tests and multivariate logistic analyses.

RESULTS

Three hundred of 364 miscarriage specimens (82.4%) had abnormal karyotypes. An older maternal age was significantly associated with the frequency of abnormal karyotype (p_trend < 0.001), particularly autosomal non-viable and viable trisomies (p_trend 0.001 and 0.025, respectively). Women with ≥ 2 previous miscarriages had a significantly lower possibility of miscarriages with abnormal karyotype than women with < 2 previous miscarriages (adjusted odds ratio [aOR], 0.48; 95% confidence interval [95% CI], 0.27-0.85). Although viable trisomy was observed more frequently in proportion to the increase in embryonic/fetal size at miscarriage (p_trend < 0.001), non-viable trisomy was observed more frequently in miscarriages with an embryonic/fetal size < 10 mm (aOR, 2.41; 95% CI, 1.27-4.58), but less frequently in miscarriages with an embryonic/fetal size ≥ 20 mm (aOR, 0.01; 95% CI, 0.00-0.07) than in anembryonic miscarriages.

CONCLUSIONS

The maternal age, history of miscarriage, and embryonic/fetal size at miscarriage may be independently associated with the frequencies or profiles of cytogenetic abnormalities in early miscarriages.

Do specific ultrasonography features identified at the time of early pregnancy loss predict fetal chromosomal abnormality? - A systematic review and meta-analysis

To investigate the association of specific ultrasonography features identified during the diagnosis of early pregnancy loss (EPL) and abnormal karyotype. This was a systematic review and meta-analysis conducted in accordance with PRISMA criteria. We searched PubMed, Cochrane and Ovid MEDLINE from 1977 to Jan 2017 to identify the articles that described EPL with karyotype and ultrasonography features. Risk differences were pooled to estimate the chromosomal abnormality rates in ultrasonography features, including pre-embryonic, enlarged yolk sac (YS), short crown rump length (CRL), small gestational sac (GS), symmetrical arrested growth embryo, or gestational sac with only a YS. Quality assessment of included studies was performed using Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) checklists for Observational Studies (2007 version). Thirteen studies were included in the meta-analysis. Chromosomal abnormality was more likely to occur in embryonic EPL and enlarged YS. On the other hand, short CRL, small GS, symmetrical arrested growth embryo, or gestational sac with only a YS, were not associated with an increased risk of fetal chromosomal abnormality. Ultrasonography features at the time of diagnosis of EPL have limited predictive value of fetal chromosomal abnormality.

A Yolk Sac Larger Than 5 mm Suggests an Abnormal Fetal Karyotype, Whereas an Absent Embryo Indicates a Normal Fetal Karyotype

OBJECTIVES

It is very hard to estimate an abnormal or normal fetal karyotype in miscarriage before surgery. We investigated whether the abnormal fetal karyotype in early miscarriage could be estimated by comprehensive ultrasonographic findings by a multivariate analysis.

METHODS

One hundred fifty-one patients with early miscarriage (<12 weeks' gestation) were selected in our hospital. The clinical characteristics were compared between pregnant women carrying a fetus with an abnormal karyotype and those with a normal one, and the size and configuration of the gestational sac, yolk sac, and embryo at diagnosis of early miscarriage were also evaluated.

RESULTS

The rate of abnormal fetal karyotypes was 66.2 % (100 of 151). A maternal age older than 35 years (odds ratio, 3.2; 95% confidence interval, 1.4-7.4; P = .005), yolk sac larger than 5 mm (odds ratio, 6.2; 95% confidence interval, 2.2-22.7, P < .001), and absent embryo (odds ratio, 0.40; 95% confidence interval, 0.16-0.95; P = .038) were independent markers for predicting an abnormal fetal karyotype by multiple logistic regression analysis.

CONCLUSIONS

At the point of early miscarriage diagnosis, a yolk sac larger than 5 mm suggests an abnormal fetal karyotype, whereas an absent embryo indicates a normal fetal karyotype.

