Added value of chromosomal microarray analysis over conventional karyotyping in stillbirth work-up: systematic review and meta-analysis

The chromosomal characteristics of spontaneous abortion and its potential associated copy number variants and genes

PURPOSE

This study aimed to investigate the correlation between chromosomal abnormalities in spontaneous abortion with clinical features and seek copy number variations (CNVs) and genes that might be connected to spontaneous abortion.

METHODS

Over 7 years, we used CNV-seq and STR analysis to study POCs, comparing chromosomal abnormalities with clinical features and identifying critical CNVs and genes associated with spontaneous abortion.

RESULTS

Total chromosomal variants in the POCs were identified in 66.8% (2169/3247) of all cases, which included 45.2% (1467/3247) numerical abnormalities and 21.6% (702/3247) copy number variants (CNVs). Chromosome number abnormalities, especially aneuploidy abnormalities, were more pronounced in the group of mothers aged ≥ 35 years, the early miscarriage group, and the chorionic villi group. We further analyzed 212 pathogenic and likely pathogenic CNVs in 146 POCs as well as identified 8 statistically significant SORs through comparison with both a healthy population and a group of non-spontaneously aborted fetuses. Our analysis suggests that these CNVs may play a crucial role in spontaneous abortion. Furthermore, by utilizing the RVIS score and MGI database, we identified 86 genes associated with spontaneous abortion, with particular emphasis on PARP6, ISLR, ULK3, FGFRL1, TBC1D14, SCRIB, and PLEC.

CONCLUSION

We found variability in chromosomal abnormalities across clinical features, identifying eight crucial copy number variations (CNVs) and multiple key genes that may be linked to spontaneous abortion. This research enhances the comprehension of genetic factors contributing to spontaneous abortion.

Fetal and Neonatal Autopsy in the Molecular Age: Exploring Tissue Selection for Testing Success

While conventional autopsy is the gold-standard for determining cause of demise in the fetal and neonatal population, molecular analysis is increasingly used as an ancillary tool. Testing methods and tissue selection should be optimized to provide informative genetic results. This institutional review compares testing modalities and postmortem tissue type in 53 demises occurring between 20 weeks of gestation and 28 days of life. Testing success, defined as completion of analysis, varies by technique and may require viable cells for culture or extractable nucleic acid. Success was achieved by microarray in 29/30 tests (96.7%), karyotype in 40/54 tests (74.1%), fluorescent in situ hybridization in 5/9 tests (55.6%), and focused gene panels in 2/2 tests (100%). With respect to tissue type, postmortem prepartum amniotic fluid was analyzed to completion in 100% of tests performed; compared to 84.0%, 54.5%, and 80.8% of tests using placenta, fetal only, and mixed fetal-placental tissue collection, respectively. Sampling skin (83.3%, in cases with minimal maceration) and kidney (75.0%) were often successful, compared to lower efficacy of umbilical cord (57.1%) and liver (25.0%). Addition of genetic testing into cases with anomalous clinical and gross findings can increase the utility of the final report for family counseling and future pregnancy planning.

The application of the ICD-10 for antepartum stillbirth patients in a referral centre of Eastern China: a retrospective study from 2015 to 2022

BACKGROUND

The causes of some stillbirths are unclear, and additional work must be done to investigate the risk factors for stillbirths.

OBJECTIVE

To apply the International Classification of Disease-10 (ICD-10) for antepartum stillbirth at a referral center in eastern China.

METHODS

Antepartum stillbirths were grouped according to the cause of death according to the International Classification of Disease-10 (ICD-10) criteria. The main maternal condition at the time of antepartum stillbirth was assigned to each patient.

RESULTS

Antepartum stillbirths were mostly classified as fetal deaths of unspecified cause, antepartum hypoxia. Although more than half of the mothers were without an identified condition at the time of the antepartum stillbirth, where there was a maternal condition associated with perinatal death, maternal medical and surgical conditions and maternal complications during pregnancy were most common. Of all the stillbirths, 51.2% occurred between 28 and 37 weeks of gestation, the main causes of stillbirth at different gestational ages also differed. Autopsy and chromosomal microarray analysis (CMA) were recommended in all stillbirths, but only 3.6% received autopsy and 10.5% underwent chromosomal microarray analysis.

