Genomics and perinatal care

Study protocol: childhood outcomes of fetal genomic variants: the PrenatAL Microarray (PALM) cohort study

BACKGROUND

The implementation of genomic testing in pregnancy means that couples have access to more information about their child's genetic make-up before birth than ever before. One of the resulting challenges is the management of genetic variations with unclear clinical significance. This population-based study will help to close this critical knowledge gap through a multidisciplinary cohort study of children with and without genomic copy number variants (CNVs) diagnosed before birth. By comparing children with prenatally-ascertained CNVs to children without a CNV, we aim to (1) examine their developmental, social-emotional and health status; (2) measure the impact of prenatal diagnosis of a CNV on maternal perceptions of child health, behavior and development; and (3) determine the proportion of prenatally-ascertained CNVs of unknown or uncertain significance that are reclassified as benign or pathogenic after 2 or more years.

METHODS

This study will establish and follow up a cohort of mother-child pairs who have had a prenatal diagnosis with a chromosomal microarray from 2013-2019 in the Australian state of Victoria. Children aged 12 months to 7 years will be assessed using validated, age-appropriate measures. The primary outcome measures will be the Wechsler Preschool and Primary Scale of Intelligence IV (WPSSI-IV) IQ score (2.5 to 7 year old's), the Ages and Stages Questionnaire (12-30 months old), and the Brief Infant- Toddler Social and Emotional Assessment (BITSEA) score. Clinical assessment by a pediatrician will also be performed. Secondary outcomes will be scores obtained from the: Vineland Adaptive Behavior Scale, Maternal Postnatal Attachment Questionnaire, the Vulnerable Child Scale, Profile of Mood States, Parent Sense of Competence Scale. A descriptive analysis of the reclassification rates of CNVs after ≥2 years will be performed.

DISCUSSION

This study protocol describes the first Australian cohort study following children after prenatal diagnostic testing with chromosomal microarray. It will provide long-term outcomes of fetal genomic variants to guide evidence-based pre-and postnatal care. This, in turn, will inform future efforts to mitigate the negative consequences of conveying genomic uncertainty during pregnancy.

TRIAL REGISTRATION

ACTRN12620000446965p ; Registered on April 6, 2020.

Technological readiness and implementation of genomic-driven precision medicine for complex diseases

The fields of human genetics and genomics have generated considerable knowledge about the mechanistic basis of many diseases. Genomic approaches to diagnosis, prognostication, prevention and treatment - genomic-driven precision medicine (GDPM) - may help optimize medical practice. Here, we provide a comprehensive review of GDPM of complex diseases across major medical specialties. We focus on technological readiness: how rapidly a test can be implemented into health care. Although these areas of medicine are diverse, key similarities exist across almost all areas. Many medical areas have, within their standards of care, at least one GDPM test for a genetic variant of strong effect that aids the identification/diagnosis of a more homogeneous subset within a larger disease group or identifies a subset with different therapeutic requirements. However, for almost all complex diseases, the majority of patients do not carry established single-gene mutations with large effects. Thus, research is underway that seeks to determine the polygenic basis of many complex diseases. Nevertheless, most complex diseases are caused by the interplay of genetic, behavioural and environmental risk factors, which will likely necessitate models for prediction and diagnosis that incorporate genetic and non-genetic data.

A minimum estimate of the prevalence of 22q11 deletion syndrome and other chromosome abnormalities in a combined prenatal and postnatal cohort

STUDY QUESTION

What is the frequency of major chromosome abnormalities in a population-based diagnostic data set of genomic tests performed on miscarriage, fetal and infant samples in a state with >73 000 annual births?

SUMMARY ANSWER

The overall frequency of major chromosome abnormalities in the entire cohort was 28.2% (2493/8826), with a significant decrease in the detection of major chromosome abnormalities with later developmental stage, from 50.9% to 21.3% to 15.6% of tests in the miscarriage, prenatal and postnatal cohorts, respectively.

WHAT IS KNOWN ALREADY

Over the past decade, technological advances have revolutionized genomic testing at every stage of reproduction. Chromosomal microarrays (CMAs) are now the gold standard of chromosome assessment in prenatal diagnosis and pediatrics.

STUDY DESIGN, SIZE, DURATION

A population-based cohort study including all chromosome analysis was performed in the Australian state of Victoria during a 24-month period from January 2015 to December 2016. All samples obtained via invasive prenatal diagnosis and postnatal samples from pregnancy tissue and infants ≤12 months of age were included.

