Cytogenetic Analysis After Evaluation of 750 Fetal Deaths: Proposal for Diagnostic Workup

Induction of labor compared to dilation and evacuation for postmortem analysis

OBJECTIVE

This study aimed to evaluate the ability to obtain autopsy and cytogenetics after midtrimester termination.

METHODS

A retrospective cohort study of women undergoing termination, via induction or dilation and evacuation (D&E), at 16 0/7-23 6/7 weeks was performed. Exclusion criteria were elective termination, preterm labor, PPROM, and no autopsy or cytogenetic exam performed. The ability to obtain cytogenetics and autopsy as well as complications rates were compared between the two groups with Chi-square tests.

RESULTS

Of the 469 women who met the inclusion criteria, 158 had an induction and 312 had a D&E. The induction of labor group had higher mean gestational ages, p < 0.01. Successful autopsy was more likely in the induction group, 94.3%, versus D&E group, 34.7%, p = 0.01. There was no difference in ability to obtain cytogenetics between the two groups, 89.1% in the induction group, and 92.3% in D&E group, p = 0.4. There was a difference in the total complication rates between the groups, 9.8% (26) in the induction versus 6.4% (20) in the D&E group, p < 0.01; however, there was no difference in major complications.

CONCLUSIONS

Midtrimester terminations by induction were more likely to have successful autopsies when compared with D&E. The ability to obtain cytogenetics was similar regardless of termination mode.

Best diagnostic approach for the genetic evaluation of fetuses after intrauterine death in first, second or third trimester: QF-PCR, karyotyping and/or genome wide SNP array analysis

BACKGROUND

The aim of this study was to evaluate the best diagnostic approach for the genetic analysis of samples from first, second and third trimester intrauterine fetal deaths (IUFDs). We examined a total of 417 IUFD samples from fetuses with and without congenital anomalies. On 414 samples, karyotyping (N = 46) and/or rapid aneuploidy testing by QF-PCR (N = 371) was performed). One hundred sixty eight samples with a normal test result were subsequently tested by genome wide Single Nucleotide Polymorphism (SNP) array analysis. Three samples were only analyzed by array.

RESULTS

In 50 (12.0%) samples an aneuploidy was detected by QF-PCR and/or karyotyping, representing 47.1% of first, 13.2% of second and 3.4% of third trimester pregnancies. Karyotyping and QF-PCR failed in 4 (8.7%) and 7 (1.9%) samples, respectively, concerning mostly contaminated amniotic fluid samples from third trimester pregnancies.Clinically relevant aberrations were identified in 4.2% (all fetuses with malformations) of the 168 samples tested by SNP array. Inherited copy number variants (CNVs) were detected in 5.4% and 8.9% showed CNVs of unknown clinical relevance as parental inheritance could not be studied yet. In a sample from a fetus suspect for Meckel-Grüber syndrome, the genotype information from the SNP array revealed various stretches of homozygosity, including one stretch encompassing the CEP290 gene. Subsequent CEP290 mutation analysis revealed a homozygous, pathogenic mutation in this gene.

CONCLUSIONS

Based on our experience we recommend QF-PCR as the first-line test in IUFD samples of first and second trimester pregnancies to exclude aneuploidy before performing array analysis. The chance to detect aneuploidy in third trimester pregnancies is relatively low and therefore array analysis can be performed as a first-tier test. A tissue sample, instead of amniotic fluid, is preferred because of a higher success rate in testing.We emphasize the need for analysis of parental samples whenever a rare, unique CNV is detected to allow for better interpretation of such findings and to improve future pregnancy management. Furthermore, we illustrate the strength of SNP arrays for genotype analysis, even though we realize it is crucial to have detailed phenotypic information to make optimal use of the genotype data in finding candidate recessive genes that may be related to the fetal phenotype.