CONCLUSIONS

The ICD-10 is helpful in classifying the causes of stillbirths, but more than half of the stillbirths in our study were unexplained; therefore, additional work must be done. And the ICD-10 score may need to be improved, such as by classifying stillbirths according to gestational age. Autopsy and CMA could help determine the cause of stillbirth, but the acceptance of these methods is currently low.

Placental Pathology Findings in Unexplained Pregnancy Losses

There are approximately 5 million pregnancies per year in the USA, with 1 million ending in miscarriage (a loss occurring prior to 20 weeks of gestation) and over 20,000 ending in stillbirth at or beyond 20 weeks of gestation. As many as 50% of these losses are unexplained. Our objective was to evaluate the effect of expanding the placental pathology diagnostic categories to include the explicit categories of (1) dysmorphic chorionic villi and (2) small placenta in examining previously unexplained losses. Using a clinical database of 1256 previously unexplained losses at 6-43 weeks of gestation, the most prevalent abnormality associated with each loss was determined through examination of its placental pathology slides. Of 1256 cases analyzed from 922 patients, there were 878 (69.9%) miscarriages and 378 (30.1%) antepartum stillbirths. We determined the pathologic diagnoses for 1150/1256 (91.6%) of the entire series, 777/878 (88.5%) of the miscarriages (< 20 weeks' gestation), and 373/378 (98.7%) of the stillbirths (≥ 20 weeks' gestation). The most common pathologic feature observed in unexplained miscarriages was dysmorphic chorionic villi (757 cases; 86.2%), a marker associated with genetic abnormalities. The most common pathologic feature observed in unexplained stillbirths was a small placenta (128 cases; 33.9%). Our classification system reinforced the utility of placental examination for elucidating potential mechanisms behind pregnancy loss. The improved rate of diagnosis appeared to be the result of filling a gap in previous pregnancy loss classification systems via inclusion of the categories of dysmorphic chorionic villi and small placenta.

Non-invasive cell-free DNA-based approach for the diagnosis of clinical miscarriage: A retrospective study

OBJECTIVE

To evaluate cell-free DNA (cfDNA) testing as a non-invasive approach to detecting aneuploidies in clinical miscarriages.

DESIGN

A retrospective cohort study of women with pregnancy loss.

SETTING

Hospitals and genetic analysis laboratories.

POPULATION OR SAMPLE

Pregnancy losses in the period 2021-2022.

METHODS

Results derived from non-invasive cfDNA testing (Veriseq NIPT Solution V2) of maternal blood and invasive analysis of products of conception (POC) (Ion ReproSeq) compared in 120 women who suffered a miscarriage.

MAIN OUTCOME MEASURES

Concordance rate results, cfDNA testing performance, non-informative rate (NIR) and fetal fraction (FF).

RESULTS

We found no significant differences in the NIR between invasive (iPOC) and non-invasive (niPOC) analysis of POC (10.0% [12/120] versus 16.7% [20/120]). Of 120 samples, 90 provided an informative result in iPOC and niPOC groups (75%). cfDNA analysis correctly identified 74/87 (85.1%) samples (excluding triploidies). Sensitivity and specificity were 79.4% and 100%, respectively; all discordant cases were female. A binomial logistic model suggested fetal sex as the only variable influencing the concordance rate (P = 0.035). A Y-chromosome-based FF estimate allowed the optimal reclassification of cfDNA of non-informative male fetuses and a more accurate evaluation of cfDNA testing performance. The difference between the two FF estimates (native algorithm and Y-chromosome-based) suggests that female non-concordant cases may represent non-informative cases.

CONCLUSIONS

Cell-free DNA-based testing provides a non-invasive approach to determining the genetic cause of clinical miscarriage.