PARTICIPANTS/MATERIALS, SETTING, METHODS

A research collaboration of screening and diagnostic units in the Australian state of Victoria was formed (the Perinatal Record Linkage collaboration), capturing all instances of prenatal and postnatal chromosome testing performed in the state. Victoria has over 73 000 births per annum and a median maternal age of 31.5 years. We analyzed our population-based diagnostic data set for (i) chromosome assessment of miscarriage, prenatal diagnosis and postnatal samples; (ii) testing indications and diagnostic yields for each of these cohorts; (iii) and the combined prenatal/infant prevalence of 22q11.2 deletion syndrome (DS) as a proportion of all births ≥20 weeks gestation.

MAIN RESULTS AND THE ROLE OF CHANCE

During the 24-month study period, a total of 8826 chromosomal analyses were performed on prenatal and postnatal specimens in Victoria. The vast majority (91.2%) of all chromosome analyses were performed with CMA.The overall frequency of major chromosome abnormalities in the entire cohort was 28.2% (2493/8826). There was a significant decreasing trend in the percentage of chromosome abnormalities with later developmental stage from 50.9% to 21.3% to 15.6% in the miscarriage, prenatal and postnatal cohorts, respectively (χ2 trend = 790.0, P < 0.0001). The total frequency of abnormalities in the live infant subgroup was 13.4% (244/1816). The frequencies of pathogenic copy number variants (CNVs) detected via CMA for the miscarriage, prenatal and postnatal cohorts were 1.9% (50/2573), 2.2% (82/3661) and 4.9% (127/2592), respectively. There was a significant increasing trend in the frequency of pathogenic CNVs with later developmental stage (χ2 trend = 39.72, P < 0.0001). For the subgroup of live infants, the pathogenic CNV frequency on CMA analysis was 6.0% (109/1816). There were 38 diagnoses of 22q11.2 DS, including 1 miscarriage, 15 prenatal and 22 postnatal cases. After excluding the miscarriage case and accounting for duplicate testing, the estimated prevalence of 22q11 DS was 1 in 4558 Victorian births.

LIMITATIONS, REASONS FOR CAUTION

Clinical information was missing on 11.6% of postnatal samples, and gestational age was rarely provided on the miscarriage specimens. We were unable to obtain rates of termination of pregnancy and stillbirth in our cohort due to incomplete data provided by clinical referrers. We therefore cannot make conclusions on pregnancy or infant outcome following diagnostic testing. Childhood and adult diagnoses of 22q11 DS were not collected.

WIDER IMPLICATIONS OF THE FINDINGS

Our study marks a complete transition in genomic testing from the G-banded karyotype era, with CMA now established as the first line investigation for pregnancy losses, fetal diagnosis and newborn/infant assessment in a high-income setting. Integration of prenatal and postnatal diagnostic data sets provides important opportunities for estimating the prevalence of clinically important congenital syndromes, such as 22q11 DS.

STUDY FUNDING/COMPETING INTEREST(S)

L.H. is funded by a National Health and Medical Research Council Early Career Fellowship (1105603); A.L. was funded by a Mercy Perinatal Research Fellowship; J.H. was funded by a National Health and Medical Research Council Senior Research Fellowship (10121252). The funding bodies had no role in the conduct of the research or the manuscript. Discretionary funding from the Murdoch Children's Research Institute has supported the prenatal diagnosis data collection and reporting over the years.Dr Ricardo Palma-Dias reports a commercial relationship with Roche Diagnostics, personal fees from Philips Ultrasound, outside the submitted work. Debbie Nisbet reports a commercial relationship with Roche Diagnostics, outside the submitted work.

TRIAL REGISTRATION NUMBER

NA.

Genetic Counseling and Assisted Reproductive Technologies

Despite the ever-increasing number of patients undergoing fertility treatments and the expanded use of genetic testing in this context, there has been limited focus in the literature on the involvement of genetics professionals in the assisted reproductive technology (ART) setting. Here we discuss the importance of genetic counseling within reproductive medicine. We review how genetic testing of embryos is performed, the process of gamete donation, the challenges associated with genetic testing, and the complexities of genetic test result interpretation.