Cardiac Failure in a Trisomy 9 Patient Undergoing Anesthesia: A Case Report

A 27-year-old female with Trisomy 9 mosaicism presented to Children's Hospital Colorado for outpatient dental surgery under general anesthesia. The patient's past medical history was also significant for premature birth, gastroesophageal reflux, scoliosis and kyphosis, obesity, and developmental delay. Per her mother's report, the patient had no cardiac issues. She had undergone multiple previous general anesthetics, some of which documented respiratory complications such as laryngospasm, bronchospasm, and possible aspiration. During this anesthetic, the patient became hypotensive on induction, with sluggish response to intravenous fluids, glycopyrrolate, and ephedrine. Her electrocardiogram demonstrated what appeared to be left bundle branch block at baseline, with possible ST segment changes after induction. Due to her abnormal reaction to the induction and subsequent treatment for hypotension, an echocardiogram was performed. The patient was found to have an ejection fraction of 25%-30%. The anesthetic was uneventful for the remainder of the procedure, and following recovery, the patient was admitted by the heart failure team for further care.

Correlation analysis between ultrasound findings and abnormal karyotypes in the embryos from early pregnancy loss after in vitro fertilization-embryo transfer

PURPOSE

The purpose of the study is to evaluate the correlation between ultrasound findings and abnormal karyotypes in early pregnancy losses (EPLs) after in vitro fertilization-embryo transfer (IVF-ET).

METHODS

This retrospective analysis assessed 2172 cases of EPL after IVF-ET occurring between January 2008 and December 2013. The cases were examined via transvaginal ultrasonography (TVS). Embryonic tissue karyotyping following miscarriage was performed using a comparative genomic hybridization (CGH) analysis with fluorescence in situ hybridization (FISH). The correlations between the ultrasound findings and the karyotypes were evaluated.

RESULTS

Six categories of ultrasound findings were observed: normal ultrasound, empty sac, yolk sac only, small gestational sac, small embryonic pole, and early symmetrical arrested growth. The overall rate of abnormal karyotypes was 44.9 % (976/2172), and the rate of abnormal karyotypes associated with a normal ultrasound, empty sac, yolk sac only, small gestational sac, small embryonic pole, and early symmetrical arrested growth was 49.5 % (218/440), 28.1 % (138/491), 43.4 % (197/454), 50.0 % (43/86), 49.8 % (155/311), and 57.7 % (225/390), respectively. Compared with the other groups, the prevalence of chromosomal abnormalities was significantly higher in the early symmetrical arrested growth group but was markedly lower in the empty sac group in all cases and when cases of 46,XX were excluded (p < 0.05). Trisomy 16 was the most common chromosomal abnormality in the yolk sac only, small embryonic pole and early symmetrical arrested growth groups. In the empty sac, small gestational sac and normal ultrasound groups, monosomy X was the most frequent abnormality.

CONCLUSIONS

Chromosomal anomalies may be associated with specific types of ultrasound findings in EPLs after IVF-ET.

Correlation between chromosomal distribution and embryonic findings on ultrasound in early pregnancy loss after IVF-embryo transfer

STUDY QUESTION

Do early pregnancy losses (EPLs) with and without embryos differ in chromosomal distributions?

SUMMARY ANSWER

The chromosomal abnormality rate is significantly higher in miscarriages with embryos than without after in vitro fertilization (IVF)-embryo transfer.

WHAT IS KNOWN ALREADY

Chromosomal abnormalities are the main causes of EPLs, the rate of which is up to 24-30% in the IVF population. Little research has been conducted on the correlations between the chromosomal distributions of EPL and the existence of an embryo or with the postmortem embryonic pole length, and the existing results have been inconsistent.

STUDY DESIGN, SIZE, DURATION

The data of 2172 women who underwent dilation and curettage (D&C) from January 2008 to December 2013 for missed abortion were analyzed retrospectively. The existence of an embryonic pole and the length of the postmortem embryonic pole of the EPL were evaluated by transvaginal sonography (TVS). Ultrasound findings were compared with karyotype results.