Estimation on risk of spontaneous abortions by genomic disorders from a meta-analysis of microarray results on large case series of pregnancy losses

A meta-analysis on seven large case series (>1000 cases) of chromosome microarray analysis (CMA) on products of conceptions (POC) evaluated the diagnostic yields of genomic disorders and syndromic pathogenic copy number variants (pCNVs) from a collection of 35,130 POC cases. CMA detected chromosomal abnormalities and pCNVs in approximately 50% and 2.5% of cases, respectively. The genomic disorders and syndromic pCNVs accounted for 31% of the detected pCNVs, and their incidences in POC ranged from 1/750 to 1/12,000. The newborn incidences of these genomic disorders and syndromic pCNVs were estimated in a range of 1/4000 to 1/50,000 live births from population genetic studies and diagnostic yields of a large case series of 32,587 pediatric patients. The risk of spontaneous abortion (SAB) for DiGeorge syndrome (DGS), Wolf-Hirschhorn syndrome (WHS), and William-Beuren syndrome (WBS) was 42%, 33%, and 21%, respectively. The estimated overall risk of SAB for major genomic disorders and syndromic pCNVs was approximately 38%, which was significantly lower than the 94% overall risk of SAB for chromosomal abnormalities. Further classification on levels of risk of SAB to high (>75%), intermediate (51%-75%), and low (26%-50%) for known chromosomal abnormalities, genomic disorders, and syndromic pCNVs could provide evidence-based interpretation in prenatal diagnosis and genetic counseling.

Sequential application of copy number variation sequencing and quantitative fluorescence polymerase chain reaction in genetic analysis of miscarriage and stillbirth

BACKGROUND

Copy number variation sequencing (CNV-seq) could detect most chromosomal abnormalities except polyploidy, and quantitative fluorescence polymerase chain reaction (QF-PCR) is a supplementary method to CNV-seq in triploid detection. This study aimed to evaluate the feasibility of sequential application of CNV-seq and QF-PCR in genetic analysis of miscarriage and stillbirth.

METHODS

A total of 261 fetal specimens were analyzed by CNV-seq, and QF-PCR was only further performed for samples with normal female karyotype identified by CNV-seq. Cost and turnaround time (TAT) was analyzed for sequential detection strategy. Subgroup analysis and logistic regression were carried out to evaluate the relationship between clinical characteristics (maternal age, gestational age, and number of pregnancy losses) and the occurrence of chromosomal abnormalities.

RESULTS

Abnormal results were obtained in 120 of 261 (45.98%) cases. Aneuploidy was the most common abnormality (37.55%), followed by triploidy (4.98%) and pathogenic copy number variations (pCNVs) (3.45%). CNV-seq could detect the triploidy with male karyotype, and QF-PCR could further identify the remaining triploidy with female karyotype. In this study, we found more male triploidies than female triploidies. With the same ability in chromosomal abnormalities detection, the cost of sequential strategy decreased by 17.35% compared with combined strategy. In subgroup analysis, significant difference was found in the frequency of total chromosomal abnormalities between early abortion group and late abortion group. Results of logistic regression showed a trend that pregnant women with advanced age, first-time abortion, and abortion earlier than 12 weeks were more likely to detect chromosomal aberrations in their products of conception.

CONCLUSION

Sequential application of CNV-seq and QF-PCR is an economic and practical strategy to identify chromosomal abnormalities in fetal tissue.

Copy number variants and fetal growth in stillbirths

BACKGROUND

Fetal growth abnormalities are associated with a higher incidence of stillbirth, with small and large for gestational age infants incurring a 3 to 4- and 2 to 3-fold increased risk, respectively. Although clinical risk factors such as diabetes, hypertension, and placental insufficiency have been associated with fetal growth aberrations and stillbirth, the role of underlying genetic etiologies remains uncertain.

OBJECTIVE

This study aimed to assess the relationship between abnormal copy number variants and fetal growth abnormalities in stillbirths using chromosomal microarray.

STUDY DESIGN

A secondary analysis utilizing a cohort study design of stillbirths from the Stillbirth Collaborative Research Network was performed. Exposure was defined as abnormal copy number variants including aneuploidies, pathogenic copy number variants, and variants of unknown clinical significance. The outcomes were small for gestational age and large for gestational age stillbirths, defined as a birthweight <10th percentile and greater than the 90th percentile for gestational age, respectively.