Re-examining the Ethics of Genetic Counselling in the Genomic Era

Respect for patient autonomy has served as the dominant ethical principle of genetic counselling, but as we move into a genomic era, it is time to actively re-examine the role that this principle plays in genetic counselling practice. In this paper, we argue that the field of genetic counselling should move away from its emphasis on patient autonomy and toward the incorporation of a more balanced set of principles that allows counsellors to offer clear guidance about how best to obtain or use genetic information. We begin with a brief history of how respect for patient autonomy gained such emphasis in the field and how it has taken on various manifestations over time, including the problematic concept of nondirectiveness. After acknowledging the field's preliminary move away from nondirectiveness, we turn to a series of arguments about why the continued dominance of patient autonomy has become untenable given the arrival of the genomic era. To conclude, we describe how a more complete set of bioethical principles can be adapted and used by genetic counsellors to strengthen their practice without undermining patient autonomy.

Do patients who achieve pregnancy using IVF-PGS do the recommended genetic diagnostic testing in pregnancy?

PURPOSE

Patients undergoing in-vitro fertilization (IVF) with preimplantation genetic screening (PGS) are counseled about the limitations of this technique. As part of the consent process for PGS, physicians recommend diagnostic genetic testing performed in early pregnancy to definitively rule out chromosomal abnormalities. We have noted anecdotally, however, that few patients undergo the recommended diagnostic testing. In this study, we are examining if women who conceived using IVF-PGS did early pregnancy chromosomal testing, and if they did, what type of testing they had.

METHODS

This study was performed from 2015 to 2017 in the Division of Reproductive Endocrinology and Infertility at Northwestern University. We included patients who became pregnant after IVF-PGS who were seen by the Division of Reproductive Genetics and non-PGS control group.

RESULTS

Sixty-eight patients were included. A total of 50 patients (73.5%) opted for non-invasive prenatal screening; 5 (7.4%) had invasive testing (4 had chorionic villus sampling and 1 had amniocentesis). A total of 13 patients (19%) declined further genetic testing. When comparing demographic data, the mean age was significantly higher in the group of patients who pursued non-invasive testing than in the group who declined further testing (37.15 vs 34.05 years old, p < 0.05). Control group declined invasive diagnostic testing.

CONCLUSIONS

Most patients who conceive using IVF-PGS do not pursue diagnostic prenatal chromosomal testing. Future studies focusing on decision making in this patient group are warranted to further elucidate why a small percentage of patients opt for diagnostic testing, even when adequately counseled about the inherent limitations of PGS.

An update on current prenatal testing options: first trimester and noninvasive prenatal testing

Prenatal genetic testing is rapidly evolving and requires that prenatal care providers stay up-to-date with accurate, evidence-based knowledge. Noninvasive prenatal testing (NIPT), first trimester maternal serum markers, and fetal nuchal translucency are the most recently developed screening tests added to the testing repertoire for detection of chromosomal disorders such as trisomy 21 (Down syndrome). NIPT is a new, highly accurate technique that uses maternal serum and is rapidly being introduced as a first trimester screening tool and increasingly being requested by pregnant women. The American College of Obstetricians and Gynecologists recommends that all pregnant women be offered first and second trimester screening options, regardless of risk status, but does not yet recommend NIPT. It is important for prenatal care providers to be aware of and understand these testing options in order to assist women and their families in making well-informed decisions during pregnancy. The purpose of this article is to update midwives and other prenatal care providers on the current prenatal genetic testing options available and how to appropriately offer and discuss them with their clients. We discuss how these tests work; what to do with the results; and most importantly, how to support and communicate accurate information to women and families as they navigate through an increasingly complicated array of testing choices.

The impact of financing of screening tests on utilization and outcomes: The case of amniocentesis

We use a 1993 policy change in Israel's public healthcare system that lowered the eligibility age for amniocentesis to 35 to study the effects of financing of screening tests. Financing is found to have increased amniocentesis testing by about 35%. At ages above the eligibility threshold, utilization rates rose to roughly 33%, reflection nearly full takeup among prospective users of amniocentesis. Additionally, whereas below the age-35 threshold amniocentesis utilization rates increase with maternal age, this relation is muted above this age. Finally, no evidence is found that financing affects outcomes such as pregnancy terminations and births of children with Down syndrome. These results support the view that women above the eligibility threshold tend to refrain from acquiring inexpensive information about their degree of risk that absent the financing they would acquire, and instead, undergo the accurate and costly test regardless of additional information that noninvasive screening would provide.