Sharing experiences to improve bereavement support and clinical care after stillbirth: report of the 7th annual meeting of the International Stillbirth Alliance

Stillbirth remains a global health challenge which is greatly affected by social and economic inequality, particularly the availability and quality of maternity care. The International Stillbirth Alliance (ISA) exists to raise awareness of stillbirth and to promote global collaboration in the prevention of stillbirth and provision of appropriate care for parents whose baby is stillborn. The focus of this ISA conference was to share experiences to improve bereavement support and clinical care. These issues, relevant throughout the globe, are not discrete but closely interrelated, with both similarities and differences depending on the specific country and cultural context. Counting stillbirths and understanding the causes of stillbirth are essential not only for providing optimal care and support to parents whose babies die, but also for reducing the future burden of stillbirth. This summary highlights novel work from obstetricians, midwives, psychologists, parents and peer support organizations that was presented at the ISA meeting. It covers topics including the bereavement process, peer support for parents, support and training for staff, evidence for clinical care, and the need for accurate data on stillbirths and perinatal audits. Representatives from the maternity services of the region presented their outcome data and shared their experiences of clinical and bereavement care. Data and developments in practice within stillbirth and bereavement care must be widely disseminated and acted upon by those responsible for maternity care provision, both to prevent stillbirths and to provide high-quality care when they do occur.

Karyotype versus microarray testing for genetic abnormalities after stillbirth

BACKGROUND

Genetic abnormalities have been associated with 6 to 13% of stillbirths, but the true prevalence may be higher. Unlike karyotype analysis, microarray analysis does not require live cells, and it detects small deletions and duplications called copy-number variants.

METHODS

The Stillbirth Collaborative Research Network conducted a population-based study of stillbirth in five geographic catchment areas. Standardized postmortem examinations and karyotype analyses were performed. A single-nucleotide polymorphism array was used to detect copy-number variants of at least 500 kb in placental or fetal tissue. Variants that were not identified in any of three databases of apparently unaffected persons were then classified into three groups: probably benign, clinical significance unknown, or pathogenic. We compared the results of karyotype and microarray analyses of samples obtained after delivery.

RESULTS

In our analysis of samples from 532 stillbirths, microarray analysis yielded results more often than did karyotype analysis (87.4% vs. 70.5%, P<0.001) and provided better detection of genetic abnormalities (aneuploidy or pathogenic copy-number variants, 8.3% vs. 5.8%; P=0.007). Microarray analysis also identified more genetic abnormalities among 443 antepartum stillbirths (8.8% vs. 6.5%, P=0.02) and 67 stillbirths with congenital anomalies (29.9% vs. 19.4%, P=0.008). As compared with karyotype analysis, microarray analysis provided a relative increase in the diagnosis of genetic abnormalities of 41.9% in all stillbirths, 34.5% in antepartum stillbirths, and 53.8% in stillbirths with anomalies.

CONCLUSIONS

Microarray analysis is more likely than karyotype analysis to provide a genetic diagnosis, primarily because of its success with nonviable tissue, and is especially valuable in analyses of stillbirths with congenital anomalies or in cases in which karyotype results cannot be obtained. (Funded by the Eunice Kennedy Shriver National Institute of Child Health and Human Development.).

Post-mortem examination after stillbirth: views of UK-based practitioners

OBJECTIVES

Worldwide, around four million stillbirths occur annually. The UK was recently ranked as 33rd out of 35 developed nations for stillbirth rates. The reasons for many stillbirths remain unexplained. Post-mortem examination (PME) can provide information for grieving families, and for future pregnancies. Rates of consent for PME are decreasing in the UK. The views of professionals may influence their approach to bereaved families, and, therefore, rates of consent. Arguably, obtaining qualitative insights into emotive areas such as PME from large numbers of practitioners is increasingly possible as electronic surveys become more sophisticated. Therefore we aimed to describe, using electronic media, the views of UK obstetricians, midwives and perinatal pathologists about PME for stillbirth.

STUDY DESIGN

10,000 UK midwives, 1136 UK obstetricians and all 40 UK perinatal pathologists received a link to an Internet survey via their professional organizations. A box was included for free-text responses. Iterative thematic analysis generated five themes and a 'line of argument' synthesis.

RESULTS

683 midwives, 98 obstetricians, and 11 perinatal pathologists provided open comments, generating five themes and the following line of argument: both professional views and family decision-making about postmortem after stillbirth are affected by the education and training of staff, local resources, and the quality of information available. All of these structural issues are interpreted by individual staff, women and families through personal beliefs and emotions, and professional and social discourses.