RESULTS

Among 393 stillbirths with chromosomal microarray and birthweight data, 16% had abnormal copy number variants. The small for gestational age outcome was more common among those with abnormal copy number variants than those with a normal microarray (29.5% vs 16.5%; P=.038). This finding was consistent after adjusting for clinically important variables. In the final model, only abnormal copy number variants and maternal age remained significantly associated with small for gestational age stillbirths, with an adjusted odds ratio of 2.22 (95% confidence interval, 1.12-4.18). Although large for gestational age stillbirths were more likely to have an abnormal microarray: 6.2% vs 3.3% (P=.275), with an odds ratio of 2.35 (95% confidence interval, 0.70-7.90), this finding did not reach statistical significance.

CONCLUSION

Genetic abnormalities are more common in the setting of small for gestational age stillborn fetuses. Abnormal copy number variants not detectable by traditional karyotype make up approximately 50% of the genetic abnormalities in this population.

A Novel System for the Detection of Spontaneous Abortion-Causing Aneuploidy and Its Erroneous Chromosome Origins through the Combination of Low-Pass Copy Number Variation Sequencing and NGS-Based STR Tests

During the period of 2018-2020, we first combined reported low-pass whole genome sequencing and NGS-based STR tests for miscarriage samples analysis. Compared with G-banding karyotyping, the system increased the detection rate of chromosomal abnormalities in miscarriage samples to 56.4% in 500 unexplained recurrent spontaneous abortions. In this study, a total of 386 STR loci were developed on twenty-two autosomes and two sex chromosomes (X and Y chromosomes), which can help to distinguish triploidy, uniparental diploidy and maternal cell contamination and can trace the parental origin of erroneous chromosomes. It is not possible to accomplish this with existing methods of detection in miscarriage samples. Among the tested aneuploid errors, the most frequently detected error was trisomy (33.4% in total and 59.9% in the error chromosome group). In the trisomy samples, 94.7% extra chromosomes were of maternal origin and 5.31% were of paternal origin. This novel system improves the genetic analysis method of miscarriage samples and provides more reference information for clinical pregnancy guidance.

Case Report: Novel compound heterozygous variants in CHRNA1 gene leading to lethal multiple pterygium syndrome: A case report

Background: Lethal multiple pterygium syndrome (LMPS) is a rare autosomal recessive inherited disorder typically characterized by intrauterine growth retardation, multiple pterygia, and flexion contractures.

Case presentation: We herein report a Chinese case with a history of three adverse pregnancies demonstrating the same ultrasonic phenotypes, including increased nuchal translucency, edema, fetal neck cystoma, reduced movement, joint contractures, and other congenital features. Whole-exome sequencing (WES) revealed novel compound heterozygous variants in the CHRNA1 gene NM_000079.4: c.[1128delG (p.Pro377LeufsTer10)]; [505T>C (p.Trp169Arg)] in the recruited individual, and subsequent familial segregation showed that both parents transmitted their respective mutation.

Conclusion: For the first time, we identified an association between the CHRNA1 gene and the recurrent lethal multiple pterygium syndrome (LMPS) in a Chinese family. This finding may also enrich the mutation spectrum of the CHRNA1 gene and promote the applications of WES technology in etiologic diagnosis of ultrasound anomalies in prenatal examination.

Investigation and management of stillbirth: a descriptive review of major guidelines

Stillbirth is a common and devastating pregnancy complication. The aim of this study was to review and compare the recommendations of the most recently published guidelines on the investigation and management of this adverse outcome. A descriptive review of guidelines from the American College of Obstetricians and Gynecologists (ACOG), the Royal College of Obstetricians and Gynecologists (RCOG), the Perinatal Society of Australia and New Zealand (PSANZ), the Society of Obstetricians and Gynecologists of Canada (SOGC) on stillbirth was carried out. Regarding investigation, there is consensus that medical history and postmortem examination are crucial and that determining the etiology may improve care in a subsequent pregnancy. All guidelines recommend histopathological examination of the placenta, genetic analysis and microbiology of fetal and placental tissues, offering less invasive techniques when autopsy is declined and a Kleihauer test to detect large feto-maternal hemorrhage, whereas they discourage routine screening for inherited thrombophilias. RCOG and SOGC also recommend a complete blood count, coagulopathies' testing, anti-Ro and anti-La antibodies' measurement in cases of hydrops and parental karyotyping. Discrepancies exist among the reviewed guidelines on the definition of stillbirth and the usefulness of thyroid function tests and maternal viral screening. Moreover, only ACOG and RCOG discuss the management of stillbirth. They agree that, in the absence of coagulopathies, expectant management should be considered and encourage vaginal birth, but they suggest different labor induction protocols and different management in subsequent pregnancies. It is important to develop consistent international practice protocols, in order to allow effective determination of the underlying causes and optimal management of stillbirths, while identifying the gaps in the current literature may highlight the need for future research.