Newborn screening and the era of medical genomics

Across the span of the last 75+ years, technological and conceptual advances in genetics have found rapid implementation at the beginning of human life. From karyotype testing, to molecular cytogenetics, to gene panel testing, and now to whole exome and whole genome sequencing, each iterative expansion of our capability to acquire genetic data on the next generation has been implemented quickly in the clinical setting. In tandem, our continuously expanding ability to acquire large volumes of genetic data has generated its own challenges in terms of interpretation, clinical utility of the information, and concerns over privacy and discrimination; for the first time, we are faced with the possibility of having complete access to our genetic data from birth, if not shortly after conception. Here, we discuss the evolution of the field toward this new reality and we consider the potentially far-reaching consequences and, at present, an unclear path toward developing best practices for implementation.

The gen-ethics bowl - an in-class activity combining genetics and bioethics

Undergraduate science professors are capable of teaching the scientific principles behind new genetic technologies. However, they are not often readied to explore the ethical and social implications. We created an ethics bowl that brings together students in genetic and healthcare ethics courses to analyze ethical issues in genetics. It is an engaging, challenging, and rewarding experience that provides students with the tools to identify ethical elements in science. This proves to be a wonderful first step in training morally sensitive scientists.

Prenatal diagnosis: the irresistible rise of the 'visible fetus'

Prenatal diagnosis was developed in the 1970s, a result of a partly contingent coming together of three medical innovations-amniocentesis, the study of human chromosomes and obstetrical ultrasound-with a social innovation, the decriminalization of abortion. Initially this diagnostic approach was proposed only to women at high risk of fetal malformations. Later, however, the supervision of the fetus was extended to all pregnant women. The latter step was strongly favoured by professionals' aspiration to prevent the birth of children with Down syndrome, an inborn condition perceived as a source of suffering for families and a burden on public purse. Experts who promoted screening for 'Down risk' assumed that the majority of women who carry a Down fetus will decide to terminate the pregnancy, and will provide a private solution to a public health problem. The generalization of screening for Down risk increased in turn the frequency of diagnoses of other, confirmed or potential fetal pathologies, and of dilemmas linked with such diagnoses. Debates on such dilemmas are usually limited to professionals. The transformation of prenatal diagnosis into a routine medical technology was, to a great extent, an invisible revolution.

Trophoblast retrieval and isolation from the cervix (TRIC) for noninvasive prenatal screening at 5 to 20 weeks of gestation

OBJECTIVE

To use trophoblast cells accumulating in the endocervical canal at the beginning of pregnancy for noninvasive prenatal testing.

DESIGN

Prospective, double-blinded test for fetal gender.

SETTING

Academic medical center.

PATIENT(S)

Fifty-six women with singleton pregnancies at gestational age 5-20 weeks.

INTERVENTION(S)

Isolation of fetal cells from resident maternal cells in endocervical specimens using anti-human leukocyte antigen G coupled to magnetic nanoparticles; cell phenotyping immunofluorescently with a panel of trophoblast subtype-specific proteins; DNA integrity assessment with terminal dUTP nick-end labeling (TUNEL); and polymerase chain reaction (PCR) and fluorescent in situ hybridization (FISH) to detect sex chromosomes in individual cells.

MAIN OUTCOME MEASURE(S)

Trophoblast phenotype, TUNEL index, and percentage male cells.

RESULT(S)

The women were given a routine Papanicolaou test; fetal genders were verified from medical records. Recovery after immunomagnetic isolation averaged 746±59 cells across gestational age, with 99% expressing chorionic gonadotropin, whereas the depleted cell fraction expressed none. The isolated cells had an extravillous trophoblast phenotype and intact nuclear DNA (>95%). Fetal gender was determined in 20 specimens without error by PCR. The FISH analysis of isolated cells from male specimens validated their fetal origin.

CONCLUSION(S)

Noninvasive prenatal testing is feasible beginning at a gestational age of 5 weeks.

Prenatal chromosomal microarray for the Catholic physician

Prenatal chromosomal microarray (CMA) is a test that is used to diagnose certain genetic problems in the fetus. While the test has been used in the pediatric setting for several years, it is now being introduced for use in the prenatal setting. The test offers great hope for detection of certain genetic defects in the fetus so that early intervention can be performed to improve the outcome for that individual. As with many biotechnical advances, CMA comes with certain bioethical issues that need to be addressed prior to its implementation. This paper is intended to provide guidance to all those that provide counseling regarding genetic testing options during pregnancy.