PARTICIPANTS/MATERIALS, SETTING, METHOD

This analysis included 2172 infertility patients who had singleton pregnancies and experienced EPLs after IVF-embryo transfer. The EPLs were divided into embryonic and anembryonic groups based on TVS diagnosis. The crown-rump length of the fetal pole (observed once) was measured twice for each fetus after confirmation of fetal death, subject to the final measurement before D&C. The karyotype analysis was performed using comparative genomic hybridization (CGH) plus fluorescence in situ hybridization technology.

MAIN RESULTS AND THE ROLE OF CHANCE

The chromosomal abnormality rate was significantly higher in male miscarriages with an embryo than in those without an embryo (54.14% versus 37.50%, P ≤ 0.001). In the anembryonic group, the abnormal karyotype rate was significantly higher in the yolk sac only than that in the empty sac group (46.11% versus 29.77%, P = 0.001); in the embryonic group, the abnormal karyotype rate in miscarriages with postmortem embryonic pole length >20 mm was significantly lower than that in miscarriages with pole length <10 mm (P = 0.006) and 10-20 mm (P = 0.036). There were significant differences in abnormal karyotype rates among miscarriages of different developmental stages (P ≤ 0.001). The cases with embryonic stages had the highest risk (54.89%) of an abnormal karyotype and those with fetal stages had the lowest risk (18.18%). There were significant differences in the length of postmortem embryonic poles among groups with different karyotypes (P ≤ 0.001). In addition, trisomy 21, monosomy X and triploidy had the longest lengths of postmortem embryonic poles (16, 15.3 and 11.6 mm, respectively).

LIMITATIONS, REASONS FOR CAUTION

Although the efficacy of a non-parametric test is less than that of a parametric test, non-parametric testing was used to compare the embryonic pole lengths in this study, owing to the non-normal distribution and non-homogeneous variances caused by limited cases of some rare chromosomal abnormalities. Another limitation was that CGH was unable to detect mosaicism. Furthermore, the results were not compared with a non-IVF population. Finally, maternal cell contamination is a major problem in studying miscarriage tissue, even using molecular techniques.

WIDER IMPLICATIONS OF THE FINDINGS

Although TVS findings clearly cannot replace karyotype information, our results are important because they call attention to the fact that EPLs that occur after implantation but prior to embryo formation frequently have normal karyotypes. This finding might direct future research towards studies of DNA sequences, or of epigenetic correlations with pregnancy failure.

STUDY FUNDING/COMPETING INTERESTS

This study was funded by the Scientific Research Foundation of Reproductive and Genetic Hospital of Citic-Xiangya. The authors have declared that no conflicts of interest exist.

TRIAL REGISTRATION NUMBER

N/A.

Two-year outcome after recurrent first trimester miscarriages: prognostic value of the past obstetric history

PURPOSE

Recurrent miscarriage (RM) is a stressful condition which gives rise to extensive diagnostic evaluation and is seen as a potentially curable maternal disease. Nevertheless, epidemiological data have shown that outcome is related to fertility. In addition to maternal age and number of preceding miscarriages, further markers derived from the past history may support counselling.

METHODS

Observational trial comprising 228 couples who were referred between 1996 and 2003 for immunological evaluation at maternal ages 20-39 years after three or more spontaneously conceived primary first trimester miscarriages. They were interviewed in 2005, ongoing pregnancies were followed up until birth in 2006. Past obstetric history was correlated with 2 year cumulative pregnancy and delivery rates (CPR, CDR).

RESULTS

CPR and CDR were 206/228 (90.4 %) and 174/228 (76.4 %). Duration of infertility was associated with lower CPR (up to 3/>3 years, p < 0.01), whereas age and number of preceding losses inversely correlated with CDR (<35 years/35-39 years, p < 0.002; 3/>3 miscarriages, p < 0.002). Detection of an embryonic heart beat in 2-3 of the first three miscarriages resulted in favourable outcome (CPR: p < 0.02, CDR: p < 0.002). Prognosis was excellent in younger fertile women after three miscarriages where vital signs had been detected; under less favourable conditions not only risks for further miscarriage, but also for secondary infertility were elevated.

CONCLUSION

Secondary infertility is a feature of RM. Embryonic vital signs in preceding pregnancies are prognostic markers and should be regarded as a strong confounding factor in trials on therapeutic interventions. Prevention may be more appropriate than treatment.