Chromosomal Copy Number Variation Analysis in Pregnancy Products from Recurrent and Sporadic Miscarriage Using Next-Generation Sequencing

Chromosomal abnormality is one of the causes of fetal miscarriage. The potential differences of fetal chromosomal abnormalities in sporadic miscarriage (SM) and recurrent miscarriage (RM) remain unclear. The purpose of this study was to investigate copy number variations (CNVs) in SM and RM to provide useful genetic guidance for pregnancy and prenatal diagnosis. Four hundred eight samples of aborted fetuses were analyzed by CNV sequencing, and further functional enrichment analysis was performed. Chromosomal abnormalities were identified in 218 (53.4%) fetuses. There were 62 cases (15.2%) with structural chromosomal abnormalities, including 41 with VUS CNVs, 8 with pathogenic CNVs (pCNVs), and 5 with likely pCNVs. Duplications or deletions of 7p22, 8p22, 8p23, and Xp22.31 were significantly more common in RM cases and therefore believed to be related to RM. A total of 289 genes were identified, and 29 different functions were enriched as potential RM candidate genes and functions, which were mainly concentrated in 4 functional categories: chemokines and chemotaxis, protease activity and protein modification, defense response to bacterial and fungal infections, and immune response. The results of this study may improve our understanding of the etiology of RM and contribute to the establishment of a population-based genetic marker information for RM.

Analysis of Genomic Copy Number Variation in Miscarriages During Early and Middle Pregnancy

The purpose of this study was to explore the copy number variations (CNVs) associated with miscarriage during early and middle pregnancy and provide useful genetic guidance for pregnancy and prenatal diagnosis. A total of 505 fetal specimens were collected and CNV sequencing (CNV-seq) analysis was performed to determine the types and clinical significance of CNVs, and relevant medical records were collected. The chromosomal abnormality rate was 54.3% (274/505), among which the numerical chromosomal abnormality rate was 40.0% (202/505) and structural chromosomal abnormality rate was 14.3% (72/505). Chromosomal monosomy mainly occurred on sex chromosomes, and chromosomal trisomy mainly occurred on chromosomes 16, 22, 21, 15, 13, and 9. The incidence of numerical chromosomal abnormalities in ≥35 year-old age pregnant women was significantly higher than <35 year-old age group. The highest incidence of pathogenic CNV (pCNV) was found in fetuses at ≤6 weeks of pregnancy (5.26%), and the incidence of variants of unknown significance (VOUS) CNVs decreased gradually with the increase of gestational age. The rate of chromosomal abnormalities of fetuses in early pregnancy (59.5%) was higher than that of fetuses in middle pregnancy (27.2%) (p < 0.001). There were 168 genes in VOUS + pCNV regions. 41 functions and 12 pathways (p < 0.05) were enriched of these genes by Gene Ontology (GO) analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis. Some meaningful genetic etiology information such as genes and pathways has been obtained, it may provide useful genetic guidance for pregnancy and prenatal diagnosis.

Have maternal or paternal ages any impact on the prenatal incidence of genomic copy number variants associated with fetal structural anomalies?

The objective of this study was to determine whether maternal or paternal ages have any impact on the prenatal incidence of genomic copy number variants (CNV) in fetuses with structural anomalies. We conducted a non-paired case-control study (1:2 ratio) among pregnancies undergoing chromosomal microarray analysis (CMA) because of fetal ultrasound anomalies, from December 2012 to May 2020. Pregnancies with any pathogenic copy number variant (CNV), either microdeletion or microduplication, were defined as cases. Controls were selected as the next two pregnancies with the same indication for CMA but with a normal result. Logistic regression was used, adjusting by use of assisted reproductive technology (ART) and parental smoking. Stratified analysis was performed according to CNV type (de novo/inherited and recurrent/non-recurrent). The study included 189 pregnancies: 63 cases and 126 controls. Mean maternal age in cases was 33.1 (SD 4.6) years and 33.9 (SD 6.0) years in controls. Mean paternal mean age was 34.5 (SD 4.8) years in cases and 35.8 (SD 5.8) years in controls. No significant differences in maternal or paternal age were observed, neither in stratified analysis according to the CNV type. Moreover, the proportion of cases were not significantly different between non-advanced and advanced ages, either considering paternal or maternal ages. The presence of pathogenic CNV at CMA in fetuses with structural anomalies was not found to be associated with advanced paternal or maternal age.