Current management of sickle cell disease in pregnancy

Life expectancy in sickle cell disease (SCD) has increased substantially and thus women with SCD are almost universally reaching child-bearing age. Studies on potential complications during pregnancy have generated mixed data; however, it is generally accepted that women with SCD are at higher risk for adverse pregnancy outcomes and maternal mortality. It is therefore critical that their care be provided by a team that includes a hematologist and a maternal-fetal medicine specialist. Despite the published risks, women with SCD are capable of successful pregnancy outcomes with proper education and well-coordinated multidisciplinary care. Further investigation is needed to standardize management.

Opportunity for selection in human health

Natural selection defined by differential survival and reproduction of individuals in populations is influenced by genetic, developmental, and environmental factors operating at every age and stage in human life history: generation of gametes, conception, birth, maturation, reproduction, senescence, and death. Biological systems are built upon a hierarchical organization nesting subcellular organelles, cells, tissues, and organs within individuals, individuals within families, and families within populations, and the latter among other populations. Natural selection often acts simultaneously at more than one level of biological organization and on specific traits, which we define as multilevel selection. Under this model, the individual is a fundamental unit of biological organization and also of selection, imbedded in a larger evolutionary context, just as it is a unit of medical intervention imbedded in larger biological, cultural, and environmental contexts. Here, we view human health and life span as necessary consequences of natural selection, operating at all levels and phases of biological hierarchy in human life history as well as in sociological and environmental milieu. An understanding of the spectrum of opportunities for natural selection will help us develop novel approaches to improving healthy life span through specific and global interventions that simultaneously focus on multiple levels of biological organization. Indeed, many opportunities exist to apply multilevel selection models employed in evolutionary biology and biodemography to improving human health at all hierarchical levels. Multilevel selection perspective provides a rational theoretical foundation for a synthesis of medicine and evolution that could lead to discovering effective predictive, preventive, palliative, potentially curative, and individualized approaches in medicine and in global health programs.

Genomics, personalized medicine, and pediatrics

Genomic discoveries are advancing biomedicine at an ever-increasing pace. Pediatrics is near the epicenter of these discoveries, which are revising our understanding of the genome and its function. Since the completion of the Human Genome Project in 2003, dramatic reductions in the cost of genotyping, and more recently sequencing, have permitted the study of the genomes of a great number of species as well as humans. These studies have led to insights on gene regulation and the complex interplay of factors responsible for normal development and biology. Study of single-gene disorders has greatly benefited from the genomics revolution and tests are now available for well over 2000 Mendelian conditions; availability of these tests are changing screening and diagnosis paradigms for rare conditions. Genomics is also yielding an increased understanding of common conditions such as diabetes, obesity, asthma, cancers, and mental health conditions. Personalized medicine, an approach to care in which an individual's genomic information is used to help tailor interventions to maximize health outcomes, is rapidly becoming a reality for a variety of conditions. Though challenges remain in translating new genomic insights into improved patient health, today's pediatricians and their patients will increasingly benefit from this watershed moment in the biological sciences.

The evolving role of genetics in reproductive medicine

As medicine has evolved over the last century, medical genetics has grown from nonexistence to one of the most visible aspects of how we understand and treat disease. This increased role of genetics within medicine will only increase in the coming years, and its role in reproductive medicine will be significant. Genetics has emerged as a primary focus of research with translational applications within reproductive medicine. The aim of this article is to outline the applications of genetics currently available, and how these technologies can provide a positive impact on patient care.

The root of reduced fertility in aged women and possible therapentic options: current status and future perspects

It is well known that maternal ageing not only causes increased spontaneous abortion and reduced fertility, but it is also a high genetic disease risk. Although assisted reproductive technologies (ARTs) have been widely used to treat infertility, the overall success is still low. The main reasons for age-related changes include reduced follicle number, compromised oocyte quality especially aneuploidy, altered reproductive endocrinology, and increased reproductive tract defect. Various approaches for improving or treating infertility in aged women including controlled ovarian hyperstimulation with intrauterine insemination (IUI), IVF/ICSI-ET, ovarian reserve testing, preimplantation genetic diagnosis and screening (PGD/PGS), oocyte selection and donation, oocyte and ovary tissue cryopreservation before ageing, miscarriage prevention, and caloric restriction are summarized in this review. Future potential reproductive techniques for infertile older women including oocyte and zygote micromanipulations, derivation of oocytes from germ stem cells, ES cells, and iPS cells, as well as through bone marrow transplantation are discussed.