CONCLUSIONS

Internet-based surveys can generate valuable qualitative data. Effective decision-making for post-mortem after stillbirth may be improved by the introduction of user-friendly information and consent procedures, and staff training that takes account of existing innovations, and of the emotions and prior experiences of both staff and parents.

Prenatal detection of aneuploidy and imbalanced chromosomal arrangements by massively parallel sequencing

Fetal chromosomal abnormalities are the most common reasons for invasive prenatal testing. Currently, G-band karyotyping and several molecular genetic methods have been established for diagnosis of chromosomal abnormalities. Although these testing methods are highly reliable, the major limitation remains restricted resolutions or can only achieve limited coverage on the human genome at one time. The massively parallel sequencing (MPS) technologies which can reach single base pair resolution allows detection of genome-wide intragenic deletions and duplication challenging karyotyping and microarrays as the tool for prenatal diagnosis. Here we reported a novel and robust MPS-based method to detect aneuploidy and imbalanced chromosomal arrangements in amniotic fluid (AF) samples. We sequenced 62 AF samples on Illumina GAIIx platform and with averagely 0.01× whole genome sequencing data we detected 13 samples with numerical chromosomal abnormalities by z-test. With up to 2× whole genome sequencing data we were able to detect microdeletion/microduplication (ranged from 1.4 Mb to 37.3 Mb of 5 samples from chorionic villus sampling (CVS) using SeqSeq algorithm. Our work demonstrated MPS is a robust and accurate approach to detect aneuploidy and imbalanced chromosomal arrangements in prenatal samples.

Evaluation of 1025 fetal deaths: proposed diagnostic workup

OBJECTIVE

We sought to evaluate the contribution of different diagnostic tests for determining cause of fetal death. Our goal was to propose a workup guideline.

STUDY DESIGN

In a multicenter prospective cohort study from 2002 through 2008, for 1025 couples with fetal death ≥20 weeks' gestation, an extensive nonselective diagnostic workup was performed. A panel classified cause and determined contribution of diagnostics for allocating cause.

RESULTS

A Kleihauer-Betke, autopsy, placental examination, and cytogenetic analysis were abnormal in 11.9% (95% confidence interval [CI], 9.8-14.2), 51.5% (95% CI, 47.4-55.2), 89.2% (95% CI, 87.2-91.1), and 11.9% (95% CI, 8.7-15.7), respectively. The most valuable tests for determination of cause were placental examination (95.7%; 95% CI, 94.2-96.8), autopsy (72.6%; 95% CI, 69.2-75.9), and cytogenetic analysis (29.0%; 95% CI, 24.4-34.0).

CONCLUSION

Autopsy, placental examination, cytogenetic analysis, and testing for fetal maternal hemorrhage are basic tests for workup after fetal death. Based on the results of these tests or on specific clinical characteristics, further sequential testing is indicated.

Causes of death among stillbirths

CONTEXT

Stillbirth affects 1 in 160 pregnancies in the United States, equal to the number of infant deaths each year. Rates are higher than those of other developed countries and have stagnated over the past decade. There is significant racial disparity in the rate of stillbirth that is unexplained.

OBJECTIVE

To ascertain the causes of stillbirth in a population that is diverse by race/ethnicity and geography.

DESIGN, SETTING, AND PARTICIPANTS

A population-based study from March 2006 to September 2008 with surveillance for all stillbirths at 20 weeks or later in 59 tertiary care and community hospitals in 5 catchment areas defined by state and county boundaries to ensure access to at least 90% of all deliveries. Termination of a live fetus was excluded. Standardized evaluations were performed at delivery.

MAIN OUTCOME MEASURES

Medical history, fetal postmortem and placental pathology, karyotype, other laboratory tests, systematic assignment of causes of death.