Follow-up in Patients With Non-invasive Prenatal Screening Failures: A Reflection on the Choice of Further Prenatal Diagnosis

Background

Our aim was to provide a theoretical basis for clinicians to conduct genetic counseling and choose further prenatal diagnosis methods for pregnant women who failed non-invasive prenatal screening (NIPS).

Methods

A retrospective analysis was performed on pregnant women who had failed NIPS tests.

Results

Among the 123,291 samples, 394 pregnant women did not obtain valid results due to test failures. A total of 378 pregnant women were available for follow-up, while 16 patients were lost to follow-up. Of these 378, 135 pregnant women chose further prenatal diagnosis through amniocentesis, and one case of dysplasia was recalled for postpartum chromosome testing. The incidence rate of congenital chromosomal abnormalities in those who failed the NIPS was 3.97% (15/378), which was higher than that of the chromosomal abnormalities in the common population (1.8%). Among the pregnant women who received prenatal diagnosis, the positive rates of chromosomal abnormalities in the chromosomal microarray analysis/copy number variation sequencing (CMA/CNV-seq) group and in the karyotyping group were 15.28 and 4.76%, respectively.

Conclusion

Prenatal diagnosis should be strongly recommended in posttest genetic counseling for pregnant women with NIPS failures. Further, high-resolution detection methods should be recommended for additional prenatal diagnoses.

Cardio-pathogenic variants in unexplained intrauterine fetal death: a retrospective pilot study

To describe the prevalence and spectrum of cardio-pathogenic variants in singleton fetuses after unexplained intrauterine fetal death (IUFD). DNA from post-mortem fibroblastic tissue samples of 16 fetuses after unexplained IUFD was retrieved at two tertiary university hospitals for clinical exome sequencing with subsequent filtering of 122 cardio-specific genes to elucidate underlying cardio-pathogenic variants. In total, we included 12 (75%) male and four (25%) female fetuses who were stillborn at a median gestational age of 34⁺⁶ (23⁺²–40⁺⁵) weeks. In two (12.5%) fetuses no cardio-pathogenic variants were found. In 14 (87.5%) fetuses, overall 33 variants were detected in 22 cardio-specific genes, involving 14 (63.63%) genes associated with cardiomyopathy, six (27.27%) arrhythmogenic susceptibility genes and two (9.09%) arrhythmia and cardiomyopathy associated genes. Among the 33 variants, five (15.2%) were classified as likely benign according to the American College of Medical Genetics and Genomics; 28 (84.8%) variants were considered as variants of uncertain significance. Compared to a cohort of explained IUFDs, the cases with and without fetal variants in cardiac genes differed not significantly regarding maternal age, previous history of stillbirth, time of stillbirth or fetal sex. Unexplained stillbirth may be caused by cardio-genetic pathologies, yet a high number of variants of uncertain significance merit a more detailed post-mortem examination including family segregation analysis.