Chromosomal microarray versus karyotyping for prenatal diagnosis

BACKGROUND

Chromosomal microarray analysis has emerged as a primary diagnostic tool for the evaluation of developmental delay and structural malformations in children. We aimed to evaluate the accuracy, efficacy, and incremental yield of chromosomal microarray analysis as compared with karyotyping for routine prenatal diagnosis.

METHODS

Samples from women undergoing prenatal diagnosis at 29 centers were sent to a central karyotyping laboratory. Each sample was split in two; standard karyotyping was performed on one portion and the other was sent to one of four laboratories for chromosomal microarray.

RESULTS

We enrolled a total of 4406 women. Indications for prenatal diagnosis were advanced maternal age (46.6%), abnormal result on Down's syndrome screening (18.8%), structural anomalies on ultrasonography (25.2%), and other indications (9.4%). In 4340 (98.8%) of the fetal samples, microarray analysis was successful; 87.9% of samples could be used without tissue culture. Microarray analysis of the 4282 nonmosaic samples identified all the aneuploidies and unbalanced rearrangements identified on karyotyping but did not identify balanced translocations and fetal triploidy. In samples with a normal karyotype, microarray analysis revealed clinically relevant deletions or duplications in 6.0% with a structural anomaly and in 1.7% of those whose indications were advanced maternal age or positive screening results.

CONCLUSIONS

In the context of prenatal diagnostic testing, chromosomal microarray analysis identified additional, clinically significant cytogenetic information as compared with karyotyping and was equally efficacious in identifying aneuploidies and unbalanced rearrangements but did not identify balanced translocations and triploidies. (Funded by the Eunice Kennedy Shriver National Institute of Child Health and Human Development and others; ClinicalTrials.gov number, NCT01279733.).

Non-invasive prenatal measurement of the fetal genome

The vast majority of prenatal genetic testing requires invasive sampling. Since this poses a risk to the fetus, one must make a decision that weighs the desire for genetic information against the risk of an adverse outcome due to hazards of the testing process. These issues are not required to be coupled, and it would be desirable to discover genetic information about the fetus without incurring a health risk. Here we demonstrate that it is possible to noninvasively sequence the entire prenatal genome. Our results show that molecular counting of parental haplotypes in maternal plasma by shotgun sequencing of maternal plasma DNA allows the inherited fetal genome to be deciphered noninvasively. We also applied the counting principle directly to each allele in the fetal exome by performing exome capture on maternal plasma DNA prior to shotgun sequencing. This approach enables noninvasive exome screening of clinically relevant and deleterious alleles that were paternally inherited or had arisen as de novo germline mutations, and complements the haplotype counting approach to provide a comprehensive view of the fetal genome. Noninvasive determination of the fetal genome may ultimately facilitate the diagnosis of all inherited and de novo genetic disease.

Fetal Laboratory Medicine: On the Frontier of Maternal–Fetal Medicine

BACKGROUND

Emerging antenatal interventions and care delivery to the fetus require diagnostic support, including laboratory technologies, appropriate methodologies, establishment of special algorithms, and interpretative guidelines for clinical decision-making.

CONTENT

Fetal diagnostic and therapeutic interventions vary in invasiveness and are associated with a spectrum of risks and benefits. Fetal laboratory assessments are well served by miniaturized diagnostic methods for blood analysis. Expedited turnaround times are mandatory to support invasive interventions such as cordocentesis and intrauterine transfusions. Health-associated reference intervals are required for fetal test interpretation. Fetal blood sampling by cordocentesis carries substantial risk and is therefore performed only when fetal health is impaired, or at risk. When the suspected pathology is not confirmed, however, normative fetal data can be collected. Strategies for assurance of sample integrity from cordocenteses and confirmation of fetal origin are described. After birth, definitive assessment of prenatal environmental and/or drug exposures to the fetus can be retrospectively assessed by analysis of meconium, hair, and other alternative matrices. A rapidly advancing technology for fetal assessment is the use of fetal laboratory diagnostic techniques that use cell-free fetal DNA collected from maternal plasma, and genetic analysis based on molecular counting techniques.

SUMMARY

Developmental changes in fetal biochemical and hematologic parameters in health and disease are continually delineated by analysis of our collective outcome-based experience. Noninvasive technologies for fetal evaluation are realizing the promise of lower risk yet robust diagnostics; examples include sampling and analysis of free fetal DNA from maternal blood, and analysis of fetal products accessible at maternal sites. Application of diagnostic technologies for nonmedical purposes (e.g., sex selection) underscores the importance of ethical guidelines for new technology implementation.