Differentiation of genetic abnormalities in early pregnancy loss

OBJECTIVE

To characterize the types of genetic abnormalities and their prevalence in early pregnancy loss at different developmental stages. We hypothesized that the prevalence of genetic abnormalities in pregnancy loss would differ across developmental stages.

METHODS

Women with a pregnancy loss at < 20 weeks' gestation (n = 86) were enrolled at the time of diagnosis. Maternal tissue without a fetal component was found in 13 samples. Chromosomal microarray analysis (CMA) was performed on 74 samples (including two samples from a twin pregnancy); 15 were pre-embryonic (no visible embryo on ultrasound examination), 31 were embryonic (embryo; 6 + 0 to 9 + 6 weeks' gestation) and 28 were fetal (fetus; 10 + 0 to 19 + 6 weeks' gestation) losses. The twin pregnancy was found to be monochorionic diamniotic and was subsequently treated as a single sample in our analysis. Nine samples that underwent CMA were excluded from analysis because of 100% maternal-cell contamination.

RESULTS

The overall prevalence of genetic abnormalities differed across developmental stages (9.1% pre-embryonic, 69.2% embryonic and 33.3% fetal; P < 0.01). This difference persisted when comparing pre-embryonic with embryonic samples (P < 0.01) and embryonic with fetal samples (P = 0.02) but not pre-embryonic with fetal samples (P = 0.12). Additionally, the prevalence of aneuploidy differed significantly across developmental stages (0.0% in pre-embryonic samples vs 65.4% in embryonic samples vs 25.9% in fetal samples, P < 0.001). Abnormalities were most common in embryonic cases, followed by fetal and then pre-embryonic. Maternal cell contamination (MCC) was noted in 47.4% of 46,XX cases assessed.

CONCLUSIONS

Genetic abnormalities detected by CMA are more likely to occur in the embryonic period than in pre-embryonic or fetal stages. MCC is common in early pregnancy loss and should be excluded when results demonstrate a 46,XX karyotype.

Cytogenetic and morphological analysis of early products of conception following hystero-embryoscopy from couples with recurrent pregnancy loss

OBJECTIVE

Our knowledge about miscarriages mainly concerns pregnancies of at least 8 weeks' gestation. Information about the morphology and the genetic determinants of early aborted embryos remains limited. In addition, it is known that aneuploidies account for less than half of recurrent spontaneous abortions. We hypothesized that (recurrent) early pregnancy losses might have other genetic causes.

METHOD

Products of conception from 51 couples with at least one previous miscarriage were collected by hystero-embryoscopy. The extracted DNA was analyzed by low resolution array comparative genomic hybridization and high resolution single nucleotide polymorphism arrays to detect aneuploidies, polyploidies, submicroscopic copy number variants or copy neutral loss of heterozygosity.

RESULTS

Chromosomal aberrations were identified in 65.6% (21/32) of miscarriages and in 89% (8/9) of anembryonic cases. Interestingly, 4/11 chromosomally euploid embryos contained regions of loss of heterozygosity >5 Mb, suggesting the miscarriages might be due to an underlying lethal recessive disease.

CONCLUSION

Hystero-embryoscopic biopsy followed by array comparative genomic hybridization is a valuable diagnostic tool for early and recurrent miscarriages. Genome-wide high resolution single nucleotide polymorphism microarray analysis of a larger group of miscarriages could provide more insight into the genetic causes of recurrent spontaneous abortion.

Is the yolk sac a new marker for chromosomal abnormalities in early pregnancy?

INTRODUCTION

Abnormal yolk sac size is associated with fetal miscarriage. This is a case report of two pregnancies with abnormal yolk sacs.

MATERIALS AND METHODS

In one case, a twofold sac was found; in the other case, the yolk sac was not of spherical form.

CONCLUSION

Currently available publications demonstrate a correlation between abnormal yolk sac size and miscarriage. However, in both cases a trisomy was confirmed. It should therefore be discussed whether form and size of the yolk sac could be a marker for chromosomal abnormalities of the fetus.