Management of Stillbirth: Obstetric Care Consensus No, 10

Stillbirth is one of the most common adverse pregnancy outcomes, occurring in 1 in 160 deliveries in the United States. In developed countries, the most prevalent risk factors associated with stillbirth are non-Hispanic black race, nulliparity, advanced maternal age, obesity, preexisting diabetes, chronic hypertension, smoking, alcohol use, having a pregnancy using assisted reproductive technology, multiple gestation, male fetal sex, unmarried status, and past obstetric history. Although some of these factors may be modifiable (such as smoking), many are not. The study of specific causes of stillbirth has been hampered by the lack of uniform protocols to evaluate and classify stillbirths and by decreasing autopsy rates. In any specific case, it may be difficult to assign a definite cause to a stillbirth. A significant proportion of stillbirths remains unexplained even after a thorough evaluation. Evaluation of a stillbirth should include fetal autopsy; gross and histologic examination of the placenta, umbilical cord, and membranes; and genetic evaluation. The method and timing of delivery after a stillbirth depend on the gestational age at which the death occurred, maternal obstetric history (eg, previous hysterotomy), and maternal preference. Health care providers should weigh the risks and benefits of each strategy in a given clinical scenario and consider available institutional expertise. Patient support should include emotional support and clear communication of test results. Referral to a bereavement counselor, peer support group, or mental health professional may be advisable for management of grief and depression.

Obstetric Care Consensus #10: Management of Stillbirth: (Replaces Practice Bulletin Number 102, March 2009)

Stillbirth is one of the most common adverse pregnancy outcomes, occurring in 1 in 160 deliveries in the United States. In developed countries, the most prevalent risk factors associated with stillbirth are non-Hispanic black race, nulliparity, advanced maternal age, obesity, preexisting diabetes, chronic hypertension, smoking, alcohol use, having a pregnancy using assisted reproductive technology, multiple gestation, male fetal sex, unmarried status, and past obstetric history. Although some of these factors may be modifiable (such as smoking), many are not. The study of specific causes of stillbirth has been hampered by the lack of uniform protocols to evaluate and classify stillbirths and by decreasing autopsy rates. In any specific case, it may be difficult to assign a definite cause to a stillbirth. A significant proportion of stillbirths remains unexplained, even after a thorough evaluation. Evaluation of a stillbirth should include fetal autopsy; gross and histologic examination of the placenta, umbilical cord, and membranes; and genetic evaluation. The method and timing of delivery after a stillbirth depend on the gestational age at which the death occurred, maternal obstetric history (eg, previous hysterotomy), and maternal preference. Health care providers should weigh the risks and benefits of each strategy in a given clinical scenario and consider available institutional expertise. Patient support should include emotional support and clear communication of test results. Referral to a bereavement counselor, peer support group, or mental health professional may be advisable for management of grief and depression.

Cytogenetic Investigation in 136 Consecutive Stillbirths: Does the Tissue Type Affect the Success Rate of Chromosomal Microarray Analysis and Karyotype?

BACKGROUND

Chromosomal anomalies are a recognized cause of stillbirth, accounting for 6-17% of the cases. As a diagnostic laboratory method in this setting, conventional karyotyping has two main drawbacks: the need for viable fetal cells in a dead fetus and its limited resolution as compared to alternative techniques.

OBJECTIVE

To assess the effectiveness of cytogenetic analysis in stillbirths between different testing methods and different sampled tissues.

METHODS

From 2011 to 2017, 145 stillborn fetuses (defined as fetal losses after 22 weeks) were delivered in our center. The stillbirth protocol includes genetic testing by means of a karyotype, QF-PCR, or chromosomal microarray analysis (CMA), depending on the presence of fetal structural anomalies and the study time period. The success rates were compared between tests and between different sampled tissues.

RESULTS

Consent was granted for cytogenetic analysis in 136 stillbirths. Test success rate was 100% (38/38) for CMA independent of the sampled tissue, 99% (65/66) for QF-PCR, and 66% (65/98) for karyotyping. The success rate for karyotyping was 48% (69/145) of the total tissues samples, showing great variation according to the tissue sampled: 83% (40/48) in amniotic fluid, 78% (21/27) in the placenta, 13% (7/54) in fetal skin, and 6.3% (1/16) in fetal blood. Four full or partial aneuploidies (trisomy 9, trisomy 22, tetrasomy 18p, and monosomy X) and 2 microdeletions (del2p16.3 and del1q13.2q13.4) were found, resulting in a 3.9% (4/103) prevalence for full or partial aneuploidy and a 5.3% prevalence (2/38) for submicroscopic abnormalities.

CONCLUSIONS

Amniotic fluid should be the preferred tissue source in the cytogenetic analysis of stillbirth due to its high success rate. Between tests, CMA is a preferable method because of its higher test success rate, independent of the sampled tissue, and higher diagnostic yield including chromosomal and submicroscopic anomalies.