RESULTS

Of 663 women with stillbirth enrolled, 500 women consented to complete postmortem examinations of 512 neonates. A probable cause of death was found in 312 stillbirths (60.9%; 95% CI, 56.5%-65.2%) and possible or probable cause in 390 (76.2%; 95% CI, 72.2%-79.8%). The most common causes were obstetric conditions (150 [29.3%; 95% CI, 25.4%-33.5%]), placental abnormalities (121 [23.6%; 95% CI, 20.1%-27.6%]), fetal genetic/structural abnormalities (70 [13.7%; 95% CI, 10.9%-17.0%]), infection (66 [12.9%; 95% CI, 10.2%-16.2%]), umbilical cord abnormalities (53 [10.4%; 95% CI, 7.9%-13.4%]), hypertensive disorders (47 [9.2%; 95% CI, 6.9%-12.1%]), and other maternal medical conditions (40 [7.8%; 95% CI, 5.7%-10.6%]). A higher proportion of stillbirths in non-Hispanic black women compared with non-Hispanic white and Hispanic ones was associated with obstetric complications (43.5% [50] vs 23.7% [85]; difference, 19.8%; 95% CI, 9.7%-29.9%; P < .001) and infections (25.2% [29] vs 7.8% [28]; difference, 17.4%; 95% CI, 9.0%-25.8%; P < .001). Stillbirths occurring intrapartum and early in gestation were more common in non-Hispanic black women. Sources most likely to provide positive information regarding cause of death were placental histology (268 [52.3%; 95% CI, 47.9%-56.7%]), perinatal postmortem examination (161 [31.4%; 95% CI, 27.5%-35.7%]), and karyotype (32 of 357 with definitive results [9%; 95% CI, 6.3%-12.5%]).

CONCLUSIONS

A systematic evaluation led to a probable or possible cause in the majority of stillbirths. Obstetric conditions and placental abnormalities were the most common causes of stillbirth, although the distribution differed by race/ethnicity.

Genome-wide array-based copy number profiling in human placentas from unexplained stillbirths

OBJECTIVE

Accumulating evidence suggests that genomic structural variations, particularly copy number variations (CNV), are a common occurrence in humans that may bear phenotypic consequences for living individuals possessing the variant. While precise estimates vary, large-scale karyotypic abnormalities are present in 6-12% of stillbirths (SB). However, due to inherent limitations of conventional cytogenetics, the contribution of genomic aberrations to stillbirth is likely underrepresented. High-resolution copy number variant analysis by genomic array-based profiling may overcome such limitations.

METHODS

Prospectively acquired SB cases > 22 weeks underwent classification of 'unexplained' stillbirth by Wigglesworth and Aberdeen criteria after extensive testing and rigorous multidisciplinary audit. Genome-wide analysis was conducted using high-resolution Illumina single nucleotide polymorphism (SNP) arrays (Human CNV370-Duo) on placental and fetal samples. Potential alternate detection methods were completed by one or more of three independent means (quantitative PCR, Illumina1M, or Agilent105K comparative genomic hybridization arrays).

RESULTS

In our cohort of 54 stillbirths, 29 met strict unexplained criteria. Among these, we identified 24 putative novel CNVs. Subsequent interrogation detected 18 of 24 CNVs (75%) in placental samples, 8 of which were also confirmed in available fetal samples; none were present in maternal blood.

CONCLUSION

We describe the potential of whole-genome placental profiling to identify small genomic imbalances, which might contribute to a small proportion of well-characterized, unexplained stillbirths.

Cytogenetic analysis of 355 cases of fetal loss in different trimesters

OBJECTIVE

We estimated the success rates of cytogenetic analyses in different tissue samples after intrauterine fetal deaths and analyzed the value of cytogenetic testing for determining the causes.

METHODS

Women with intrauterine fetal deaths (occurring at > 10 weeks of gestation) were offered either invasive testing before medical induction of labor, or solid tissue biopsy diagnosis after delivery.

RESULTS

A total cohort of 355 intrauterine fetal deaths was studied. During antepartum examinations, invasive procedures included amniocentesis (AMC), chorionic villus sampling (CVS) and umbilical cord (UBC) sampling. During postpartum examinations, samples were taken from unfixed specimens of fetal skin, placenta and other tissues. Chromosomal abnormalities were observed in 22 fetal deaths for which cytogenetic analyses were successful. Logistic regression analysis identified antepartum invasive sampling [P = 0.000, odds ratio (OR) 31.125, 95% confidence interval (CI) 14.265-67.908] to be associated with a high cytogenetic success rate and older age with fetal deaths (P = 0.104, OR 0.487, 95% CI 0.204-1.160) not to be associated with a high chromosomal abnormality. In the patients with recurrent pregnancy loss, the chromosomal abnormality rate of 18.6% of spontaneous abortions has not been significantly more than that of fetal deaths 11.5% (P = 0.437).

CONCLUSION

Parents should be counseled on all aspects of cytogenetic analysis after fetal death. Antepartum testing after pregnancy loss is recommended.

Genetics of stillbirth

Approximately 25% of stillbirths have been attributed to genetic etiologies. The most common cytogenetic abnormalities are similar to those seen in liveborns and include 45X, trisomy 21, trisomy 18, and trisomy 13. Cytogenetic abnormalities are more common when fetal structural anomalies are identified. Mendelian and metabolic causes of stillbirth are less well understood although single gene disorders can result in stillbirth. With new cytogenetic and molecular technologies additional genetic causes of stillbirth are likely to be described and will provide additional information for appropriate genetic counseling.

Stillbirth: fetal disorders

Fetal disorders (including congenital malformations) are among the most frequent of causes of intrauterine death. Assessment to detect fetal processes is straightforward: history (prenatal, perinatal, and family); external clinical examination; photographs; whole body radiographs; cytogenetic investigation; and internal necropsy. Unfortunately such investigations are profoundly underused. When appropriately and nonselectively assessed, about one-fifth of all stillborn infants will be found to have a fetal cause of their death. Fetal diagnoses are markedly heterogeneous, with no single process accounting for more than 1.5% of all fetal deaths. Identifying a fetal cause has marked implications for the family and changes some elements of counseling and care in more than half of those whose stillborn infants were adequately evaluated. Currently unmet needs include research needs including efforts to understand the variability of intrauterine effects of fetal disorders and their causes, and clinical needs, particularly related to funding for evaluation of stillborns and development of geographically dispersed multidisciplinary commitment and expertise devoted to stillbirth evaluation.

Trisomy 9 mosaicism diagnosed in utero

We present three cases of trisomy 9 mosaicism diagnosed by amniocentesis with ongoing pregnancies after referral to our center due to fetal abnormalities. Two cases were associated with severe fetal growth restriction (FGR), each of which resulted in an intrauterine fetal demise (IUFD) in the third trimester. The other case involved mild FGR with a congenital diaphragmatic hernia and resulted in a live birth with severe development delay. A major prenatal finding of trisomy 9 mosaicism is FGR. Fetuses with trisomy 9 mosaicism can rarely survive in the case of severe FGR.

Stillbirth classification--developing an international consensus for research: executive summary of a National Institute of Child Health and Human Development workshop

Stillbirth is a major obstetric complication, with 3.2 million stillbirths worldwide and 26,000 stillbirths in the United States every year. The Eunice Kennedy Shriver National Institute of Child Health and Human Development held a workshop from October 22-24, 2007, to review the pathophysiology of conditions underlying stillbirth to define causes of death. The optimal classification system would identify the pathophysiologic entity initiating the chain of events that irreversibly led to death. Because the integrity of the classification is based on available pathologic, clinical, and diagnostic data, experts emphasized that a complete stillbirth workup should be performed. Experts developed evidence-based characteristics of maternal, fetal, and placental conditions to attribute a condition as a cause of stillbirth. These conditions include infection, maternal medical conditions, antiphospholipid syndrome, heritable thrombophilias, red cell alloimmunization, platelet alloimmunization, congenital malformations, chromosomal abnormalities including confined placental mosaicism, fetomaternal hemorrhage, placental and umbilical cord abnormalities including vasa previa and placental abruption, complications of multifetal gestation, and uterine complications. In all cases, owing to lack of sufficient knowledge about disease states and normal development, there will be a degree of uncertainty regarding whether a specific condition was indeed the cause of death.

The clinical content of preconception care: reproductive history

A history of previous birth of a low birthweight infant, previous cesarean sections, multiple previous spontaneous abortions, prior stillbirth, or uterine anomaly identifies women at increased risk for recurrent abortion, preterm birth, or stillbirth. We review the evidence for the potential benefit of reproductive history in identifying strategies for evaluation and treatment to prevent recurrent adverse pregnancy outcome. We offer evidence-based recommendations for management of women with these histories.